Commodore 64 Futureproofing
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- Опубликовано: 2 май 2017
- I'm presenting some methods to prolong the life of a Commodore 64 in this video. Includes recapping, heatsinking and even a crude overvoltage protection using a suppressor diode.
Near the end of the video I mention some further preventive maintenance measures. Replacing the bridge rectifier and the voltage regulators might also be a good idea.
I got the idea for the suppressor diode from this (German) document that also has a variety of other interesting C64 hardware stuff in it: ftp.fau.de/aminet/docs/hard/R...
Fellow RUclipsr bwack has developed a very sophisticated overvoltage (and other power supply faults) protection, the C64saver. Highly recommended (you can also buy these from him if you contact him): • C64 Saver (over-voltag...
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Thanks! 
Наука
I cannot claim to be a thermal efficiency guru but i would like to make few suggestion one might find useful at getting best thermal efficiency as possible from the chip-sets used
Jan is obviously using the components he had available at the time and in such low heat generating chips the results are sufficient
Still there are few options one could consider.
1.Thermal paste and and compounds are superior to thermal tape.
2.One should always use a single large as possible heatsinsk to increase the thermal efficiency also one should consider the thermal stress of unevenly cooled components.
Although somewhat academic point at these temperatures it is not something one should ignore.
Jan pointed out the inherent problems of attaching non framed clip-less heat-sinks to the IC's.
There are few options available.
1.One can use thermal glue (what i do not recommend as it has inferior thermal conductivity and it will be difficult to remove the heat-sink if it becomes necessary.
2.It is possible to use "tag the corner" method using tiny drop of thermal clue in the corner of heat-sink to attach it to the component. (for a hax if thermal clue is not available one can tag the corner with super clue to keep it attached after paste has been applied)
One can tag two or more corners depending of the mechanical stress expected to the board to secure the heat-sink.
Jan did not wish to have a fan in the computer for nostalgia reasons and keeping the purity of design.
It is good to point out a fan can increase heat-sink efficiency greatly
Passive cooling methods without airflow are very inefficient and one in my opinion should consider adding a small internal fan.
Thanks for sharing! All valid and good points of course. I'm pinning this comment.
Don't forget about convection (heat rises and rises much better the more contact surface that is available from the heatsink). BTW thermal epoxy (not glue) is not inferior, if used properly, it is every bit as good as standard thermal paste. Thermal tape is much better than you are giving it credit for. Look at datasheets that show thermal conductivity of tape, epoxy and paste. The difference is not quite as poor as a person might think, especially for such low power devices.
Jan did something very solid for thermal management. The case is not without airflow (it's just not driven by a fan) and the heatsinks will help a ton.
Indeed, i used silver paste (normally used on modern processors) when i fitted heatsinks.
Thanks for a great video with lots of good tips. I have just started to restore my old c64 bread-bin - hope I can get everything to work :)
Oh, glad it is useful to you! Hope you can restore your bread bin to its former glory. Such a rewarding experience! :)
Nice and very interesting video: thanks Jan! ...and Happy New Year! :D
Thank you Joe and happy New Year to you, too! :)
Very useful and educational. Thank you, Jan.
Awesome work! I really enjoy your videos.
+Greisis Workbench Thanks a lot! I also enjoy your videos very much. :)
Many good tips there! The pdf you linked to is packed with tips. Seems like the author worked on it for many years.
+bwack Thanks! :) I think the PDF was compiled by a group of informatics students and professors a while ago. So happy that I came across this document.
Great information. A soldering point; when you were using soldering wick for diode holes, the wick was old full of solder and too long and no apparent liquid resin. Here is my method which well. Always use clean END of wick spreading considerable resin along wick say 1/2 in.. When you begin to make sure good contact on braid; when it heats up you will find that resin will heat first, when the solder melts it will move up and away from the hole on the fluxed wick. Fascinating to watch. If this does not read well no edit.
It always warms my heart to see a classic computer restored. I'm more of a ZX Spectrum guy but one thing that helped improve thermal efficiency and overall stability was switching to a modern regulated power supply in combination with using Traco 2-2450 voltage regulator instead of the old 7805. But honestly, I'm not even familiar with C64 schematics. Regarding heat sinks, it certainly won't do any harm but without air circulation I'm not sure if it's actually that effective. But considering that replacements are increasingly harder to come by, it probably makes sense.
Awesome job! I really enjoyed this video . Subbed.
Thanks & welcome aboard. :)
I removed the fan from my desoldering station as it was so bloody loud. So far it has givin me no issues without it.
lol, I left my previous comment before I watched the whole video. :D Glad to see you got the caps inside the RF modulator too! I'm in the middle of my own c64 recapping project and I almost forgot about those caps myself.
Haha, yeah, I nearly forgot them, too. Replacing those indeed improved the quality of the video output drastically. :)
I see you use the A/V output jack - do you use composite or component (Y/C) connectors on the other end? I didn't know the RF modulator also generated those outputs.
The CRT shown here only has composite and RGB inputs so I'm using composite there. On my flatscreen I have an S-video adapter. Both have an improved picture after recapping.
Just finished recapping and heatsinking mine as well. Sitting on the coffee table cover open allowing the thermal epoxy to set. Didn't know which chip was the PLA - your video showed me which! same revision board too :)
+dash8brj Nice! Glad I could help. :) I'd also recommend leaving the cardboard shielding out of the C64 while you're at it. Didn't do it in the video but it really just blocks the airflow and has no real use otherwise (except for making the computer RF compliant).
