[RESOLVED] Trying to fix my Atari 2600 :/

[RIP-Felix]

Anyone out there who has fixed an Atari 2600?

     I haven't cleaned the board yet. I'll try that to see if the dark crud around the PWR switch is just flux that never got cleaned off. If not, I wonder if I can try scraping the trace and soldering over it to reestablish a connection. I'll test with the multi-meter after I clean it to see if it's broken, otherwise I may have to try this. I've read the Atari can handle voltage over 9v, but I don't know if that 15v reading is normal or due to a fault and way too much for the Atari's over-voltage protection to handle. Does this board look fixable, or do I have a fried egg? If so, this may be my next MiniITX case and GameEx rig

[stigzler]

15V on a 9V system doesn't sound good. However, 80s electronics are built like tanks, so who knows!? Easiest way = buy a cheap 9V PSU from ebay (better still, a variable for future projects!) and give her a go...

Of course, you are just looking for and excuse to call it dead, right, so you can start modding that case..

[RIP-Felix]

It looks fried to me, but If I can get it working again I would like to keep it. If not, then it's a future modding project candidate for sure. Like yours maybe! I'm looking at a light sixer on ebay at the moment, says it working ($35). I might take a chance on that, I like the look better than the four switch anyway. I wish people would take them apart and provide pics of the motherboard traces...lol. Not going to happen!

***EDIT***

I went ahead and bought a vader black 4 switch on ebay ($50 shipped). It was a decent price, compared to other listings, and the company looks legit; they will refund it if doesn't work. So I guess that means I can use the fried? one for a mod. I'll have to give it some thought. I still might try fixing it.

[ClassicGMR]

Wait until the vader comes in. Use that PSU to test this Atari. These things are indeed tanks and very rarely fail. You may have to clean the switches for better contact but the boards themselves - and most of the chips - don't care if it's been in a barn for 30 years...

 

Best guide for cleaning a 2600:

http://atariage.com/forums/topic/184296-slowcoders-guide-to-cleaning-up-your-2600/

[stigzler]

I love those Sears replicas. Sadly - you never see them come up here in the UK.

[RIP-Felix]

21 hours ago, ClassicGMR said:

Wait until the vader comes in. Use that PSU to test this Atari. These things are indeed tanks and very rarely fail. You may have to clean the switches for better contact but the boards themselves - and most of the chips - don't care if it's been in a barn for 30 years...

 

Best guide for cleaning a 2600:

http://atariage.com/forums/topic/184296-slowcoders-guide-to-cleaning-up-your-2600/

Thanks for the link, I found a few guides, but that one is indeed top notch.

     I cleaned the board today with 70% isopropyl alcohol, I have a liter spray bottle of the stuff (Very useful to keep around. Did you know you can spray roses and other plant's leaves to kill scale and aphids? And it's nice for the occasional electronics project too;). Anyway, the contacts looked much better. The dark scoring was indeed crud and came off. All the winked traces are still there, but I'm not sure if that was due to 1980s manufacturing process, or has happened since. I have seen similar wrinkled traces in pics of other motherboards, so maybe that's normal. Sorry no pics. I tested with a Multimeter and was able to get continuity all around the board's common layer. The power switch's line appeared contiguous. I went ahead and re-soldered the PWR switch and the Barrel jack contacts adding a bit of new (leaded) solder. That should ensure power is getting to the board. I confirmed good continuity with the multimeter. I also went at the RCA connector and switches with fine sand paper to knock the corrosion off. I tested the RCA with my multimeter and confirmed continuity. So the Atari has power and a good signal out now. I inspected all the caps and other components carefully and didn't see any obvious signs of damage. No bulging, scorching, leaking, unseated chips, or broken solder joints. I'm feeling better about it's chances of survival now!

     I gave the case a bath and dried everything. I put it back together and I'll let it sit until I get the other one in so I can test it with a working Power supply. I'm not plugging it in until I test the voltage. I'm not trusting 37 year old AC/DC adapters ATM. Damn has it been that long? lol! One thing I haven't done yet, because I just found that link @ClassicGMR linked, is open and clean the switches themselves. I'll have to open it again, but oh well. I'd Better do it right! Although I didn't buy it for this purpose, I do have some Super Lube Silicone Lubricating Grease. It says it has High Dielectric strength and is thermally stable. I think it will work fine for coating the contacts in the switches. I originally bought it to lubricate the guide rods on my 3D printer. It's a huge tube, I'm kinda glad I've found another use for it. Off to it then...

