TRS-80 Model 100 Capacitor Replacement
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- Опубликовано: 6 июл 2024
- My Radio Shack TRS-80 Model 100 has needed some attention for a while now. But in reality, all of these need serviced now due to failing aged parts. So in this video I go over the entire process of repalcing the capacitors in a Model 100 to get it working again.
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Every paper I turned in during four years of college were typed on my Model 100 and printed on a typewriter with a parallel printer interface. Before that my friends and I used a Model 100 to to break into the high school computer by tapping into the front office's phone line to steal the passwords. So many good memories.
Living a full life of crime, I see
Fun fact: The TRS-80 Model 100 was the last computer Bill Gates wrote code for.
He worked on the port of Microsoft Basic for it.....
@@dereketnyre7156 makes sense as it uses Intel 8085 CPU which basically still uses 8080 instruction set, so the original BASIC that Bill and Paul created would indeed run on these computers
You bought a computer bundle for the printer and you run a wiki about capacitors. Love it
I still want a Model 100 lol. They were the workhorse of journalists back in the day.
And network engineers through the 90s. Having a portable guaranteed to work terminal is hard to beat.
@@kurtwinter4422 I used mine for programming mobile satellite dishes from KVH.
@@kurtwinter4422 Yup, I had a battered Cambridge Z88, a very similar unit for some years for this very purpose!
Back when I had to lay capacitors on their own legs, I would strip out some wire and use the insulation from the wire around the legs of the capacitors. If you use silicone jacketed wire for the jacketing, it won't melt while you're soldering it. I love this kind of stuff, made my living for 30 years on it. I miss it, a lot.
Good repair and there's nothing wrong with bending the capacitor legs as you did to make it fit. I've done the same trick loads of time now. Although I tend to insulate the legs with some heat shrink tubing.
I had fun back in the day programming this machine at work.
Olivetti was also rebranding this. I was using this in a Physics lab. It was controlling an excimer Laser!
My dad loved his Tandy 102. He needed for all his business travel in the 80s. I think I remember him showing me the wonders of the copy-paste feature. When I brought it up recently he doesn’t remember it anymore. Interesting what we remember through life.
The Spectrum +3 also has the upsdie down chip mounting. I always found it fascinating, but it makes perfect sense.
used one of these as a packet radio terminal with a tnc2 while driving to Dayton in 83
Great job on the cap fix! All vintage electronics need this fix for longer life.
Love these repair videos. I haven't seen one of these little computers in a long time. A classmate had a pocket version in the early '90s and it was old then.
Wow, I haven't seen one of these in a very very long time.
Mani, I grew up on this stuff. RS Coco, PocketComputer, Acorn, Vic 20, C64, ZX81... you;re doing the good work. Thanks!
it was sold also by Olivetti in Europe but with a nicer chassis; it was called OLIVETTI M10, I used one in 83/84. The biggest difference was the screen on a hinge so you can get better visibility.
I lucked out and literally pulled mine from the compactor at the dump, the only issue I had was I had to take it apart and clean it and there's one line of pixels missing close to the top of the screen, but it works like a charm, full memory I added a Dial a rom and a Backpack from soigeneris its internal battery was fine, and it still has the name of the school it came from written on it in green sharpie,
I need to recap a few Mod 100s, a couple of Mod 102s, and two Model 200s.
Loved your video!
A friend had either an NEC or Epson which was essentially the same form factor. The HVAC guy at a place i used to work at used an Epson HX-20 to remote into our HVAC system. He liked using it over a laptop because of it's lighter weight than a laptop. Around 20 years ago i found a link to a surplus hardware site which carried "new old stock" systems like these. They were advertised as not having a power supply, but recommended one that would work. i look forward to see you using it as a serial terminal.
the hx20 and the tandy 100 were said to be some of the first 'laptop' machines
@@andygozzo72 The TRS was re-branded Kyocera Kyotronic 85. The Olivetti M10 and NEC PC-8201 were very similar in design.
@@timmooney7528 yep, i know their origins, i have a 100, a 200, plus a NEC PC8300 ,, i'd like to get the original Kyocera model sometime, if one turns up cheap enough!
I have one or two of these stashed away somewhere. I should dig it out and replace the caps...
This is the computer I started on. Learned BASIC on it. Used to get on BBSes with the built in 300 baud modem. Later bought a 1200 baud modem that was bigger than the damn Model 100. Still have mine. May have to break it out and replace the caps.
Speaking on the angle of viewing, if you notice on the back of it, there are two big holes in the top corners of the case. There are plastic legs that went in those holes to prop it up in the back.
I recall a friend in high school was showing one of those off somewhere between 1985 and 1987. He claimed that it rapidly drained the AA's when the modem was active.
I have a soft spot for these Tandy/Radio Shack machines. I think it’s great that a store chain decided to come up with their own range of computers!