Yep - I ripped that rubbish out when I first got the computer while I was fitting my jiffydos chip :)
+dash8brj Ah, nice. I'm going to get JiffyDOS soon, too. :)
Thanks for this video. I'll definitely give it a good look before trying to turn on my C64 that's been in my closet for years.
Hope it still works. :) Mostly, the power supplies fail over time and take out the ICs in the computer by producing overvoltage on the 5V line. Always a good idea to thoroughly test the PSU before connecting it in my experience. The things are very poorly constructed.
Polymeter before connecting then. Thanks. :)
some tech notes. *1* . The c64 power supply "brick" provided 9 volts AC to the C64 motherboard. It goes through a bridge rectifier and is regulated with a 7805 down to Vcc 5vdc to power all the digital ICs. The 12 vdc was a tricky capacitor/diode network that increased the 9 vac to between 18 to 24 volts, and then regulated with a 7812 back down to 12Vdc. The 12 volt regulator rarely had problems since the only two chips to use it was the SID and VIC, but the 7805 always ran very hot. This board was an upgrade that mounted the 7805 to a heat sink (24:10) but earlier board versions had a small, inadequate vertical finned sink. A down and dirty solution to this was to get a second 7805 and solder it in parallel, directly on to the existing IC (note: both ICs MUST be oriented exactly the same). This doubles the current sinking capacity of the 5 volt regulator and split the heat dissipation between the two regulators. This heat sink probably solved the heating problem on later boards. There is also a 5 vdc provided by the original power supply that was specifically used to power the various oscillators on the board - system clock, VIC and CIA timers, and a 556 timer that generated the hardwired, CPU reset pulse. This was pin 5 of the power plug.
*2* . Throw away the "brick" and build your own power supply. It should provide 5vdc at above 4 amps or 20 watts and 9vac at about 1 amp (10 watts) or better. Connect the 9vac to pins 7 and 6 of the power connector orientation does not matter since it is AC. For the 5 vdc, desolder the 7805 and conneect the +5vdc to the hole labled #3 (the center hole). the 5v ground can be soldered to any ground plane area of the board, or the #2 hole where the 7805 was mounted is actually circuit ground.
*3* . The 16 pin IC just below the CIA2 is an octal inverter LS7406N. These "not" gates are used to buffer CIA2's output to the RS-232 edge connector on the top left of the board (the "User Port"). It protected the CAI but did not have the power to drive actual data lines to external RS-232 devices (like a printer) and would cook itself after a few collective hours of use. Replace this IC with SN54LS06 (pin for pin replacement) which can sink about 3 times the current (40m amps) as the 7406N ... or better yet, build an RS-232 connector with a "line driver" buffer built in using MOS drivers.
*4* . VIC chip only had heat problems if you used a T.V. as monitor. If you use the direct video monitor the VIC runs cool as a cucumber.
Still runs way cooler than an original PS3
Haha, you're probably right. :D
Remember when you bought a game at the shop, got home, put it in the computer and ... started playing? No multi-GB first-day patches to install first ... ;)
Hello sir. Any idea where to fit the saver diode on the 250407 Rev B board? There are no spare holes at that location, though FB18 is nearby and populated with a diode already. Thanks!
Here's a picture (taken from the pdf linked in the desription): www.janbeta.net/files/DiodeASS250407.jpg
Jan Beta Thank you! I think I need to learn German 😉
Thanks. Did you know these were originally invented to protect against lightning strikes damaging boards? Ergo the C64 power supply is lightning in a box.
Haha, sounds about right. At least they are dangerous, too. ;)
Thanks for being the inspiration for this video: ruclips.net/video/6Tzib7u1wqg/видео.html
Nice video Jan;)..love the game too;)
Thanks! Yeah, it's a very lovely game. I don't regret buying it even if I suck at it. ;)
oh my god I hate those large mass fields to solder on them and it looked so flawless here
Tip I use for soldering components that need a lot of heat is add a heat shunt on the component side I generally use a pair of self closing tweezers, good for LEDs too.
+Brian Jones Did that before on LEDs with one of those larger crocodile clips but didn't think of it this time.
Very good video!
Thank you Sir! :)
hi Jan
I have just got me a c64c having stumbled onto yours, and others, videos and its got my nostalgia juices flowing :)
my question is could the suppressor diode be put inside the supply itself on the 5v line as I'm planning building an internal bwak saver anyway
Yes, you could put it into the PSU if that is fused. Bear in mind that it's a very crude way of overvoltage protection. There's definitely better solutions for that (like Ray Carlsen's or bwack's C64 saver).
Using a zener like that is a nice way to protect against over voltage - but I would recommend checking out bwack's 5v saver, rather than risk almost 7v on your system. His little adapter there will cut the power at anything over ~5.4v.
Yes, I know the C64saver, I actually linked to bwack in the video. ;) This diode protection is only good for certain scenarios and meant as a sort of last line of defense. Just found it an interesting and easy way to somewhat protect the ICs.
Hello! Nice and interesting work on this old beauty :) Can u please write down the name of the diode? Thanks in advance!
+Luka Niko Thanks! Sure. It's a P6KE-6.8A transient voltage suppressor diode. pdf1.alldatasheet.com/datasheet-pdf/view/210086/FCI/P6KE-6.8A.html
Jan Beta Really kind! I have found the zener on the RS shop. Thank you for your answer!