[ClassicGMR]

Last time I tore down a 2600 I bought a can of this for $4.77 to clean/lubricate the switches and they're beautiful now:

https://www.walmart.com/ip/CRC-Electronic-Cleaner-11-Oz/16817418

 

EDIT 1: FYI the adapter does need to be 9v however, unless you're playing the Supercharger add-on or plan to do a video mod which may require the amperage, the 500mA rating can go as low as 300mA. Anything below that and you'll see color distortion. My adapter is actually an aftermarket that is 9v 300mA. I didn't realize this until tonight and will probably opt to replace it because I like my wireless controllers and THAT uses the original PSU. Might be the source of interference/sporadic fluctuations I'm getting.

 

EDIT 2: I was reading up on power adapters. According to the techies on AtariAge the Atari power supply (or ANY power supply) not under load will read significantly higher output. So there may actually be nothing wrong with your adapter there. Check out post #13(BigO) and #14(Benzman66) specifically.

http://atariage.com/forums/topic/180566-2600-power-supply-n-stuff/?p=2260553

Edited August 15, 2017 by ClassicGMR
Added EVEN MORE info

[RIP-Felix]

17 hours ago, ClassicGMR said:

EDIT 2: I was reading up on power adapters. According to the techies on AtariAge the Atari power supply (or ANY power supply) not under load will read significantly higher output. So there may actually be nothing wrong with your adapter there. Check out post #13(BigO) and #14(Benzman66) specifically.

http://atariage.com/forums/topic/180566-2600-power-supply-n-stuff/?p=2260553

Hmm...post 17 mentions that the Atari voltage regulator can accept anywhere from 8-35V DC and that the adapter will read significantly higher when it's not under load! If 13-14V is normal, I guess that the 15V I was seeing was probably fine. Weird, but okay, maybe that wasn't my problem. Maybe I'll try it again now that it's all cleaned. Who knows, maybe the power contacts were too dirty or the RCA was unseated. Let me plug it in and see if I can't get it running (Crossing my fingers). I'll edit back with the results...

***EDIT***

No dice . Dang, I thought maybe it would work. Well I don't know. I thought maybe it's the RCA to antenna adapter I have. I had another Coaxial to 2-prong antenna adapter. So I tried putting that on the end of the RCA adapter, but it was even looser than the first. Maybe the Atari is outputting a signal, but the adapter is busted, IDK. I don't have another one to test with and haven't used it for anything else since the Atari stopped working. I guess I'll keep looking at guides for ideas of things to try while I wait for the 4-switch "Vader" to get here.

[RIP-Felix]

Getting more proactive:

Question 1: Does the board have power?

Okay, proof that the board is getting power. Load test does indeed drop the Voltage to what I've read is normal. So it's defiantly not the adapter, whew!

Question 2: Is the Voltage regulator working?

The Voltage regulator is receiving and outputting the correct voltages. So that part is good too.

Spoiler

 

That video led me to this video series. Yes...YES...YES!!! Skip to 2:35 for the relevant section.

 

Question 3: Is the Signal getting to the TV?

     I don't know. It's not when I plug it in strait up. Is the adapter sunk? Maybe, I don't have another to test with. I should go to the local used junk store (Goodwill) to see if I can pick one up.

That's where I currently am...off to research more...

[ClassicGMR]

When you had the system torn down did you reseat the RF cable inside on the main board? Was it loose or frayed? Mine needed replacement as it did output video but was getting a lot of static. Turns out the connector was coming loose from the wiring itself.

(You probably know this part but just in case) When you connect to the tv using the switchbox are you on the correct station? The Atari has a 3-4 switch. If you're in an area that transmits on 3 then you may want to try channel 4.

