NES Repro - Getting sound but no picture

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ramiq27
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NES Repro - Getting sound but no picture

Post by ramiq27 » Sun Oct 16, 2016 4:43 am

I'm fairly new to NES Repros. I've done 15-20 repros in the past without any issues.

Lately however the last three tries have ended in failure.

My latest is giving me sound but no picture. The one before it gave me scrambled graphics. And the first try ended up with no image or sound.

Here's some info:

I am using m27c2001 EPROMS on TLROM boards.

Any idea what the problem is?

Any help is appreciated.

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rainwarrior
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Re: NES Repro - Getting sound but no picture

Post by rainwarrior » Sun Oct 16, 2016 9:37 am

If you get sound and can verify by that the game is running correctly, then you've probably got the PRG wired correctly, and the lack of picture may be due to faulty CHR wiring, so perhaps focus your attention there.

If you have sound but it doesn't sound like the game is fully operational (despite the lack of picture) then PRG could be a problem still as well.

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getafixx
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Re: NES Repro - Getting sound but no picture

Post by getafixx » Sun Oct 16, 2016 12:25 pm

Are all three boards using the same game? Could be a bad ROM dump, or a bad patch.

ramiq27
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Re: NES Repro - Getting sound but no picture

Post by ramiq27 » Sun Oct 16, 2016 12:51 pm

rainwarrior wrote:If you get sound and can verify by that the game is running correctly, then you've probably got the PRG wired correctly, and the lack of picture may be due to faulty CHR wiring, so perhaps focus your attention there.

If you have sound but it doesn't sound like the game is fully operational (despite the lack of picture) then PRG could be a problem still as well.
I have checked and rechecked my wiring and cannot find any faults in both PRG and CHR. I will have another look.
getafixx wrote:Are all three boards using the same game? Could be a bad ROM dump, or a bad patch.
I have used the same files multiple times before and had no issues.

I am starting to suspect my programmer now. I am using TOP3000. Burning the EPROMs completes and verifies without any issues however.

lidnariq
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Re: NES Repro - Getting sound but no picture

Post by lidnariq » Sun Oct 16, 2016 1:46 pm

On the off-chance that this is the problem...
UVEPROMs get slower after every erase cycle, but they'll still validate in a programmer.

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