Repairing my VCS, help needed.

[vitoco]

Hi!

 

When I turn my 2600 on, it starts and looks good. After a couple of minutes, some waves appear in the screen, which look like this:

 

 

What could be happening?

 

Background: during mid 1984 there was a flood in my neightborhood, and this VCS was recovered from the mud along many other electronic devices. I was told that they were just cleaned with water an then stored for about a year. I forgot it because I had just started using my 800XL, with both the joysticks and paddles from the 2600. I kept the 2600 with me, but I never tried to turn it on again until few years ago during a local retro meetup, where I discovered this problem. I stored it again until this week, and I opened the case to see how bad it could be.

 

It is a 2600A rev 13 board (C015519) from 1980, and the top of the board does not look too bad, but there are some "bubbles" under the traces in the bottom.

 

Any help, tip or suggestion is welcome.

 

Time for an A/V mod?

 

[Al_Nafuur]

Maybe dirt or corrosion in the RF module? Can you send some pictures of the board.

 

[vitoco]

2 hours ago, Al_Nafuur said:

Maybe dirt or corrosion in the RF module? Can you send some pictures of the board.

I took some pictures, but there wasn't enough light to get clear ones. I'll try again tomorrow in the morning.

 

BTW, I opened the metallic shield and found socketed ICs. I don't know if this is good or bad, as it seems that at least one pin of the TIA appears to have rust.

 

Thanks!!!

 

++V

 

[vitoco]

Here are some hi-res pictures I took this morning:

 

 

 

 

 

Thanks!

 

[Al_Nafuur]

Most problems in electronics are contact problems, and the pins of your ICs look like they could serve as an example in the electronics textbook. I recommend removing and cleaning them carefully and the sockets too.

[vitoco]

When I removed the ICs, I found a bit of dry mud under 2 of them! 😱

 

I cleaned the board and ICs with some baking soda, vinegar and a tooth brush. I removed the visible rust and all the dust. I let it dry the whole day after a final wash.

 

I did a test, and this time the waves appeared after 7 minutes, more than the double of the last time. As I connected it without its shield and unmounted, I could test if any of the ICs was hotter than usual (for an 800XL), but I found none.

 

Any other idea?

 

BTW, during a retro meeting some years ago, some people brought old pieces of hardware to exchange or give away, and I picked a 2600 clone. I was said that it was bad, but I thought that I could use some parts of it to repair my 2600, and also take the 32 built in ROM. I store it with my 2600 until now. I also opened it to examine it and I found that the board was even smaller than the 2600A, and it said 2600B-5232. It seems that someone opened it and stepped on it. I found that there was a shortcut between a resistor and a bent concenser, so I lift it and all the remaining bent components. I powered it on and it started. Instead of a TV type (color or B/W) switch, there is another trigger switch that changes between the games in its ROM, and I could see the whole collection. The only problem was the audio, because it was a bit noisy or scratchy. Obviously there were no reusable components inside it, and I'm not sure which kind of IC components are them.

 

[cvga]

This sounds like a job for @Cmherndon79

 

He's fixed over 250 ataris in the past year or so including mine.

[Yarzzz]

My Super nintendo had a similar problem of wavy lines that got corrected by changing the 7805 voltage regulator. Ive also read that faulty capacitors can cause this kind of issues. 

[+Mockduck]

Just on the off chance that this isn't a hardware issue, try plugging the atari into a different circuit in the home, or maybe see if something like a fridge might be kicking in and causing RF interference. 

[Al_Nafuur]

17 hours ago, vitoco said:

When I removed the ICs, I found a bit of dry mud under 2 of them! 😱

 

I cleaned the board and ICs with some baking soda, vinegar and a tooth brush. I removed the visible rust and all the dust. I let it dry the whole day after a final wash.

Did you opened the RF module and cleaned it too? I never did this, so I can't tell you how and what to look for.

[vitoco]

44 minutes ago, Mockduck said:

Just on the off chance that this isn't a hardware issue, try plugging the atari into a different circuit in the home, or maybe see if something like a fridge might be kicking in and causing RF interference.

I don't think so, because it is already in a different circuit. And the same happened at another place. It looks like something that it is getting too hot or something like that, because the problems start after some mintutes of operation. But there is another thing that it is external: the power suply. It is not the original one, I bougth my VCS in the U.S. and I had to use an 220V universal adaptor. I don't have another one to try... might it be the power supply for the 1050 disk drive?

 

2 hours ago, Yarzzz said:

My Super nintendo had a similar problem of wavy lines that got corrected by changing the 7805 voltage regulator. Ive also read that faulty capacitors can cause this kind of issues.

