Atari Tetris PCB cap kit listing / audio repair

[ieure]

My Tetris was making an awful buzzing sound over all the music & sfx. I figured it was caps in the audio section of the board, but didn't see anyone else with issues, cap kits, or cap listings. Unfortunately, there's no schematic or parts list for this board to pull the cap list from. Here's the parts list I came up with from examining the board:

C13 47uf 10v
C54 2.2uf 50v
C58 2.2uf 50v
C60 1000uf 25v
C61 10uf 35v
C62 220uf 10v
C63 2.2uf 50v
C64 47uf 10v
C65 47uf 10v
C66 100uf 10v
C67 100uf 10v
C68 100uf 10v

You'll want to get the smallest cases possible on those caps, since the parts are very close together. You could skip C13 & C54, which aren't part of the audio section, but I opted to replace them all, as it was only around three bucks from Mouser for everything.

I replaced all the caps and powered up — it still had the buzz. It's always really disappointing when this happens. I decided to hit the start button, and was nearly blown through the wall by how loud it was! I adjusted the volume to a more reasonable level, and the buzzing is cured. I guess the only way to get any audio at all through the tired old caps was to crank the volume near max, which made for terrible SnR. I'm very happy to have this issue solved.

 

[thegleek]

Very very cool man! I have one of these pcb's and this will indeed come in handy down the line when I re-cap the entire board! yay thx!

 

[JoshODBrown]

Thanks, I'll be doing this same cap replacement on my Tetris shortly. One thing i will add to this thread (once i dig out my caliper) is the diameter measurement for the original caps, since they are pretty tight together on the board and ordering one cap thats just a little too big will potentially throw off the repair job.

 

[JoshODBrown]

In case this is helpful for someone else, I measured the original cap diameters on my Atari Tetris. They really are quite tight together and you're not going to want to go much bigger than what i have listed

C60 1000uf 25v - 13.5mm
C62 220uf 10v - 7mm

Everything else below is about 5.25mm

C13 47uf 10v
C54 2.2uf 50v -
C58 2.2uf 50v
C61 10uf 35v
C63 2.2uf 50v
C64 47uf 10v
C65 47uf 10v
C66 100uf 10v
C67 100uf 10v
C68 100uf 10v

 

[ArcadeDanger]

This is great Ieure! Your story was similar to mine with Missile Command, one of the amps was going and when I replaced it the buzz was still there, when I went to play the huge warning klaxon sound scared the lights outta me.

I dunno if you mapped the actual audio section as separate from the rest; I've got a Tetris PCB that's playing blind, replaced some ICs in the path, but haven't been able to figure it out. I got a working one now, someday I'll sit down and compare them both.

 

[ChanceKJ]

Thanks, I'll be doing this same cap replacement on my Tetris shortly. One thing i will add to this thread (once i dig out my caliper) is the diameter measurement for the original caps, since they are pretty tight together on the board and ordering one cap thats just a little too big will potentially throw off the repair job.

https://youtu.be/Wv2QHW0zW6c

 

[CossackWarrior]

https://youtu.be/Wv2QHW0zW6c

Nice videos, I had no clue you guys made vids. Cool. More awesome stuff to watch. Keep em coming.

 

[ArcadeDanger]

Does anyone know what function/section the other two capacitors serve?

 

[JoshODBrown]

Does anyone know what function/section the other two capacitors serve?

I'd be interested in finding the schematics for this board.

 

[ArcadeDanger]

General consensus is that the schematics don't exist...

 

[jarcade]

General consensus is that the schematics don't exist...

That's pretty odd for Atari. I thought they were really good about including schematics and parts lists for most of their games.

 

[ieure]

That's pretty odd for Atari. I thought they were really good about including schematics and parts lists for most of their games.

Pretty much anything made post-1982 has schematics that range from unreadable to non-existent.

 

[JoshODBrown]

So i capped my Atari Tetris audio section tonight and the good news is I didn't blow anything up. the bad news is my volume is pretty much exactly the same as it was when i started. I'm pretty sure the volume pot is ok, but its hard to know without knowing what its specs are supposed to be.