Hello Jan! Really kind of you! Thank you so much, i have found the diode on the RS store.
Well done
Hi Jan Beta, thnx a lot for this informative and well-prepared video.
I have a question about the diode type.
can I use 6.2V 1/2W Zener diodes or should it be an avalanche diode type?
You absolutely need a suppressor/avalanche diode. It works slightly different than zener diodes. I recommend using the P6K8 6.8A type I used myself. Widely available, dirt cheap and made for the purpose.
Jan Beta thnx a lot. Just bought some of those. 👍👍
I didnt do the modulator caps but I did heatsink everything except the CIAs as they didnt really get warm. I replaced the regulator ICs on board which you didnt seem to do. At this age its good to refresh them.
Yes, replacing the regulators is a very good idea. I added it in the description later and actually did replace them on my daily driver machine.
What diode did you use on the volt mod? A P6KE33A 28.2V 600W DO-15 or a P6KE43A 36.8V 600W DO-15? I dont think you said any exact number.
Hi. Not directly related to this topic, but do you also have some experience with the C64 monitors? The 1701 or 1702 model. Is there any need to replace the caps in these monitors to make them future proof?
In my experience, capacitors in these old monitors die very frequently because they are constantly stressed by heat. It makes perfect sense to replace them with good ones (preferably with a high temperature rating). Be very careful when working on CRTs though and properly discharge them before.
Very nice! 30 min. is nothing, when it's very interesting. :) I have interest in electronics, and moderate soldering skills, but lacking broad knowledge on components. I did the Composite mod on my G7000. That's probably one of the easier ones, but it still counts for me.. :) I have been worrying about my A500 (silently in the back of my mind). It works and shows no signs of anything being wrong, but it's so old and I'd hate to have it die on me. I got my A1200 recapped (not by me), but not the A500. I've been thinking of doing it myself, but the thought scares me a bit. But maybe it's not hard? Hm.. Oh, sorry for the long comment.. :) Great video!
Thanks for the long comment. ;) I recommend trying to recap the A500. If you have a reasonably decent soldering iron (you need quite some heat on those damn ground planes) it's not too hard, I'd say. Not too many caps on the A500 boards, too.
I have a soldering station that goes to around 480 celsius. Guess that's enough? Seem to remember you went to 450 at some point. What's the recommended temperature for fine electronics? 350-400? What I fear the most, is those damn small round caps with no legs. I may seek out a few guides/videos and then go for it, if I deem it doable by me.. :)
That should be enough. It depends a lot on the type of tip (I use 1-1.2mm chisel tips mostly) and your personal habits at which temperature you should solder. I'm using quite a high temperature of around 350-370C usually (and take care to not touch sensitive parts for too long). Electrolytic capacitors can take quite a lot of heat so not much danger there, I guess.
The A500 caps all have legs. Some of them are cut quite short but all are nice through-hole components. Or what do you mean by the small ones without legs?
The thing to worry about is getting the right capacitor in the right spot (I tend to do one value at a time to not get confused) and the polarity (which is marked correctly on all A500 boards AFAIK). Technically, it's not very difficult if you have ever soldered on a PCB.
Excuse my layman explanation, but I don't know what they are called. :) I guess they do have legs (oh.. "pins"..?) What I meant by "no legs", was it's not those through-hole ones. It's the small low silver ones, which are mounted on the surface. Oh, "surface mounted" is the correct term, right? :) What are they called? Electrolytic? SMD? But if the A500's don't have those at all, I have little to worry about. I just ordered some desoldering wick on eBay. Guess I don't need it after all it seems. But can't hurt to have it lying around.
I am aware I shouldn't apply heat for too long at a time. I think I'm gonna order a capacitor pack for this job. I see amigastore.eu has them.
Thanks a lot for your input, Jan. ;)
Ah, they are called all of the above: Electrolytic SMD (which means "surface mount device") capacitors. None of those in the A500, so nothing to worry about. Commodore only used those in the newer models. Solder wick is always handy to suck out remaining solder in case a component won't come loose easily. :)
The capacitor pack seems okay (a tad on the expensive side, but they say to be using good brand caps at least).
Happy to answer any (future) questions (if I can). ;)
I always loved how easy the C64 was to work on, for those who have the tools and know-how of soldering. Can't do that with a PC board!
On the back side of the board, is that the solder mask that's rippled? Or is the entire ground plane detaching and rippling in certain places?
With those voltage protection diodes, would it work to connect those in series with something like a piezo buzzer so there's an indication of a failing power supply that can be heard or seen?
And I totally love the artwork on that Bear Essentials package! That is really beautiful.
Yes, the old machines are really convenient to work on compared to modern stuff. There's still a lot of similarities from an electronics point of view but the parts got a lot smaller and faster. ;)
The rippled solder mask is quite common for boards from that era. They used more solder as an easy (and cheap) way to make the traces bigger (to take more current). When the added solder cooled it looked rippled.
The piezo buzzer is an interesting idea but it would probably not work as the diodes act VERY fast (that's why they are so good for this job) and the fuse would (hopefully) blow before the buzzer would make a sound.
The Bear Essentials is a great game, too. Highly recommended. They even released a tape version of it recently for added nostalgia. :)
Very cool video, Jan! I just got a package of heatsinks to try to cool down my 64s as well, but I'm not sure I got the right size - what dimensions are yours?