I have no idea on how to test ceramic capacitors. That also goes to the voltage regulator (78M05C in this case). I'll have to investigate that.

 

35 minutes ago, Al_Nafuur said:

Did you opened the RF module and cleaned it too? I never did this, so I can't tell you how and what to look for.

I couldn't open the RF module because the cap is soldered to the miniboard it contains, which is soldered to the 2600 board.

 

What it is strange is that I turn it on and need to wait some minutes to get the waves, and if I turn it off and immediately on, I have to wait again for the waves, they do not appears immediately.

 

Another problem I can see is that there are a lot of other static vertical bars or spots depending on the background's color. I'm not sure if this is because I'm running unshielded.

 

 

[djsky717]

Vitoco, Does the problem temporarily goes away when you turn if off for a few minutes and then turn it back on? If so, you most likely have a bad C241 and/or bad C242, both of which are 0.1 uF (or sometimes they are 0.22 uF) capacitors. I would replace both using the 0.22 uF values as your next step. Hope this helps!

[vitoco]

16 minutes ago, djsky717 said:

Vitoco, Does the problem temporarily goes away when you turn if off for a few minutes and then turn it back on? If so, you most likely have a bad C241 and/or bad C242, both of which are 0.1 uF (or sometimes they are 0.22 uF) capacitors. I would replace both using the 0.22 uF values as your next step. Hope this helps!

It temporarily goes away even if I turn it off and on again in less than a second.

 

Looking at my board, I found these:

• C241 is 0.1K 100VY (multilayer polyester film besides the voltage regulator)
• C242 is 0.1Z Z5T 16V (ceramic disc besides the power connector)

I'll try to replace both, but the field service manual sais: "Make certain the replacement components are rated at a value 50V or greater." for this issue. I hope I could find them in the local market for speed.

 

Thank you for the tip!!!

 

[ChildOfCv]

On 9/30/2020 at 1:18 PM, vitoco said:

I have no idea on how to test ceramic capacitors. That also goes to the voltage regulator (78M05C in this case). I'll have to investigate that.

It's typically not the ceramic caps that cause problems, but the large electrolytics.  If there's bulging or staining on the board around them (staining may not be apparent anymore if you washed it), the cap is bad.

 

To test the regulator, make sure the components get +5V on the power rails in DC mode, and close to 0V in AC mode.

[Cmherndon79]

Just saw that @cvga tagged me, sorry I didn't respond sooner 🙂.  @vitoco my money is on the power adapter. I've seen that behavior on a number of power adapters.  The 2600 is very sensitive to noise from the power adapter or on the same circuit. For a long time when I was starting out doing refurbs on these consoles, I'd source new/old power adapters from a local thrift store and convert them over to the Atari plug and for some power adapters I'd see behavior like what you're seeing.  These days I keep an eye out for lots of higher quality Taiwanese designed power adapters on eBay like ones from Lite-On or Bestec and convert those.  I know if a few quality aftermarket 110v adapters and Best Electronics sells new-old stock 110v Atari ones.  Don't have any experience with 220v unfortunately.

 

Also, yeah I always change out the caps at C241/242 on the 4 switch boards with .22uF 100v caps. I've never seen that wavy behavior though. The lowe rated caps originally installed cause "snow or sparkles" in the picture. 

 

Also, you can improve the color saturation on the rev13 board by installing a 820 ohm resistor between pins 6 and 9 on the TIA chip.

[vitoco]

6 hours ago, Cmherndon79 said:

my money is on the power adapter. I've seen that behavior on a number of power adapters.  The 2600 is very sensitive to noise from the power adapter or on the same circuit. For a long time when I was starting out doing refurbs on these consoles, I'd source new/old power adapters from a local thrift store and convert them over to the Atari plug and for some power adapters I'd see behavior like what you're seeing.  These days I keep an eye out for lots of higher quality Taiwanese designed power adapters on eBay like ones from Lite-On or Bestec and convert those.  I know if a few quality aftermarket 110v adapters and Best Electronics sells new-old stock 110v Atari ones.  Don't have any experience with 220v unfortunately.

I have lots of power adapters from many devices and components, from 2.7V up to 15V and the only one near 9V is the one I use with my 1050 disk drive, but I forgot it's 9.5V AC, not 9V DC as the original one (AFAIK). I'll try to find another in local stores. Also, I'll try to connect the current adapter to a different circuit than the TV set.