Does anybody happen to have any insight on what i should check next? this is a real son of a bitch to diagnose without a working Tetris to compare to. Ive already tried the board in two different cabinets with known working speakers, and my volume is probably a 2 out of 10 with the volume dialed up all the way on the board.

next suspect might be the LM324, but im not entirely sure what i need to test for there yet with the various pins. 12 volts bang on when i test pins 11 and 4 on the LM324.

Edit: had a chance to Test the pot, seems it should be 1K ohm and was ok. Also, had a theory a pokey could be bad, swapped them out and no change. So I'll probably look at the resistors involved in the audio section, along with whatever i can do to test the LM324. If anybody has pointers for testing that, let me know. The only tools i have available at the moment are a multi meter and a logic probe.

 

[ieure]

So i capped my Atari Tetris audio section tonight and the good news is I didn't blow anything up. the bad news is my volume is pretty much exactly the same as it was when i started. I'm pretty sure the volume pot is ok, but its hard to know without knowing what its specs are supposed to be.

Does anybody happen to have any insight on what i should check next? this is a real son of a bitch to diagnose without a working Tetris to compare to. Ive already tried the board in two different cabinets with known working speakers, and my volume is probably a 2 out of 10 with the volume dialed up all the way on the board.

next suspect might be the LM324, but im not entirely sure what i need to test for there yet with the various pins. 12 volts bang on when i test pins 11 and 4 on the LM324.

Edit: had a chance to Test the pot, seems it should be 1K ohm and was ok. Also, had a theory a pokey could be bad, swapped them out and no change. So I'll probably look at the resistors involved in the audio section, along with whatever i can do to test the LM324. If anybody has pointers for testing that, let me know. The only tools i have available at the moment are a multi meter and a logic probe.

LM324s are extremely failure-prone. I wouldn't bother to test, just socket and replace it.

 

[ArcadeDanger]

Hey just wanted to add to this very helpful thread. There are variations of the audio section components for these boards. My two Tetris boards have 7 and 8 capacitors as opposed to the 12 listed by JoshODBrown and Ieure (and their audio does work, looking at this cause they do sound weak/cut out/out of spec).

Tetris PCB Board revision 007
*C60 1000uf 25v - 13.5mm
About 5.25mm or less:
*C13 47uf 10v
*C54 2.2uf 50v
*C58 2.2uf 50v
Close Proximity
*C63 2.2uf 50v
*C64 47uf 10v
*C65 47uf 10v


Tetris PCB Board revision 004
*C60 1000uf 25v - 13.5mm
About 5.25mm or less:
*C13 47uf 10v
*C54 2.2uf 50v
*C58 2.2uf 50v
Close Proximity
*C63 2.2uf 50v
*C64 47uf 10v
*C65 47uf 10v
**C66 100uf 10v

 

[ieure]

Wow, thanks for the additional info! I dug out my extra to compare to the one I made that listing from, and it looks like it has the same 7 caps as your first board.

There's a sticker on the PCB I used for my initial listing which reads

TETPCB01 TETRIS
A046905-01

Presumably this is the first revision of the PCB.

The other one I have doesn't have a sticker, but "006" is written in permanent marker just to the right of the copyright. It's hard to make yours out, but it looks like you might have -004 and -007 PCB revisions — can you check and confirm? It would be good to identify the different lists by the board revision.

 

[ieure]

Oh, also, the volume pot is mounted backwards on my -01 PCB. It faces in towards the center of the PCB, while the pot on the 006 revision faces out towards the JAMMA edge. Production error?

 

[ArcadeDanger]

The other one I have doesn't have a sticker, but "006" is written in permanent marker just to the right of the copyright. It's hard to make yours out, but it looks like you might have -004 and -007 PCB revisions — can you check and confirm? It would be good to identify the different lists by the board revision.

Good call out, updated the original thread with the rev numbers, 004 and 007. I checked EPROM against mame on 004, seems like same code. Wonder if the programs changed or just the Capacititors?

 

[sparksterz]

I'll have to check and look at my board, I knew it was missing some of the caps in the first post. I'm having pretty nasty audio issues with mine, but I haven't figured whether it's an issue with the board or how my cabinet is wired yet :/