Also - these are AWESOME. Switchboxes can easily be bypassed now. Just FYI.

https://www.ebay.com/p/Atari-2600-RF-TV-Coaxial-F-Plug-Female-Adapter-Third-Party/691164204

[tthurman]

20 hours ago, ClassicGMR said:

ast time I tore down a 2600 I bought a can of this for $4.77 to clean/lubricate the switches and they're beautiful now:

https://www.walmart.com/ip/CRC-Electronic-Cleaner-11-Oz/16817418

 

Thanks, I'll add this to my CAIG collection of cleaners!

 

[RIP-Felix]

Ok, I found something! As I've been watching that service guide from the 80s I've narrowed it down. I don't have an oscilloscope (at work I have access to one), so checking clock and reset circuit health is more trouble than I care for at the moment. However, he said if it's not the adapter, voltage regulator, capacitor/resistor circuit, then it lies in the chips (CPU, TIA, and/or PIA). But before assuming they're bad to check the solder joints carefully for faults. That's when I spotted this:

I'm currently looking up the pins on the schematic of that chip to see what they are. I cant imagine that is supposed to be there. I can't  imagine it would have left the factory that way, but this is an old board I picked up at the Goodwill years ago. Who knows what had been done to it before I got it. Still learning more, I'll edit back later...

***EDIT***

OK that it the Television Interface Adapter (TIA). From this teardown site I can see the revision 13 board's backside very well (Mine is revision 14, so the two are very close):

     It's the bottom row of solder pins. See, no bridging. Something else I've noticed is that the board above has the same wrinkles in the traces! I thought they might be bubbling from melting down my board, but it looks to be a byproduct of the manufacturing process. So that's one mystery solved, and it's a relief.

     The TIA chip is tasked with converting the digital image to output analog (Color, Sound, and sync). That may very well be why I get no video signal at all. Just plain dead. No black screen. No flickering. No sign that anything is being sent out at all. That's why I originally suspected the PWR circuit, but now I suspect that part is fine. It may just be this chip, assuming the bridge fried it. But who knows, it might work if I just fix fix that bridge. At least I've found a direction! Still learning, I need to see what those pins are. Off to it then (this project is fun)...

***EDIT***

Okay, I think I found my answer. It's not what I was hoping, but it's interesting non the less.

Pins 12 and 13 are supposed to be bridged in the NTSC version. If I desolder them, then I would essentially be making a PAL motherboard, I don't know if sticking a PAL chip in it would work, if that's all I could find, but it's an intriguing idea...LOL. The picture from the teardown must have been a PAL board. Rats, I thought I was on to something.

[ClassicGMR]

Nice catch on that short. Not sure where that came from but, yeah, I'm pretty sure it doesn't belong there. Time for a solder braid!

Only thing I can think of is maybe a power surge hit the TIA which lead to the solder bridge. That's one weird place for a short though. Also explains why it may have been donated to Goodwill.

[RIP-Felix]

2 hours ago, ClassicGMR said:

Nice catch on that short. Not sure where that came from but, yeah, I'm pretty sure it doesn't belong there. Time for a solder braid!

Only thing I can think of is maybe a power surge hit the TIA which lead to the solder bridge. That's one weird place for a short though. Also explains why it may have been donated to Goodwill.

Check my edit, it's not what I was hoping.

It's weird where projects like this take you. I found the following video. Hardware based handheld Atari 2600 mod, Interesting. Actually there is a useful diagnostic tool at 22:05 I was excited to find. It should allow me to see a voltage High signal on the CPU A12 pin if the cartridge Rom is being accessed. I was wondering since I can't verify the cartridge is working, without video or sound. So I have no idea if the game is actually running. If after turning on the system and A12 stays low (Under 2.4v) then I know it's not getting that far. Kinda fun, I'm really learning the ins and outs of my 2600! Nerd manna:

Part 1:

Spoiler

 

 

Part 2:

Spoiler

 

 

[ClassicGMR]

Well you've gone beyond anything else I can help with. Keep me informed though. I didn't even know about the PAL/NTSC bridge.

Ben Heck is awesome. I wish I still had the VCSp 5 he made for me for PhillyClassic. Some ^%$#ing idiot(me) sold it.

[RIP-Felix]

Going Deeper

After work today, I stuck around and made use of an oscilloscope to test further.

This video helped me immensely:

Spoiler

 

I watched all 10 parts, but this part was what I checked today.