 

7 hours ago, Cmherndon79 said:

Also, yeah I always change out the caps at C241/242 on the 4 switch boards with .22uF 100v caps. I've never seen that wavy behavior though. The lowe rated caps originally installed cause "snow or sparkles" in the picture. 

I guess that it could solve this other behavior I noticed after I did the maintainance of my board:

 

 

9 hours ago, Cmherndon79 said:

Also, you can improve the color saturation on the rev13 board by installing a 820 ohm resistor between pins 6 and 9 on the TIA chip.

I'll also try that.

 

BTW, do you recommend an A/V mod on this board?

 

Thank you so much!!!

 

[vitoco]

22 hours ago, ChildOfCv said:

To test the regulator, make sure the components get +5V on the power rails in DC mode, and close to 0V in AC mode.

With the board powered using the power adapter, I read 4.88V and 0V respectively.

 

[Cmherndon79]

@vitoco, np  

 

Oof, yeah if that is AC, you should certainly be using a DC adapter. 

 

Yeah, changing out those caps from .1uF to .22uf will clean up the signal.  But, if you're using RF without the aluminum shielding installed, you'll also see a lot of interference and it looks like that could be the case from the picture, just based on what I've seen.  I almost always mod these for Composite and line out audio and remove the RF modulator and in those cases you don't need the RF shielding.  Mainly, I sell reworked and modded consoles on eBay and even with Composite video some newer LCDs have trouble with the 2600's output signal or don't have composite video at all and certainly not an analog NTSC tuner available.  I do have people that have requested that I not mod, but just replace electrolytic caps, those caps at C241/C242, audio caps new voltage regulator and power jack and I've found that if I run the console without the shielding in tact for testing I get a lot of extra noise on the screen from the board causing interference. 

 

Modding for AV is a personal choice.  RF isn't awful, especially considering the resolution of the 2600.  You gain a bit of additional sharpness moving to composite and the bulk of the mods that I do are just using a pair of resistors and a transistor.  There is a pinball machine guy that has custom boards made for machines in the US that also produces a PCB to install that mod on that I use, but there are a lot of others out there if you search, that will provide you with all the parts needed, in kit form.  There is also the UAV mod, which is excellent, but costs a lot more ($30 USD vs about $1), it works on all the 8 bit Atari consoles and computers and have a very excellent picture, but in my personal opinion doesn't do much for the 2600 output, compared to later consoles and the 8-bit computers.

 

My personal opinion is, yeah, I'd mod it for composite video.  The uncomplicated A/V mod is very inexpensive and if you've got a basic knowledge of soldering, not hard to perform.  In fact when I started down this road over a year ago, I knew how to solder, but I wasn't especially good, but I got it to work on my first try.  The UAV mod on the 4-switch boards requires a lot more wiring and soldering and worth it, if you are willing to spend more and run more wires to various locations.  More so, than the improved video signal from modding in my opinion is the flexibility.  We had a period this summer, where my wife's parents, her brother and sister in-law all quarantined, then went to spend time in cabins on a lake.  I brought my Atari knowing they would have a TV there, but knew it probably wouldn't work on RF.  We had so much fun playing games when the kids went to bed.  Warlords was by far everyone's favorite, since you can have 4 players. 

[vitoco]

1 hour ago, vitoco said:

With the board powered using the power adapter, I read 4.88V and 0V respectively.

I waited for the waves to appear on screen and read it again ftom the regulator: instead of 4.88V, I got variable values between 4.61V to 4.67V for some minutes... With this lectures I thought that the problem was the regulator. Some minutes later, I read between 4.56V to 4.60V, and then between 4.54V to 4.59V. At this point, from the other pin I read an input of 10.97V to 11.00V. I'm not sure on how many minutes have gone, but now it reads from 4.30V to 4.33V in the output and between 11.37V and 11.43V in the input of the regulator.

 

I disconnected the power adapter and measured it directly from the jack: 12.5V instead of ~9V. It is a Macrotel universal power adaptor from 220V AC to some DC usual values between 1.5V and 12V. I moved the selector dial to test its range and now it reads a constant 19.29V!!!!

 

Conclusion:

11 hours ago, Cmherndon79 said:

my money is on the power adapter.

You seemed to be right. I have to discard the adapter and buy a new one. Output 9V AC, 500mA(at least), (+) in center, right? 

 

1 hour ago, Cmherndon79 said:

My personal opinion is, yeah, I'd mod it for composite video.  The uncomplicated A/V mod is very inexpensive and if you've got a basic knowledge of soldering, not hard to perform.

I see 2 advantages of the mod:

- RF interference should not affect the image (I'm guessing!)