Also, very unusual trick with the suppressor diode - time to re-learn German and read that PDF!
+Boris Matešin I think mine are 1cm wide and 1,6 cm long. Not quite sure though. The correct size is not all that important, it should be no problem to let them overlap a bit as long as they don't touch any exposed traces/components. :)
Wow, 80's micros really were designed to cut as many design corners as they thought they could get away with didn't they? I was born a little too late to really say I grew up with these things but the family was always pretty poor so for a long time my idea of a 'computer' was a Sinclair Spectrum +3. I do love to see a little of how these machines work and watch them get repairs/maintenance to carry the poor things into the future... yes, even filthy Commodores! XD
Also, is it just my imagination that made the picture on that monitor sharper, brighter and more clear after you freshened up the modulator? It wouldn't surprise me if really old computers can have their output slowly degrade as their discreet components start to wear down rather than just outright failing one day.
Thanks! I love trying to preserve these machines and learn about them.
The picture quality improved quite a bit actually. Changing the caps on the board improved it a bit and recapping the modulator made it even better. Pretty clear picture now with less blur than before and clearer colors. :)
but what does a real/actual measurment provide. i.e. the normal white heat dispencer and the commodore metallic cover. i know some have paper with metallic like coating on it as well.
I have one other question. Did you replace every electrolytic cap on the board? Or did you only do the larger ones?
Yes, I replaced all electrolytic caps. In my experience, it's very often the smaller caps that start failing first. The larger filter caps (if they are good brand ones) tend to last a lot longer.
Thanks for the information! I'd have thought it would be the other way around with the smaller ones lasting longer. I'll definitely replace all the caps on the board, not just the big ones.
I'm wondering if there would be the need to recalibrate at least variable capacitors after recapping to get the best out of filtering and oscillating sub-circuits. They were calibrated with the capacitors in place and as capacitors differ slightly from the described capacity, retuning would be necessary?
In theory, yes. The values will be ever so slightly off. Although I think they are probably closer to the values they were originally calibrated at with new caps. I've usually seen improvements in picture quality after recapping so I guess the calibration is at least not way off.
Maybe elkos don't influence these trimmed filtering and oscillating sub-circuits because they are not a direct part of these circuits due to their polarized nature. Would be interesting to have service manuals about the trimming procedures, maybe one could fine-tune these circuits because of other capacitor types losing capacity over time too and expecting, that Commodore didn't aim a perfect 100% tuning because of economic efficiency.
How reliable are the processor, RAM, and other ICs? I work with old music equipment and I can say for sure that I have replaced way more ICs than capacitors in 1970s organs, keyboards, and drum machines.
They are not very reliable indeed. Especially some of the MOS logic ICs fail pretty frequently (they are only used on some boards though, Commodore mostly used other brand logic ICs later). The processor is pretty reliable and doesn't run very warm at all. The PLA, VIC II and RAM fail frequently, too. Hence the heat sinks to maybe make them live a bit longer.
I disagree: My C64 purchased in 1985 lasted for 20 years and it was the disk drive that died from a mechanical failure, not the computer. The epoxy encased power supplies that shipped with the C64 (mid 80's) would regularly fail, smoke and even catch on fire, so I didn't take the chance. Being an electronic tech, I built my own beefed up power supply when I began to feel the power "brick" getting hotter than usual. As my other comment says, I cooked the RS-232 output buffer running an HP 24 pin printer. At the time there was no IC to replace the 7406 with a higher current one so I had to replace it every so often until I built an inline RS-232 driver.
I didn't connect a lot of external devices to it and had the Commodore monitor which kept the VIC chip cool. I never lost any RAM and never had to replace any other chips. It only ended up as an attic relic because I could not find a replacement disk drive in 1996.
As a dedicated music device I think it would work well for you, especially if you can find the tech notes and/or kit to add a second SID chip. The drawback to the original SID was that it was not stereo output, but if you connected the audio RCA jack into a decent external amp the sound would blow you away. As a MIDI controller, I think there are better, more modern and faster options for this.
"Being an electronic tech, I build my own....." .That doesn't sound very assuring if you have to be a tech to keep things running reliably. But I do have instruments myself that can only be kept running because I have done serious workarounds and modifications to them. So I know the feeling.
The original C64 power supplies were crap. They produced a lot of heat and were encapsulated in epoxy resin that held the heat. Today you can buy upgraded, air cooled power supplies with higher output amperage and better heat sinking. Most of the power supply problems happened on systems that ran a lot of cartridge software because the power supply provided their power, also, which put extra strain on the supply. You can now interface a C64 to a PC and use the PC's hard drive for program storage although the disk drive was trouble free for the most part. The other problem I had with my C64 was because of my own customization and being too lazy to build a protection circuit... at first. Any commercial device, like a keyboard, that would hook into the RS-232 port would have a built in data line driver and take the load off the CIA output buffer. All in all, the C64 was and still is one of the most reliable electronic devices out there. In 10 years I have purchased 3 PCs due to burned out mother boards and fried CPUs. Most C64 end up in the attic or trash simply because they became outdated.
It's the same with home organs and a surprising amount of (music) keyboards. And actually power supplies are a problem in many products. I thinks it's because it's a section where you can cut a lot of corners and still have it working but with a much shorter lifetime. My Technics organ wastes about half of it's 110 Watt power consumption in the heat sinks. They are easy to repair however.