Okay, following his methodology:

Symptom: Dead unit. It's not sending any video out. I don't get a black screen, it just shows the static like hadn't flipped the on switch.

4 step Test Procedure:

1. Power circuit: With a multimeter I have previously confirmed it's not the power adapter or voltage regulator. I inspected and soldered all cold solder joints (Those I suspected might be). I cleaned the board thoroughly and reseated the chips.
2. CPU Clock (Oscillator):
   Spoiler

   

   I could not get the 3.58MHz on the CPU clock (pin 27) mentioned in the video, but everything else looked good. That's where 21:10 - 22:47 of this video is helpful:

   He explains the clock circuit a bit better and clears up what frequency I'm supposed to be seeing from Pin 27 on the MPU/CPU. Basically the crystal oscillator generates a 3.58MHz NTSC color signal. The TIA then divides it by three, sending 1.193MHz out to the CPU. From the first video I was expecting 3.58MHz, but it's actually 1.193MHz on pin 27. This is the reading I get as well. Cool beans!

3. CPU Reset pulse:

   Spoiler

   

    

4. Replace all three chips: Now this I haven't tried yet. I suspect that because I also confirmed signal patterns on Pin A12, proving the Rom was being accessed and running, I don't actually have a problem with the RIOT or CPU. Maybe it's the TIA or it could be a bad RCA cable, I know it was smashed in the center (I think it got twisted really hard). I'm waiting for another one. I did try a Yellow composite cable, but the tip is a bit long on for the female plug on the motherboard. It went in, but didn't bottom out. No signal, same symptom. Either that's not it, or the composite cable didn't work. The Atari has a heartbeat, I'm just not getting video out. Frustrating! If I had another TIA, I'd try that. But I'll have to wait until the new Atari comes in to test.

[stigzler]

@RIP-Felix: Gonna start calling you Ben Heck. 

@ClassicGMR: Errr..Ben Heck made one of his  creations for you? o.O

[RIP-Felix]

24 minutes ago, stigzler said:

@RIP-Felix: Gonna start calling you Ben Heck. 

@ClassicGMR: Errr..Ben Heck made one of his  creations for you? o.O

How about Fix-it-Felix if and when I manage to get this problem sorted? @ClassicGMR I was wondering the same?

[stigzler]

Oh. No doubt you'll do it. Dodgy RF box? (As the vicar said to the milkmaid)

[RIP-Felix]

1 minute ago, stigzler said:

Oh. No doubt you'll do it. Dodgy RF box? (As the vicar said to the milkmaid)

That tech said it almost never goes out, so I've been focusing on all the components up to it. If after I replace the chips, and try another RCA cable, with working ones and It still doesn't work, then I may have to crack it open. It's soldered on in such a way you can't open it without desoldering it from the motherboard.

I'm at my wits end with this (literally). I can't find/think of anything else to try if swapping the chips doesn't work. If it does, then I should be able to pick up a replacement fairly cheap. I just need to know which one is bad, if any. Like you said, however, maybe it is the RF box. If that's the case, then this CX2600A is a prime candidate for a composite video mod, maybe even an RGB mod! I could always just call it dead and mod the case, but I'M GIVEN HER ALL SHES GOT CAPTAIN! If she's got nothing left to give, then I'll call it and start getting excited for the mod. In the mean time, I'll give the old girl the best care I can muster. 

PS:

It's sad when your Atari 2600 has better healthcare than you do!

[ClassicGMR]

On 8/17/2017 at 6:23 PM, stigzler said:

@RIP-Felix: Gonna start calling you Ben Heck. 

@ClassicGMR: Errr..Ben Heck made one of his  creations for you? o.O

 

On 8/17/2017 at 6:49 PM, RIP-Felix said:

How about Fix-it-Felix if and when I manage to get this problem sorted? @ClassicGMR I was wondering the same?

We're talking 14 years ago here. I did own one of the Rev 5 series he made though yes. I got out of collecting for a while and sold it off. It was an awesome little piece of kit at the time. Had a built-in paddle as well at the D-Pad. The cart plugged in at the top and made a natural sun shade. Sounded great and ran off a rechargeable camera battery.

