2600A troubleshooting help with timing/raster?

[ATekGuy]

I have scoured the forum for something similar to what I am seeing with my 2600A, but not seeing anything. Would someone know what may be causing these symptoms?

 

1) Pole Position starts fine, music plays well, but once the game starts, the 90-second clock counts down in about 2 seconds

2) Many other games come up (not all), but the TV image is jumbled or rasters bad

3) Paul Slocum's Testcart will not even start

 

If there are other tests I can do to help narrow it down, I will gladly try them. I do have meters and an oscilloscope, just limited knowledge of the circuitry.

 

[ATekGuy]

Anyone?

[Thomas Jentzsch]

I suppose the TIA or RIOT are internally broken. Also a weak power supply can lead to all kinds of effects.

 

Do any games work fine?

[ATekGuy]

I was hoping it might be the power, but got ahold of a new supply, and no help. I'm starting to suspect the TIA as well.

 

None of the carts I have play properly. Most are just black screen. 

 

Pole Position looks normal and almost plays, but there's that weird timing. 

 

Centipede starts normal and is almost playable, except the joystick moves the block too fast, it looks like it is everywhere at once. And the centipede is broken.

 

Asteroids boots to the copyright, but it displays wrong, broken similar to the centipede, and won't go any further.

 

I do want to mention I have the chance to check the carts, they all play good on another 2600.

 

Please forgive the snow. I hooked it up quick to get the pictures, and the RF switch I grabbed must be dirty.

[zylon]

looks like RIOT memory errors

[ATekGuy]

32 minutes ago, zylon said:

looks like RIOT memory errors

Oops, yeah, that makes more sense. I was caught up in the timing issue. I may try to get a couple chips and see about swapping them out. Can't make it more broken than it is, right? 😂