Hey Jan - you've probably mentioned this somewhere, but what type of desoldering iron do you use? I've tried various methods - braid, suction pump, cheapo Chinese irons, but I'm not very happy with any (okay, maybe skill level needs improving too). I did try to follow your affiliate link but Amazon kept sending me to the AU store and the link is lost.
It's a ZD-915. They are sold under a variety of brand names and some case designs differ a bit but afaik all basically the same design.
@@JanBeta Thanking you - will check it out. Want to socket some VIC-20 chips and some BBC Model B RAM but am tired of the tracks overheating and lifting, etc.
@@JanBeta Wow - what a revelation. I'm rapidly going through those filter pads as I de-solder and re-socket chips, etc. on old computers - I've been soldering ... or sodering as the American's say ;) ... since high school in the 80's but have never managed to acquire any real de-soldering skills - faulty RAM ... de-soldered and socketed new RAM ... faulty ROM socket ... de-soldered and new machined sockets ... faulty VIC chip ... de-soldered, socketed, new VIC ...
Great video! Where can I buy these heatsinks? That desoldering gun you have looks very handy but I think it's very expensive!
Thanks! I got the heatsinks from eBay. I think it's an international seller: www.ebay.de/itm/8-Stück-VGA-RAM-Kühler-I-Cooler-Selbstklebend-Aluminium-Heatsink/121997702605
The desoldering station varies in price every other month or so. I got it for around 80€ some time ago which is a good price for what it can do.
Is there any point in replacing the voltage regulators? I replaced mine as they cost like 50 cents a piece but I don't know if they really age in a similar way. They get really hot though, the heatsink for the 5V regulator is burning hot after a few minutes, the 12V regulator was also hot until I realized to push it down against the board properly, the old one was standing up for some reason
Really therapeutic couple of hours though, took a while with a regular iron and terrible desoldering pump but now I feel a lot better about using my C64 combined with the modern power supply. Also heatsinked it the day I got the machine like a year ago but I didn't think of recapping it until now
Nice video Jan!. I modified a power supply replacing the 7805 with a DC to DC converter, so runs cooler and is not so unreliable, at least that's what I think, what do you think?
+dergrunepunkt Definitely a good way to improve the power supply, I'd say. Check out GreisisWorkbench here on YT. He build a very nice slightly modernized C64 PSU and also used DC to DC converters.
I never replace capacitors on a C64 unless they are bad, which is really rare. I did some measurements, and all capacitors tested still had their original capacity after 3 decades. The C64 proves that the quality of electronic components was better in the past as it survives entire generations of computers that died from bad capacitors. To future proof a C64, my attention is more on the power supply: The LM7805 in the power supply is responsible for killing the C64 with over voltage, is the reason why there is not enough capacity to feed power hungry cartridges and it is nowadays considered immoral to have a power supply with ~60% efficiency. Further, the diodes in the power supply are underrated, Commodore did use 1A diodes, which the PSU is rated at 1.5A, often there are burn traces near the diodes due to heat. Replacing the rectifier board in the power supply with a board with a switching regulator on it, solves therefore quite a bit of problems.
You're right, I've also not yet encountered caps in a C64 that were completely bad. The ESR was a bit high for some but they all were functioning perfectly fine. Still, I think it's a good idea to generally replace caps after some decades as they fail for sure at some point and if you use good brand caps (I tend to use Panasonic wherever possible) you can be sure to be safe for another couple of decades. That said, I saw vintage amplifiers from the early seventies with caps still being perfectly fine so there's probably some truth to components being better back in the day.
And I totally agree on the power supply. These things are a real pain and I highly recommend getting something more modern as a replacement (I'm going to build my own PSU and try some other designs some time for sure). The suppressor diode protection I suggested in the video is only meant as a last line of defense. It's better to replace the PSU in the first place of course.
All electrolytic capacitors will fail eventually. And those caps in C64 are more than 30 years old. I've seen almost 50 year old caps that are in good shape (ESR) but I wouldn't trust them.
Electrolytics often measure the same amount of Farads in them even after a long time. This does not mean they are OK by a long shot! They leak corrosive electrolyte all over the board which will destroy a lot of stuff. After that there are things like ESR which will cause them to heat up and fail dramatically etc. Definitely replace them with high-quality ones for all gear like this, or at least test them with a proper meter for ESR an other characteristics.
i have a 250407 rev.B board giving me the "Searching for *" error and i know it's not the floppy drive and am trying to trace the fault, but i'm not good with a multimeter. it's my understanding that the problem is either the first CIA at U2, the 7406 at U8, or the clamping diodes. i've cleaned the power connectors and the serial connector with ISA and contact cleaner. do you know what the location is of the diodes i would need to check on this board? thanks and best wishes.
Where did you buy P6KE 6.8A? Mouser? trying to find a good supplier but most wanna sell in bulk it seems.
For most effective heat testing you should probably leave a game running that has some sorta animated title screen with music going. Just letting it run on the BASIC screen probably doesn't make it kick fully in.
You're right, of course! I would have to put some more stress on the ICs for proper temperature testing (and use a more accurate way of measuring as well...). This was just meant as a quick test to confirm that there's some heat dissipation at all through the new heatsinks.
