9 replies to this topic

[ApolloBoy]

I seem to be having this weird issue with my 7800 where a couple of games (Food Fight and Pole Position II) crash in the middle of the game. Both of these games have been cleaned and they work fine on my brother's 7800, so that isn't really an issue. I'm aware that certain 7800s have this issue, and I'd like to know what I can do to fix this.

[HammR25]

Does your brother have a copy of either of those games you can test?

[ApolloBoy]

HammR25, on Sat Nov 13, 2010 8:24 PM, said:

Does your brother have a copy of either of those games you can test?

He doesn't, but I'm not sure if that would be the issue considering my copies worked perfectly fine on his 7800. I know this is a known issue with certain 7800s, I just didn't think mine would be one of them.

[gdement]

Just a shot in the dark, but I wonder if replacing the capacitors would do any good. The 2200uF cap is on the 9-10v input from the PSU, and the 220uF caps stabilize the 5v output all the chips run from.
I've had a bad cap in 2 out of 3 7800's, though 1 of them was not visibly obvious, it tested open after I removed it.

[ApolloBoy]

Thought I'd bump this since I managed to replace at least a couple of caps when I modded my 7800 last week. I replaced the 2200uF cap near the power supply jack and the 220uF cap in the center of the motherboard. Food Fight still crashes and I'm pretty sure PP II will still crash even though I haven't tested it yet. Would replacing the remaining original cap help or is there something else afoot?

[AtariLeaf]

ApolloBoy, on Sun Aug 14, 2011 1:09 PM, said:

Thought I'd bump this since I managed to replace at least a couple of caps when I modded my 7800 last week. I replaced the 2200uF cap near the power supply jack and the 220uF cap in the center of the motherboard. Food Fight still crashes and I'm pretty sure PP II will still crash even though I haven't tested it yet. Would replacing the remaining original cap help or is there something else afoot?

I don't know about PP II but Food Fight is known to crash on certain revisions of the 7800 board. See the 7800 FAQ

[ApolloBoy]

AtariLeaf, on Sun Aug 14, 2011 4:28 PM, said:

ApolloBoy, on Sun Aug 14, 2011 1:09 PM, said:

Thought I'd bump this since I managed to replace at least a couple of caps when I modded my 7800 last week. I replaced the 2200uF cap near the power supply jack and the 220uF cap in the center of the motherboard. Food Fight still crashes and I'm pretty sure PP II will still crash even though I haven't tested it yet. Would replacing the remaining original cap help or is there something else afoot?

I don't know about PP II but Food Fight is known to crash on certain revisions of the 7800 board. See the 7800 FAQ

I seem to have a bizarre system then as Decathlon and Food Fight don't work but Robot Tank does. PP II is working fine for some reason though.

Edited by ApolloBoy, Sun Aug 14, 2011 8:16 PM.

[AtariLeaf]

ApolloBoy, on Sun Aug 14, 2011 8:15 PM, said:

AtariLeaf, on Sun Aug 14, 2011 4:28 PM, said:

ApolloBoy, on Sun Aug 14, 2011 1:09 PM, said:

Thought I'd bump this since I managed to replace at least a couple of caps when I modded my 7800 last week. I replaced the 2200uF cap near the power supply jack and the 220uF cap in the center of the motherboard. Food Fight still crashes and I'm pretty sure PP II will still crash even though I haven't tested it yet. Would replacing the remaining original cap help or is there something else afoot?

I don't know about PP II but Food Fight is known to crash on certain revisions of the 7800 board. See the 7800 FAQ

I seem to have a bizarre system then as Decathlon and Food Fight don't work but Robot Tank does. PP II is working fine for some reason though.

From a cursory look at the FAQ, you may have deck 3 which is - 3 A1 77 5951337 Taiwan Hole/no pins 002 REV A 87-17

It lists Food Fight as locking and Decathalon a no go at all.

[ApolloBoy]

AtariLeaf, on Mon Aug 15, 2011 11:58 AM, said:

ApolloBoy, on Sun Aug 14, 2011 8:15 PM, said:

AtariLeaf, on Sun Aug 14, 2011 4:28 PM, said:

ApolloBoy, on Sun Aug 14, 2011 1:09 PM, said:

Thought I'd bump this since I managed to replace at least a couple of caps when I modded my 7800 last week. I replaced the 2200uF cap near the power supply jack and the 220uF cap in the center of the motherboard. Food Fight still crashes and I'm pretty sure PP II will still crash even though I haven't tested it yet. Would replacing the remaining original cap help or is there something else afoot?

I don't know about PP II but Food Fight is known to crash on certain revisions of the 7800 board. See the 7800 FAQ

I seem to have a bizarre system then as Decathlon and Food Fight don't work but Robot Tank does. PP II is working fine for some reason though.

From a cursory look at the FAQ, you may have deck 3 which is - 3 A1 77 5951337 Taiwan Hole/no pins 002 REV A 87-17

It lists Food Fight as locking and Decathalon a no go at all.

I have a Chinese-made 7800 that was manufactured around mid-1990, so it doesn't correspond with the list. Also, console 3 on the list doesn't work with Robot Tank but mine does.

[gdement]

ApolloBoy, on Sun Aug 14, 2011 1:09 PM, said:

Thought I'd bump this since I managed to replace at least a couple of caps when I modded my 7800 last week. I replaced the 2200uF cap near the power supply jack and the 220uF cap in the center of the motherboard. Food Fight still crashes and I'm pretty sure PP II will still crash even though I haven't tested it yet. Would replacing the remaining original cap help or is there something else afoot?

If the remaining 220uF happens to be open then it might help, but at this point it looks increasingly unlikely that this is the problem. The 220uF caps are in parallel so they can cover for each other to some extent.
Most likely something else is wrong.