No Sound on My Sega New Astro City

[slapaham]

Well, I'm making progress on this cab now. Concluded the monitor is dead but this shouldn't be a problem as I have at least one spare monitor I can replace it with. However, I'd like to get the sound sorted so that I can at least conclude that everything else is okay.

I've carried out lots of multimeter tests - PSU , 5, 12. etc and they were all okay. In reference to the photo I have taken below... I have connected the speakers to the Sound Out and they are humming, so clearly the amp and speakers are working, however, what do I connect to the Sound In socket, if anything? It seems logical to me that would be the sound from the board but I can't find any type of cable to connect into the socket - please could someone help!

Also, if someone could also help me with telling me what each of these sockets are (pictured below), that would also help me... So far I have concluded (going from left to right)

1. Something to do with speakers?!
2. Player 1 controls?
3. Player 2 controls?
4. Credit counter!?
5. Ground



Sorry for being a total 'noob' (hate that term!) but if anyone could help a king one, then I'd be really grateful!

[Kevin Mullins]

See if this helps:
http://bonbaiserdecapo.free.fr/temp/doc%20astro.pdf

There are schematics and a wire color code chart on the last few pages.

[slapaham]

Thanks Kevin.

I always find the wiring diagrams a mess to follow. I followed the speaker wires from my Jamma harness but the inside of an Astro is a nightmare!!

I'll take a long, hard look at the diagram and hopefully figure it out.

 

[slapaham]

Right, I've made progress on this - I have sound! But it is soooooooo quiet, you have to have your ear shoved right against the speaker to hear anything! What can I do to sort this problem out?

Thanks guys!

[Malenko]

amp, volume pot, sound setting on board?

what game are you running, and is there a volume control menu/pot for it?  for example, NBA Jam requires an external pot, MKII has volume control in the operator menu and Tekken 2 has a pot built into the board.

[slapaham]

Hi chap

Well, as far as I'm aware, you don't actually need to use the sound amp on Jamma PCBs. I think the amp is there for other formats such as STV, etc which require an external amp (although I could be wrong on this!)

Anyway, sound kicked in completely randomly so I'm assuming there may be a loose connection somewhere - I'm hoping nothing too serious!

Thanks for the feedback, appreciate it!

[HaRuMaN]

Anyway, sound kicked in completely randomly so I'm assuming there may be a loose connection somewhere - I'm hoping nothing too serious!

The culprit for this is usually the pot.

[slapaham]

Are they easy enough to replace/sort? Also, is it a pricey procedure?

Cheers for the help

[Zebidee]

Fiddle with the volume pot before you go and replace it - if the sound is scratchy and comes/goes suddenly as you adjust the pot, then replace it. They are very cheap & easy to replace.

[slapaham]

Ah, that's reassuring, cheers Zebidee!