BTW - My 65XE MMU worked in this board! As does the NTSC ANTIC and my Sally and OS ROM. You would run into timing issues using the NTSC ANTIC with games and stuff though (probably).
Here is an interesting story about MMUs! Yesterday I finished repairing(3 bad MT RAMS) and putting sockets on a Atari 800xl board(PAL). It booted ok but it randomly kept crashing(after few seconds to even hours!). Long story short the system stop crashing after inserting an MMU from an 65xe(PAL). The funny part was that the "bad" MMU works fine on the 65xe!!!!? I am puzzled by this...any ideas?
You can use NTSC chips in a PAL Atari 800/XL/XE machine. The opposite doesn't work nearly as well. It's a common trick to put an NTSC ANTIC into a PAL machine for NTSC timing/compatibility, etc..
I like the honesty in vids like this, someone else could have easily cut out the bits where "our survey says... X" then pretended to say they socketed stuff up for possible upgrades and future servicing blah blah. But instead you carry on as you are with the funny annotations and stuff. Hope you are doing good Gadge. I had an XE as a kid I don't mis it one bit lol. Thanks for the vid :)
We are having to deal with some stuff, and the wife's issues are being a dick, but otherwise plodding along as usual :) I hope you are well too bud. Respect.
Im back here watching this again! Got an 800xl here that boots to black screen. On initial switch on i get a flash of colour either red yellow or blue then blackness. I just replaced delay line chip and no difference. All voltages at 5.1 and present. Antic Gtia both roms warm. 6502 warmer. Ram all cold. I dont have a probe! High time i got one.
That transistor you replaced drives the CADJ (color adjust) pin of GTIA from the phi1 clock generated by Sally, and the trimmer adjusts the delay from phi1. What that does is keep the color clock in sync with the dot clock, which GTIA then delays to set the hue of the current pixel, so if that transistor is dead the colors will drift around as you saw.
Sorry but that simply isn't the case. The original 400/800 machines ran the DEL/CADJ pin from +12V through a resistor and trimmer pot. Since +12V is absent on the XL/XE boards Atari chose to use the unused Φ1 clock to drive a didoe pump circuit, consisting of Q1 a couple of diodes, resistors and capacitors, to generate sufficient voltage to allow enough adjustment range from the +5V supply. The trimmer pot does nothing other than control the DC voltage being supplied to GTIA pin 17. Period.
Always fun to see you so deep in discussion with yourself Chris :) Very entertaining and love to see the Atari800XL on the table. I know next to nothing about it (especially the disk rom and bios stuff) so it's a learning experience as well. Hope you're well Chris. Your pedicure looks amazing as ever.
58:40 best way to install a Sophia is to use the 3D printed PBI adapter with an HDMI plug. This way there's no need to damage or change the case. He'll need a longer internal cable that will reach PBI from GTIA but those might be available now. I prefer the real GTIA than an emulated or FPGA.
Excellent work, mate. Thank you. I have a real soft spot for the Atari8Bit range. I guess because it dates back to the '70s (as I do!) but also because it wasn't hugely popular here in the UK, and always comes across as a little exotic. This machine is going to get accelerated with a Rapidus accelerator, to see how far she can go!!
Thanks Will =D It was a pleasure to work on it for you! Hopefully it works when you get chance to test! Yes, I agree - it was pretty rare over here and there's something cool about how the games look and sound on it. I love my 65XE =D
Great job Chris. We have all been there with the diagnosis of faults trouble shooting isnt always easy but it is easy to get side tracked. Great video thank u.
So we now have buzzer jump scares to keep us on our toes... =) Can't wait to see what is inside the delay line. I have one on a ISA memory expansion board that a pin got broken off but was luckily able to solder a replacement leg onto the remaining stub and the card did still work afterwards.