I do miss that thing. I also miss PhillyClassic. =P

 

AWESOME EDIT!: OOH OOH! I found a page that has PhillyClassic 2001 pictures! About 2/3 of the way down the page you'll see a picture of the VCSp Rev 3(blue handheld with Jr. Pac-Man in it). The geek wearing the black Atari shirt and 80's glasses behind the TV and in the next picture is me.

[RIP-Felix]

4 hours ago, ClassicGMR said:

AWESOME EDIT!: OOH OOH! I found a page that has PhillyClassic 2001 pictures! About 2/3 of the way down the page you'll see a picture of the VCSp Rev 3(blue handheld with Jr. Pac-Man in it). The geek wearing the black Atari shirt and 80's glasses behind the TV and in the next picture is me.

You mean this? Looks like a hulker, but hey, if it works who cares.

[stigzler]

4 hours ago, RIP-Felix said:

You mean this? Looks like a hulker, 

That's not a nice way to talk about Classic, Felix!

Damn - 2001 - back when Ben Heck still had his soul. He looks so fed up on his show now since he's been bought out by the man. Amazing he was hacking all the way back then...

[RIP-Felix]

Problem Solved! It's always the little things!

Today my replacement atari's came in the mail. Yes plural. I got a Vader four switch in case I couldn't salvage mine and it was guaranteed to work or my money back. I later saw a sunnyvale heavy sixer on ebay (Untested) for cheap. I figured between the three at least 1 would be working and maybe I could salvage parts to get another working. The busted one I could use as an HTPC case or Raspberry Pi build. The vader four switcher even came with a complementary Coaxal to RCA adapter, how nice of them. Turns out, however, something unexpected happened when I plugged them in (After checking the voltage on the "new" power supply of course). All three are working!

     Turns out, it was that RCA adapter all along. Since I didn't have another one to use, I was chasing gremlins the whole time. Well, I was starting to suspect this. I knew from the electronics tests I performed that the game was running and should be sending video out if there was nothing wrong with the TIA chip (Which required a working replacement to test) or RCA cable (Which I fixed). So now I have 3 working Atari 2600s. I really like the Sunnyvale Heavy Sixer. It's in real good shape! After a little cleanup and dielectric grease, it will be my flagship 2600 (Display console). The wood-grain four switcher I will swap innards with the Vader black, because my originals player 1 difficulty switch broke off in the A position and I want the wood-grains to be in perfect shape. I'll probably keep both of these. I might sell the Vader, it's a good everyday use model, the one you let kids beat up on since it's not mint anyway (the case is in good shape, it's just that difficulty switch).

     Anecdotally, the console with the best picture (Least RF interference on screen) is the one I cleaned and thoroughly tested. The pixels actually look really good on my CRT. This is obviously the way this was meant to be played. Emulation is neat, but the real thing is...well...the real thing. I need to clean the other 2 now and reassemble them such that the Vader has all the flaws. The faceplate on my original is scratched. The vader's is pristine, so I'll swap those. I'm going to reseat all the chips just to make sure their connection is fresh. While I'm in there, I'll go ahead and check the voltages, using an oscilloscope to make sure the reset pulse and clock are in spec. It shouldn't take more than five minuets now that I know what I'm doing. These are indeed built like tanks! It's been a pleasure working on them. Its fun to learn the electronics and get them working again, even if there was nothing wrong with them in the first place...lol.

[ClassicGMR]

On 8/15/2017 at 10:48 PM, ClassicGMR said:

Also - these are AWESOME. Switchboxes can easily be bypassed now. Just FYI.

https://www.ebay.com/p/Atari-2600-RF-TV-Coaxial-F-Plug-Female-Adapter-Third-Party/691164204

*cough* *cough*

Seriously though - Glad you got it figured out and, hey.... we all learned a few things along the way! This was a great ride.

Sixers (whether Sunnyvale or light) are always preferred in my opinion. Seeing all the switches standing tall ready for use is just awesome. Also, try using a Space Shuttle overlay on a 4-switch - it sucks.

Or - even worse - playing your Atari games on an *GASP* Intellivision!!!

P.S. - Peter Cullen was the Morgan Freeman of the 80's wasn't he? His voice was everywhere!