Heard that the power supply is most fragile after this. For example putting 11 Volts at normal 5 Volt line. 😮
Yeah, those power supplies fail quite frequently and most of the times in a pretty violent manner resulting in overvoltage on the 5V line. The 9V AC line barely ever fails because it's basically just the secondary winding of a line transformer fed into the C64.
I'd like to do that to my C64c but it needs time/space I currently don't have. Oh, and skills too!
I think the C64c models run a lot cooler already and the chipset lasts way longer without doing anything so you can probably take your time. ;)
do you have a list of the parts you bought and where you found them? i would like to get some of those heat sinks
I don't have a real parts list included because the caps vary slightly depending on the C64 version you have. The heat sinks I used came from here: www.ebay.de/itm/8-Stuck-VGA-RAM-Kuhler-I-Cooler-Selbstklebend-Aluminium-Heatsink-/121997702605?hash=item1c67a135cd:g:eakAAOSwUfNXRqcZ
A very small fan inside the case would be useful to increase airflow through the heat sink fins.
I thought about that and did some research. Ray Carlsen (THE Commodore repair guru) argued that it's very difficult to place a fan inside these cases properly. In most positions, it would not really help the airflow at all. I haven't tried it because a fan just feels wrong to me but I'd say that it of course would help with the airflow if you put it anywhere near the vents.
There is some airflow if you remove the shielding (which I did after shooting this video) simply because the warm air rises through the vents on top and cold air is sucked in from the bottom vents.
Jan, is the camera tricking my eyes, or is the IR dot not centered on the actual chip surface for most of the measurements starting at 4:30?
+Wal Ter Your eyes and the camera are alright. This particular (cheap) IR thermometer needs you to point approx. 2 cm away from the point you want to measure at close range so it looks totally off. I basically aimed for the hottest spots though so I think I got it reasonably right.
Ah, interesting. I had no idea, now I wonder if my cheap IR thermometer (Rosewill) does the same.
Wat Ter, almost certainly, because the laser diode and the IR sensor can't both be physically in the same place. The collimation point can be couple meters away, and if you point at something closer or further away than that point there will inevitably be an offset.
Makes perfect sense.
Is there a way of adding a heatsink to the DIP chips that isn't so permanent? I'm reluctant to glue things to these old chips.
+fsphil I saw heatsinks that have a clamp that grips the ICs from underneath and presses the heatsinks on top. No idea where to get those, though. Plus you would have to get the ICs out to apply those.
It's not permanent, you can take them off with any plastic spudger or guitar pick.
What is the model number of the cheap IR thermometer with laser pointer you're using?
It's this one (BaseTech IRT 350): www.conrad.de/de/infrarot-thermometer-basetech-irt-350-optik-101-32-bis-350-c-1010133.html
Thanks.
wouldn't it be better to have the diode connect from the Positive to the PE... so that there would be no short circuit but the fuse would still turn off.
also is it just because its old or why does the Circuit board look like a wet book? 26:50
+Super Suchti That would probably work but you would either have to place the diode in a (modified to have a PE connection) power supply or run a PE wire to the C64 to do that.
The wrinkly circuit board results from the old school solder bath process these went through. It's perfectly normal for the old C64 PCBs. The newer board revisions look cleaner in that respect.
Where would I put the diode to make that mod on a ASSY 326298 Rev A 1982
?
Basically look for a location where the 5V rail is accessible and the tracks are wide enough to have some current going through them without burning. Ideally close to the power switch. I think the location will be quite similar to the one I've shown.
Hi Jan, ich habe leider bidirektionale Dioden bestellt. Es sind P6KE6.8CA. Funktionieren diese auch? Vielen Dank im voraus!!!!!
Oh, gute Frage. Ich habe gerade mal das Datenblatt überflogen und die bidirektionalen Dioden sollten sich bei Gleichspannung sehr ähnlich verhalten wie die unidirektionalen. Also ein vorsichtiges: „Müsste gehen!", aber komplett ohne Garantie mangels Tests. Die bidirektionalen werden wohl normalerweise bei Wechselspannung eingesetzt.
Danke für die Antwort. Habs heute verbaut, der C64 funktioniert noch. Übrigens mach bitte weiter so tolle Videos, ich verpasse keines!!!!!
Hello. Do you have links for the parts?
What is totally missed here is that a new-style chassis of C64C is actually cools the motherboard. Hot air gets up and sucks cold air into the case. Here how ventilation works
Great game...
I have to keep mentioning it because I love the whole thing so much (the game, the packaging, the love put into it...).
would it not be better to use that diode with a transistor to basicly cut off the power instead when voltage go to high, that way nothing get shorted and nothing blows
+ZyberWaX Of course it would be better to build something more sophisticated. This is only meant as a very crude last line of defense. It's the easiest way I know of to get at least some protection from overvoltage. If you want something more safe, I highly recommend bwack's circuit which works very safely and quickly.
One issue. When you were using the thermal sensor, that device has a laser pointer. If you watch the video, most of the time you were not actually pointing at the chip you were trying to get the reading on. The laser pointer was pointing at the circuitboard just beyond the chip or the chip just to the left of the one you were looking at...
Yup, that was intentional, actually. It's such a cheap thermometer that the laser pointer is not accurate when measuring things close range. It says in the manual to point it slightly away from the point you want to measure (I also took care to always point at the highest temperature spot I could find).
I would have suggested to check the heat at a high load, using the most powerful software possible.... it was nto even playing sound so I dont think the SID was even in use
That definitely makes sense for a more accurate test! I just did this as a very quick test to see if the heatsinks made any difference at all (which they did).