The delay lines might be like those on a color CRT, but it’s probably a SAW (Surface Acoustic Wave) technology, which is sort of like a laser-trimmed piezo-buzzer that operates at a much higher frequency. Conceptually, it’s like a reverb tank in a guitar amp with vibrato (or is it tremolo? I always forget); you pulse the input, then - after a delay based on physical properties of the material - an output pulse comes out. One thing that might work, is getting the PLA (or is it the Vic chip?) chip from a C64 to generate the RAS/CAS for this machine, and put it on a daughterboard that’ll plug in where the old delay line IC (?) went. And those are a lot easier to find than that delay line.
9:02 That's a NOR gate, not an OR gate. The little circle on the end means that the output is inverted. If any of the inputs are high, the output will be low.
What a fantastic ride. It helps a lot to follow the paths you take doing diagnostics. Those dead ends give very useful information for the problems we might find. I actually have an 800XL myself from back in the day, sitting in its box waiting for attention. I´m almost finished making an Arduino S-Drive to load those sweet games I never had as a kid. Shortly after buying it, the only store in my province that sold it dropped entirely the brand, so I was stranded with a few tapes and a single cartridge, and I never, ever, knew another kid with Atari here to share thins (Spectrum and MSX were the absolute kings) Anyway, I want to have it running again, but I am terrified about powering it ON after maybe 25 years stored. I did that with my old 386 and it went very very very bad. Do you have any advice to power old devices beyond testing the power supply before?
There's not too much that could go wrong with the machine itself. Just make sure the power brick actually still outputs 5v before you switch it on as those tend to go bad and can indeed fry the machine. It would probably be good to replace it eventually. Technically a decent USB wall wart would do just fine instead. It sure can be fun getting into these systems. Atari XL has a decently active community and quite some upgrades are still being made.
Some people still use film cameras. My son has a Fuji 35mm model with multiple lenses and he finds the whole process of composing the image, shooting and then getting it developed fascinating. Not everything retro has to be Computing Hardware! 😉
This made me think of the Acid 800xl, perhaps you should have just removed everything and replaced like I did haha. I still have the other 800xl that was donated for parts, it was working, but I checked last week and it has a blank screen and I noticed the voltage drop so I should take a look at this one. Also have a 65xe board that was stripped of most parts and a case for it.
Yo chris..... in an amstradian....and your a cooomadorian.... can you use the old woody 2600 console carts on these..? excellent vid as always...:) N x
The system boots by OS and then checks for the presence of a cart before handing control over to the cart. The cart cannot run on its own, it must be detected and qualified by the OS.
I was screaming 'delay line' the whole time, but you somehow didn't hear me...😉 You said something about every chip in that area, but completely neglected the poor delay line chip. That said, I really don't like this chip with it's reduced pin count. That causes it to sit quite loosely in its socket.
YES 9:27, I was waiting for pokie pokie tappie tappie with the screwdriver. When I saw it in your hand in the beginning of the video, I said YES POKE IT!!! lol ♥
BTW - My 65XE MMU worked in this board! As does the NTSC ANTIC and my Sally and OS ROM. You would run into timing issues using the NTSC ANTIC with games and stuff though (probably).
Here is an interesting story about MMUs! Yesterday I finished repairing(3 bad MT RAMS) and putting sockets on a Atari 800xl board(PAL). It booted ok but it randomly kept crashing(after few seconds to even hours!). Long story short the system stop crashing after inserting an MMU from an 65xe(PAL). The funny part was that the "bad" MMU works fine on the 65xe!!!!?
I am puzzled by this...any ideas?
@@nickolasgaspar9660 Could be the 65XE socket (you installed one?) makes better contact with the IC. Did you deoxit the IC and sockets?
You can use NTSC chips in a PAL Atari 800/XL/XE machine. The opposite doesn't work nearly as well. It's a common trick to put an NTSC ANTIC into a PAL machine for NTSC timing/compatibility, etc..
I like the honesty in vids like this, someone else could have easily cut out the bits where "our survey says... X" then pretended to say they socketed stuff up for possible upgrades and future servicing blah blah. But instead you carry on as you are with the funny annotations and stuff. Hope you are doing good Gadge. I had an XE as a kid I don't mis it one bit lol.
Thanks for the vid :)
Thanks mate =D Hope you and the family are well!
