Sega Naomi Uni Sound Amp problem

Flazh · Post by **Flazh** » October 6th, 2008, 2:12 am

I just moved my Uni upstairs, and without thinking too much obviously, instead of plugging the white left hand audio line into the left hand speaker, I did the clever thing and plugged it into the 12v line coming off the JVS I/O. Now even with it all plugged in correctly I'm getting a massive buzzing sound on both speakers.

Any idea what has blown on the amp and if it's fixable, or am I in the market for a new amp?

Post by **grantspain** » October 6th, 2008, 11:50 am

without looking at the schems i would say you have shorted the +12 so trace the +12 back until you find it again-my guess is that you have fried the amp ic but also you may have just killed the 12v reg

Flazh · Post by **Flazh** » October 6th, 2008, 1:38 pm

Everything else is working fine though, it is just the amp that isn't working properly. It is actually still giving out audio, but with huge distortions, which is making me think I've killed a cap or something instead of completely frying the amp.

Post by **markedkiller78** » October 6th, 2008, 5:02 pm

Sorry to intrude, but I'm hopign that the same advice wil help us both

I've got a weird problem with my amp / speakers. In stereo, wired with phone jacks, the sound is perfect, but over mono via the jamma connector it has a horrible buzzing.

Any ideas what it could be? I've half herted looked for a broken connection from the jamma harness, but to no avail.

Flazh · Post by **Flazh** » October 6th, 2008, 5:42 pm

I'm guessing that it will be blown caps that have done it. That's what I think will have happened to mine. Hopefully someone will be able to confirm/deny that possiblility though.

Post by **cools** » October 6th, 2008, 5:44 pm

markedkiller78 wrote:Sorry to intrude, but I'm hopign that the same advice wil help us both

I've got a weird problem with my amp / speakers. In stereo, wired with phone jacks, the sound is perfect, but over mono via the jamma connector it has a horrible buzzing.

Any ideas what it could be? I've half herted looked for a broken connection from the jamma harness, but to no avail.

It's not mains hum is it? I used to get that with my old woodie MAME setup, until I sorted out the grounding.

Post by **grantspain** » October 6th, 2008, 5:50 pm

Flazh wrote:Everything else is working fine though, it is just the amp that isn't working properly. It is actually still giving out audio, but with huge distortions, which is making me think I've killed a cap or something instead of completely frying the amp.

i am talking about the voltage on the sound amp itself and the amp ic

Flazh · Post by **Flazh** » October 6th, 2008, 5:51 pm

Ah ok. So that would definitely put me in the market for a new amp then

Post by **markedkiller78** » October 7th, 2008, 9:20 am

cools wrote:
markedkiller78 wrote:Sorry to intrude, but I'm hopign that the same advice wil help us both

I've got a weird problem with my amp / speakers. In stereo, wired with phone jacks, the sound is perfect, but over mono via the jamma connector it has a horrible buzzing.

Any ideas what it could be? I've half herted looked for a broken connection from the jamma harness, but to no avail.
It's not mains hum is it? I used to get that with my old woodie MAME setup, until I sorted out the grounding.

Could be mate. It's perfect in stereo, but that comes from a different lead.

How do I check if the jamma harness is grounded properly?

Sega Naomi Uni Sound Amp problem

Sega Naomi Uni Sound Amp problem

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