Is there any reason for keeping the rf modulator, if you never use it ? I would think that it draws a considerable amount of current and generates lot's of heat !! So...... Just remove the entire can, and use the space for other mods ! For instance, the dual SID board or a WiFi module, etc........! And, it would be less strain on the power supply !!
The video signal goes through the modulator circuit even if you use the composite output. There are modern replacements for the modulator but you can't just remove it completely because that way you'll get no video output at all. Jan explained it in the video too
could you please also show where I should install this on the shorter newer revision board?
Oh, I haven't done it on the shorter boards yet. Would have to look into it. There's another C64 refurbishing video coming up soon(ish) where I might cover it if I find a proper location.
Jan Beta, i found a nice location for it on the short boards. You'll see it at just a bit south-east of the modulator :-) it's a nice location.
Ah, I will have a look! Thanks! :)
Jan Beta here is a photo.
flic.kr/p/23m1P31
Some people have added small fans to the inside of their c64s. Sort of a shame, but definitely better for the lifespan.
Yes, probably good for a longer life but I tried to keep it as original as possible while still having some improvement considering heat. It would feel quite odd to me to have a fan in the C64 I think.
I don't think Noctua NF-A4x10-5V would look entirely out of place! At least the colour scheme isn't far off.
That's true. If I'd ever consider adding a fan to one of the old Commodores it would most certainly be a Noctua. For both the overall quality and the color scheme. :)
Anything to do to the board if the modulator is just removed?
Do you mean how to get video output if the modulator is removed? I'm not sure but I think you could get the signals from some of the connection points to the modulator and connect them to the A/V out directly. Was that even the question?
No, sorry for explaining it badly. Just wanted to know if I have to do anything if throwing the modulator out...
+dagrubar Ah, okay. That makes more sense. ;) I think you have to at least bridge some connections to get a video output if you remove the modulator. I found this forum thread about it (have not tried any of the methods suggested myself though): www.lemon64.com/forum/viewtopic.php?t=45330
My C64's don't have the crappy shield and I heatsinked the CPU and SID chips
+0Dark30 So you have the metal shield version? The cardboard one is really crap and does no good at all in terms of heat. I removed it altogether now.
It's the piece of junk cardboard shield
I would be interested in the temperature while having some CPU/graphics/sound/memory intensive software running - basically any modern demo would do just fine. :-)
I found it's not that much higher. The old ICs don't have a good energy management it seems. ;) I'll definitely make more (proper) tests sometime though. This was just to quickly prove that heatsinking the ICs has an effect at all.
These old chips don't have any energy management. Even when it's sitting in the Ready? prompt the CPU is giving its full effort to answering the very difficult problem of "did the user press a key? no. did the user press a key? no. did the user press a key? no. did the user..." several hundred times a second.
I put heatsink on my 286 12Mhz cpu, i dont understand why these PC were used without one because it gets too hot for touch.
To keep costs down as low as possible, maybe? This computer was built back in the day of the 'race to the bottom' in the micro market. This unfortunate machine was directly competing against something with icky rubber keys!
I'd also guess it's because of money. Aluminium and especially copper heatsinks cost a lot of money (well, at least it adds up for large production runs)...
It's a shame Commodore didn't think to use overvoltage protection
They were cost-reducing everything basically, unfortunately especially the power supplies... :/
26 comments, 29 likes. Come on people. You know you like it.
Haha, thanks. Go, go, go! :D
Thanks for that thorough explanation, are these the correct diodes to user for the power failsafe ?
www.amazon.de/gp/product/B07DHW491R/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
It doesn't really mention wether they are uni or bidirectional on Amazon.
Am I correct that you are using unidirectional diodes ?
Grube aus Belgien and stay safe !
Measuirng temp on PLA... we can see your laser wasn't even close to the chip!
Well spotted! That's actually due to the cheap infrared thermometer. It even says in the manual that when used for stuff that's close to it, the laser is going to point 2cm above the actual measuring point. I tried to find the hot spot in all the cases. Should really have switched the laser off as it's really irritating.
Caution: those IR temperature probes won't give accurate results if you point them at shiny, metal surfaces! Even the more expensive thermal imaging cameras fall victim to this!
Hi Jan. I would like to see a video of yours showing exactly how to add a fan, what to use with some links, where, etc, etc. I love your videos. I posted about your channel at EAB too, here: eab.abime.net/showthread.php?t=90615 . Keep on with the good work.
Oh, I'm not a huge fan of fans in the old hardware. Ray Carlsen (who is kind of the patron saint of all Commodore repair people) said in a statement that he fiddled around with adding fans into both the VIC-20 and the C64 and didn't find a reasonable way to do it. He says there's not enough vents in the cases to allow for much airflow anyway so proposes to add large heat sinks instead.
That said, I think GadgetUK did a video on adding a small fan to the VIC-II chip some time ago.
Thanks for the links (a lot of good channels in there)! :)
6.8V is a bit too much. It's better to use one of the many savers out there which will cut the power at around 5.4V. Here is a GadgetUK164's review of one of such savers (Bwack's). I'm using it myself. Works great with linear PSUs. For switching PSU it's better to use low ESR caps.
ruclips.net/video/znLTDw8OZRw/видео.html
Yes, I'm aware of bwack's brilliant C64saver. I actually linked it in the info-section of this video. ;) I know that the diode protection I did is only good for certain scenarios and as a kind of last line of defense. I'll definitely try something better in the future.