We are having to deal with some stuff, and the wife's issues are being a dick, but otherwise plodding along as usual :) I hope you are well too bud. Respect.
@@Neffers_UK Same here - having major problems and stress like I've never experienced in my life =/ Hope everything improves for your wife soon =D
Love these super long videos. Being stuck at home as an unpaid carer for a family member these videos help keep me sane.
Im back here watching this again! Got an 800xl here that boots to black screen. On initial switch on i get a flash of colour either red yellow or blue then blackness.
I just replaced delay line chip and no difference. All voltages at 5.1 and present.
Antic Gtia both roms warm. 6502 warmer. Ram all cold. I dont have a probe! High time i got one.
Im glad you went the long way around! Much more informative and entertaining! Love it.
That transistor you replaced drives the CADJ (color adjust) pin of GTIA from the phi1 clock generated by Sally, and the trimmer adjusts the delay from phi1. What that does is keep the color clock in sync with the dot clock, which GTIA then delays to set the hue of the current pixel, so if that transistor is dead the colors will drift around as you saw.
Sorry but that simply isn't the case.
The original 400/800 machines ran the DEL/CADJ pin from +12V through a resistor and trimmer pot. Since +12V is absent on the XL/XE boards Atari chose to use the unused Φ1 clock to drive a didoe pump circuit, consisting of Q1 a couple of diodes, resistors and capacitors, to generate sufficient voltage to allow enough adjustment range from the +5V supply.
The trimmer pot does nothing other than control the DC voltage being supplied to GTIA pin 17. Period.
Always fun to see you so deep in discussion with yourself Chris :) Very entertaining and love to see the Atari800XL on the table. I know next to nothing about it (especially the disk rom and bios stuff) so it's a learning experience as well.
Hope you're well Chris. Your pedicure looks amazing as ever.
Thanks =D And 🤣 at the pedicure!!!
58:40 best way to install a Sophia is to use the 3D printed PBI adapter with an HDMI plug. This way there's no need to damage or change the case. He'll need a longer internal cable that will reach PBI from GTIA but those might be available now. I prefer the real GTIA than an emulated or FPGA.
Excellent work, mate. Thank you. I have a real soft spot for the Atari8Bit range. I guess because it dates back to the '70s (as I do!) but also because it wasn't hugely popular here in the UK, and always comes across as a little exotic. This machine is going to get accelerated with a Rapidus accelerator, to see how far she can go!!
Thanks Will =D It was a pleasure to work on it for you! Hopefully it works when you get chance to test! Yes, I agree - it was pretty rare over here and there's something cool about how the games look and sound on it. I love my 65XE =D
That piece of tape with the smilie on it is factory insulation for the top metal bracket for the expansion port.
Great job Chris. We have all been there with the diagnosis of faults trouble shooting isnt always easy but it is easy to get side tracked. Great video thank u.
Great vid, loved the family fortunes vibe & that transistor would have driven me potty.
So we now have buzzer jump scares to keep us on our toes... =) Can't wait to see what is inside the delay line. I have one on a ISA memory expansion board that a pin got broken off but was luckily able to solder a replacement leg onto the remaining stub and the card did still work afterwards.
LOL
Loving the on-screen comments as you work through it; makes it really interesting and it makes us realise we are not alone :-)
The delay lines might be like those on a color CRT, but it’s probably a SAW (Surface Acoustic Wave) technology, which is sort of like a laser-trimmed piezo-buzzer that operates at a much higher frequency. Conceptually, it’s like a reverb tank in a guitar amp with vibrato (or is it tremolo? I always forget); you pulse the input, then - after a delay based on physical properties of the material - an output pulse comes out.
One thing that might work, is getting the PLA (or is it the Vic chip?) chip from a C64 to generate the RAS/CAS for this machine, and put it on a daughterboard that’ll plug in where the old delay line IC (?) went. And those are a lot easier to find than that delay line.
9:02 That's a NOR gate, not an OR gate. The little circle on the end means that the output is inverted. If any of the inputs are high, the output will be low.