- A/V could be used with more displays. (*)

 

I've read that you have to remove the RF componente for the mod. Is that true? Could both be active at the same time?

 

(*) I connected the 2600 directly to the antenna input of my 3D LG smart TV and I couldn't pick the image. I don't know if the TV set was expecting digital signals in channels 2 or 3 instead of VHF ones for NTSC. I quit and connected it to the old CRT. BTW, I also tried with my 800XL, unsuccessfully.

 

1 hour ago, Cmherndon79 said:

Warlords was by far everyone's favorite, since you can have 4 players.

I tried my copy of Warlords (SEARS) in these tests, and I only got a black screen. I hope that solving the power issue it will work. If not, there is a case donor for my game.

 

Thank you again...

 

[ChildOfCv]

9VDC.  One of the first components is a large electrolytic cap, and reverse-biasing them is harmful.  AC voltage is reverse-biased for half of its cycle.  The other issue is that the capacitor is there to filter the input voltage to help the regulator.  The negative AC cycle discharges it, and that's not what you want.

[vitoco]

 

4 hours ago, ChildOfCv said:

9VDC.  One of the first components is a large electrolytic cap, and reverse-biasing them is harmful.  AC voltage is reverse-biased for half of its cycle.  The other issue is that the capacitor is there to filter the input voltage to help the regulator.  The negative AC cycle discharges it, and that's not what you want.

Just to be clear, I never connected an AC power source to the VCS, and I didn't fully understand what you meant with "AC mode" here:

On 10/2/2020 at 10:51 PM, ChildOfCv said:

To test the regulator, make sure the components get +5V on the power rails in DC mode, and close to 0V in AC mode.

 

[Cmherndon79]

8 hours ago, vitoco said:

 

 

I see 2 advantages of the mod:

- RF interference should not affect the image (I'm guessing!)

- A/V could be used with more displays. (*)

 

I've read that you have to remove the RF componente for the mod. Is that true? Could both be active at the same time?

 

 

 

Hey @vitoco.  Yeah, if you do a composite AV mod you won't get video interference when the RF shielding is removed.

 

As far as removing the RF modulator, there are two options when AV modding.

 

If you do the simple AV mod consisting of a pair of resistors and a transistor, yes the RF modulator needs to be removed or disabled (back when I started I'd just cut the pins and leave the modulator in place, now I remove them entirely and sell them to people looking for them for not much more than shipping cost.).  I have probably 80+ RF modulators compatible with light sixers and 4 switch boards if anyone wants one.

 

If you do the UAV mod you can leave the RF modulator in place and continue to use either.  Probably using both at the same time won't work well, just one at a time.  Also if using the UAV mod, you do not want to install or make sure that there is no 820 ohm resistor installed between pins 6 and 9 on the TIA as this, while recommend originally by Atari messes with the UAV mod.

[vitoco]

17 minutes ago, Cmherndon79 said:

If you do the simple AV mod consisting of a pair of resistors and a transistor, yes the RF modulator needs to be removed or disabled (back when I started I'd just cut the pins and leave the modulator in place, now I remove them entirely and sell them to people looking for them for not much more than shipping cost.).  I have probably 80+ RF modulators compatible with light sixers and 4 switch boards if anyone wants one.

Could you provide a link for the simple AV mod? I've already seen some pages or videos, but I'd like to follow the one that has been succesfully done 80+ times 

 

Once again, thank you!

 

[Cmherndon79]

Np 🙂.  This is the guide I used when I got started:

 

https://vintagegamingandmore.com/installation-guide-4switch/

 

It doesn't mention removing R222, R209 and C209 which I also do.  Here is a picture of a board I finished last night

[ChildOfCv]

 

8 hours ago, vitoco said:

Just to be clear, I never connected an AC power source to the VCS, and I didn't fully understand what you meant with "AC mode" here:

On 10/2/2020 at 8:51 PM, ChildOfCv said:

To test the regulator, make sure the components get +5V on the power rails in DC mode, and close to 0V in AC mode.

A voltmeter has two voltage reading types, AC and DC.  If you see symbology such as a flat line over one range and a wavy line on the same range of a different setting, the wavy line is AC and the flat line is DC.  Anyway, I'm confused about what you mean by "never connected an AC power source".  You were asking what kind of adapter to buy:

17 hours ago, vitoco said:

You seemed to be right. I have to discard the adapter and buy a new one. Output 9V AC, 500mA(at least), (+) in center, right? 

If the output is 9VAC, and you attached it to the VCS, then you attached an AC power source.  You want a 9VDC, 500mA or better adapter.