My dad bought a TRS80 Model III when I was about 4 and that is the first computer I used. Nice to see this portable beauty working! I always wonder how practical they were in reality
Most TRS computer were rebranded machines. The TRS-80 model 100 shown here was a rebranded Kyocera machine (Kyotronic 85). The Pocket Computers were either from Sharp, either from Casio. Then Tandy 10 Business Computer was from ADDS. Even the Coco was not developed by TRS.
@@galier2 I know the TRS80 in this video is just a rebadge, but the Models I, III and 4 are definitely Tandy's own designs. And they were really very popular as well!
I love this little computer. Wrote some games in BASIC for it back in the day.
13:10 Bending capacitor legs directly at the cap may damage the seal. It is recommended to use needlenose pliers to create a bend just outside instead.
13:40 Like the post office says, "if it fits it ships". LOL
This video is a highlight.
You can put heat shrink on really long component legs like that funky cap to make sure it doesn't short out. Also they make adapter PCBs to let you mount a CR2032 where that rechargeable NiCad was, they have an integrated diode to prevent the battery from charging, and those batteries generally don't leak. You can also do a DIY thing with a diode of course.
While the F keys are offset from their labels on-screen, there is labelling on the glass (The [=1=] [=2=] in white) to show which label is for which key.
yea they should have drawn lines to the keys, that would have made it so much easier to not always make that mistake (which I still do).
It's funny this video popped up the day my RV A/C mega capacitor decided to start giving up.
It's a 320V 30 microfarad, quite bulky.
I still have a tape for one of those, but it was the one with a cassette. The school let me use it, but I had to buy my own tape.
I find the Model 100 still very useful as a portable serial terminal for accessing Cisco devices. Definitely something every retro-laber should have in there kit.
wow and yeah
Nice video; I have the pair RS100/Tandy102 and they are excellent machines! I did a recap on my RS100 a few years ago and replaced the battery with a NiMH - it could be an option for you.
One remark, though: the apolar capacitors can be created by a pair of back-to-back polar capacitors. For this application the increase in ESR will not influence the operation. (I did this on mine).
Excellent channel!
DVI connector below the rom. The Disk and Video interface allowed a monitor 80x25 24? And with a 5-1/4 drive
I drooled over these machines.
I have one of those for my 100. split the ribbon connector and taped it to the bottom of the computer. Put a dual row pin socket and connector on it so it worked just like the 102s connector. Made plugging it in much easier. Put 2 dsdd disk drives in it as well.
MJ
Sometimes you can find a SMD cap that is short and squat but with tab spacing able to be soldered onto the through hole pads.
I have a Model 100 2 NEC 8201s and an Olivetti. I even have the SuperRom for the Model 100 with a spreadsheet etc
The only other time I've seen SMD ICs mounted upside down like that is on the Sinclair (Amstrad) ZX Spectrum +3/+2A. It makes changing the chips out a royal pain in the arse (thankfully the ULA in these machines - the chip that was mounted this way - was far more reliable than on early units).
I used a TRS-80 model 200 to take notes while I was in advanced individual Training in the Army.
In case not yet mentioned there are two holes in bottom of case for feet. They were small pegs sold as an accessory
Nice video. Sometimes it is also a sort of weird glue under the capacitor. The metal parts can corrode then. I had that in a couple of IBM CRT’s. But a tip; Recap only if it is necessary. Or if you have spare time and want to do something fun :P
Hey Shelby, if you are still in contact with Ian, tell him we hope he's doing good.
i have one and its caps are perfectly ok, at least when i last opened the machine a couple or so years ago ....also got a model 200 plus one of its 'relatives', NEC PC8300... more important is to check/replace/remove that nicad.... the basic on the NEC is quite different in places, it has 'full screen' program editing, which the 100 doesnt, and it doesnt have the LINE statement, plus a few lesser differences
I kinda hate that they're shipping these caps in separate plastic bags with a huge sticker on the side. I mean the antistatic bags seem wasteful AND they're cumbersome to reuse because of the stickers. Yes, I know that information on the sticker is necessary especially if you are working in a lab/workshop and might need to order more (been there done that), but still.
Love the video though!
''(...) someone has even made a demake of Baldur's Gate III for it.''
Because of course they had to :D :D :D
Lovely little machine. Great video as always.
Bipolar for polar cap is fine. Just not the other way around.
Fyi, the "spokes on the ground pin" are called thermal ties.
Hey bro. That nicad battery is part of the (exceptionally complicated) reset circuit. Some of them don't power-on-reset reliably without it. But some do. It's weird.
I'd have given that board the Adrian Black treatment and scrubbed it in warm soapy water, just to be sure the electrolyte is completely cleaned up from spots like underneath resistors.
Those look like the LCD clamps with a finite number of twist cycles before they break off. Basically impossible to clean the zebra strips.
So I guess the capacitors is why mine still doesn't start up even after replacing the battery. Thing is, I'm not that good at soldering, certainly with the equipment I have at home; no desoldering gun, I have one of those spring-loaded solder suckers, and a RadioShack soldering iron with the circular tip and the squeeze bulb extractor. My wife says "then you should sell it" (even though I only just bought it last year).