Thanks, yes - I mentioned that in the live chat text to the right side (when it premierred). =D
Where did you get the Polish replacement part from? I have an 800xl doing exactly the same and I'd like to replace this part first.
www.ebay.co.uk/itm/125097401743?hash=item1d2062dd8f:g:B-IAAOSwNgVgqpJl
Great fix, the Atari 8-bits are such cool systems. Thanks for posting!
Thanks Adam =D Have a great Christmas and Happy 2022!
What a fantastic ride. It helps a lot to follow the paths you take doing diagnostics. Those dead ends give very useful information for the problems we might find.
I actually have an 800XL myself from back in the day, sitting in its box waiting for attention. I´m almost finished making an Arduino S-Drive to load those sweet games I never had as a kid. Shortly after buying it, the only store in my province that sold it dropped entirely the brand, so I was stranded with a few tapes and a single cartridge, and I never, ever, knew another kid with Atari here to share thins (Spectrum and MSX were the absolute kings)
Anyway, I want to have it running again, but I am terrified about powering it ON after maybe 25 years stored. I did that with my old 386 and it went very very very bad.
Do you have any advice to power old devices beyond testing the power supply before?
There's not too much that could go wrong with the machine itself. Just make sure the power brick actually still outputs 5v before you switch it on as those tend to go bad and can indeed fry the machine. It would probably be good to replace it eventually. Technically a decent USB wall wart would do just fine instead.
It sure can be fun getting into these systems. Atari XL has a decently active community and quite some upgrades are still being made.
Some people still use film cameras. My son has a Fuji 35mm model with multiple lenses and he finds the whole process of composing the image, shooting and then getting it developed fascinating. Not everything retro has to be Computing Hardware! 😉
=D
If you didn’t know, the delay line chip is actually just a 74LS14 chip with the outputs slightly modified
Thanks for the info there =D
Interesting defect. Always wondered what that weird chip in the middle was :)
Can you tell me what logic probe you are using:-) ?
It's quite an old one - sold by RS Online. It's probably 40 years old now though!
This made me think of the Acid 800xl, perhaps you should have just removed everything and replaced like I did haha. I still have the other 800xl that was donated for parts, it was working, but I checked last week and it has a blank screen and I noticed the voltage drop so I should take a look at this one. Also have a 65xe board that was stripped of most parts and a case for it.
Yo chris.....
in an amstradian....and your a cooomadorian....
can you use the old woody 2600 console carts on these..?
excellent vid as always...:)
N x
No, I don't think so =/ I believe the 5200 carts work on the Atari 8bits though...
@@GadgetUK164 Ta for that..:)
(@18:31) -LOL! 🤗 Hey, at least the IC is socketed, now. Glass half-full, and all that. 😏
MMU is a generic PAL16L8 chip... it may be easily replaced with a GAL16V8 if needed. Equations are known and available.
Thanks, yes - aware of this! Already had a number of .jed files for this one!
The system boots by OS and then checks for the presence of a cart before handing control over to the cart. The cart cannot run on its own, it must be detected and qualified by the OS.
I was screaming 'delay line' the whole time, but you somehow didn't hear me...😉
You said something about every chip in that area, but completely neglected the poor delay line chip. That said, I really don't like this chip with it's reduced pin count. That causes it to sit quite loosely in its socket.
😁
YES 9:27, I was waiting for pokie pokie tappie tappie with the screwdriver. When I saw it in your hand in the beginning of the video, I said YES POKE IT!!! lol ♥
🤣
I have 3 and one modified to 256k. good video
У меня была ситуация с красным экраном. В итоге я обнаружил, что процессор и одна микросхема памяти плохие.
Спасибо за информацию!
Haha! Family fortunes sound fx! :-p
Beau travail ✌️🕹
Paul Daniels had a Atari 800
Some people like that! Not a lot!
They all had the tape
The important thing is to keep a balance.....and your wii fit board verifies that! lol
LOL!!!
You said ... Our survey said .... lmfao. Great vid
=D