So 37ºC has to be nice now in those 35 years old VIC chips?. I've installed a fan there before they burn... I don't understand your futureproofing leaving such so hot componets that you can't even touch.
Um, you realize that 37C are human body temperature, right? It's not running all that hot.
Adding a fan probably makes sense for longevity indeed. I just tried to do something reasonable to prolong life without changing the system too much.
If you were at 37ºC you would turn a fan on in any case (for you I mean)...
But in fact other C= revisions I've seen in videos have the VIC running at 49ºC. I don't know the temperature of mine, but you wouldn't let the finger there with the heatsink only. Yes, I know it won't look original, but I think I better use a fan in my case.
I fail to see why you are replacing all the caps.you people on the net appear to have a phobia about caps going bad but in my years of electronic repair i have not seen a rash of modern caps going bad only the old 60s ones. Also i would add a lm7805 to that 5 v line
You could remove the card board :)
Probably a good idea. I'm always hesitant about these things because I try to keep it as close to original as possible. I think I'll end up removing it.
remove the cardboard it is unnecessary and causes significant heat build up :)
+Brian Jones Will do. I don't really know why I didn't remove it in the first place. Maybe my subconscious wanted to keep it "original". ;)
I look at it this way, the first ones didn't have it, it was added in later ones to pass FCC regs, so removing it makes it more original :)
+Brian Jones You're absolutely right. So it's actually closer to original without it in a way. Nice. ;)
ummm.... the laser points at what you are measuring... you never hit the SID, and before the SID you were actually on a RAM chip. Don't worry so much about what the camera picks up and just make sure of your aim.
We had this discussion before here in the comments. This infrared thermometer is a very cheap one and it says in the manual that if you are close to the object you want to measure you have to point the laser 2 cm above the object. I also aimed for the hottest spots so the measurements should be reasonably accurate.
wow, that is cheap. let me guess... it's a chinese one made in taiwan via korea... :P
menotu000, it's geometry. The laser diode and IR sensor can't physically both be in the same place, so there will be an offset due to that.
Hi Jan Beta. I'm making some mods in my C=64, and your suppressor diode to protect the 5V line has been discussed. I don't know if you have an account at EAB, but maybe you'll like to take a look at the thread where I'm making my mods: eab.abime.net/showthread.php?t=89997
why is he using tape? he should be using thermal compound!! thermal compound is better in my opinion
Oh, it's 3M thermally conductive tape. It's as good as thermal compound plus it's less messy to apply. (That said, I also often use a thermal glue to apply heatsinks to ICs which works just as well...)
oh.. ok. I'm not familiar of this... I'm used to paste. I'm fairly new to the repairing world and....well... you learn something new everyday. thanks for letting me know, I wish I had older computers like you do! keep up the good work!!!
The high pitched sound in this is making me sick. Can't keep watching unfortunately
Sorry about that! It's the CRT monitor running in the background. I'm too old to hear it myself actually. I'll try to filter it out in future videos.
I'm listening on logitech surround sound capable headphones and I can hear the high pitch. I'm in my 40's so maybe I can't hear it either.
I think the sound is at around 16kHz or so. It's very likely that people older than 25 years are not hearing it until its turned up VERY loud (if at all). ;)
www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/
I'm sorry but instant fail
Laser diode needs to be pointed at the thing you are measuring , in this case chip /processor , but you are measuring pins and motherboard and everything in between .
At first i thought OK, you are doing it for the sake of showing something on camera to prove a point, but if You want to appear professional You should at least be on point with your measuring and not waving around trying to get a reading - or this is a comedy part of the video that I'm missing ?
Appreciate the effort, but it only goes to a direction of proving the point that you actually don't need any equipment to make precise measurements and you can always work on a " feel " - and that is wrong.
I know You are starting up , but you need to improve on your way of presentations, and video needs to be precise with accurate measuring if you decide to film it for viewers they do need to see what You are measuring .
Idimi Dodjimi Are you sure he's actually missing the correct spots to measure? In this case the infrared thermometer is used at a quite short distance. If it's designed for measuring at longer distance, the laser could be a little off in this case.
Actually if you measure close objects with these infrared thermometers, you have to point the laser approx. 2 cm above the spot you want to measure. Even says so in the manual. That's what I did so it looks a bit odd. The values I get are quite accurate, I think.
Exactly right. It even says in the manual to point approx. 2 cm above the spot you want to measure if you are close to it.
Sure but you need to point instrument - laser diode to component you are measuring, and it should be measuring a focus point, in your case if you watch the video your pointer is all over the place, chip, board, chip legs etc... You do need a steady hand for it to work as intended.
Although i may be wrong here if that its not the point measuring device , and its near field measuring tool - which renders it useless in my point as I'm used to working with precise equipment that measures spot you aim for .
So will leave that as my mistake in the end.
Idimi Dodjimi It's a very cheap one so that's probably the problem with it. It clearly says in the manual to point a bit off the part you want to measure. I must admit that I didn't hold it very steadily because I was constantly looking to pick up the highest temperature of the chip I was measuring. Not very professional but in the end this was of course not about exact measuring but to see if these chips get hot at all and if there's a difference w/ heatsinks. Thanks for pointing that out, maybe I should have explained it in the video briefly. :)