As strange as it may seem, our local Apple Club's secretary used a TRS-80 Model 100 to take the minutes of the cub meetings on back in the 80s and 90s.
MJ
I had a similar computer that had a detachable printer and it was manufactured by Epson.
I have one of these, but the previous owner left some AA batteries in it and they leaked all over... I got everything cleaned up except the destroyed contrast potentiometer 😞
Everytime this thing is mentioned I just end up wanting to play TIS-100
I had a parallel port printer hooked up to the parallel port and a serial cable hooked up to my desktop that had a bad parallel port temporarily once. I used the telcom program to echo everything on the serial port to the parallel port. I told my Windows 98 machine to switch the port the printer was supposed to be on from parallel to serial. The Model 100 was able to translate the serial signals to parallel so I could print to my laser printer. It was a little annoying because some of those commands would cause the Model 100 to beep, but the printer had no issues. This was temporary until I got my parallel port fixed.
For the missing lines on the screen, if wiping the zebra strip with a dry cotton cloth doesn't work (I have never found a cleaning chemical that doesn't damage a zebra strip) try reversing the strip left to right, or putting it back in upside down. You might move the bad conductive part to a new location that happens to miss a connection and rests on the insulating part of the board. I still have mine and I need to pull it out of mothballs and get it running again.
It doesn’t just have character graphics, it has full addressable pixel graphics.
I like to replace those Ni-Cd barrel batteries with Ni-Mh versions. A bit more expensive, but it keeps the original footprint, they CAN be recharged, and best of all, they don't leak!
actually NIMHs definitely do leak, i've seen it a lot and had machines ruined by them...
Next up: put a paper tape below the screen and draw lines connecting it to the function keys 😉
hey, I got one of those, I still prefer my HX-20 to it, but the screen is nice, and there is more software for it. I'd prefer to have a 102, and the keyboard on this is not as good as the HX20. Now you just need a REXCPM, and a BPD+. If you want some more ancient laptops to fix, I have at least one hx-20 that I kinda frankensteined with a mh-cd42 that needs its serial port re-traced, and a PX-8 that needs some love. I have two other HX-20s that work, so I'm not too worried about the serial port. anyway, Hi from Tempe!
if you think removing caps on that was bad... try on an og xBox, i've got 6 of them that I need to re-cap and i've been putting them off because of the dang ground plane those daft things have... and they have at most 33 caps that's a mix of both thru hole and smd
From memory there was a PSET command to set individual pixels?
I have one of these and would love to get printing working, if possible. How does one connect a dot matrix printer to this, you mention a special cable…is that even available anymore? Thank you in advance!
SMD chips mounted on top of ceramic DIP packages?
Seems very early for SMT components but I really don't know.
He bought Goodwill yellow.
Heat-staked?
That's the term I've always heard
The technical terms when a capacitor does that is called:
Capacitor vomit
or
Capacitor diarrhea
One of my first computer jobs was writing software for NASA to run on one of these
I wonder why an external video port, composite, was not added.
That was on the video disk interface giving you up to 2 5.25" drives and composite video.
MJ
RIP bad line
Can it run doom?
Are there textadventure games for these computers?
I have a 1985 vintage Model 200 and its is not yellowed at all - rather shocking to see this specimen of Model 100 so yellowed.
a laptop from before laptops 🙂
Aw man I bought one on ebay "as is" and the batteries ate about 1/3 of the PCB, it's covered in bright blue/green crust.
Probably still salvageable with a lot of patience since the schematics are available and ICs tend to be spared from permanent internal damage from leaky batteries.
It not using custom ICs is another bonus if things do have to be replaced anywhere.
@@oliverer3 Lots of eaten traces and IC pins, it's kinda awful, and I don't have the time these days, maybe in winter
1:39 hmm. I don't care for printer ports either.
The most infuriating thing about this machine is that although it has a RAM filesystem, the MS BASIC implementation doesn't have random access files. >_
Anyone else want a techno track with that desoldering gun?
Not replacing the battery? I'm sure the EverReady people are coming to CHARGE you with breaking law CR2032 for having NEGATIVE thoughts instead of POSITIVE thoughts on battery replacement! 😸 At least you could have let the comment section VOLT on replacement. 🤣
No vacuum pump on your desoldering tool? What is that thing?
I seem to recall from the video in which Shelby talks about his tools that the pump is in the base-station
@@HrLBolle I'd still expect to hear it, just perhaps not as loudly as the guns with the pump integrated into the handle.
@@AndrewFremantle check the video on his tools
It pulls vacuum with compressed air. No pump because the air tank is full
Huh. It's a Metcal MX-DS1. Needs both a Metcal soldering base station *and* an air compressor. Looks super neat, but given I have neither of those things that's not going on my shopping list anytime soon.
Dude when you bent the capacitor like that, you should’ve put heat shrink on the legs to protect them from shorting…😒😒😒
Just a rarely what I could do…
This is the dryest, most boring content possible. I love it so much
Best American