G8000 with no sound

[raycarr00]

looks clean,original and unmolested.
check components on power board...

 

[thesaint]

The black wire is attached, it is just pushed up in that direction.

Pulled and out back all connections, cleaned pins that needed it, all good.

r23 reads 475 ohms
r24 reads 472 ohms
How can that be?

 

[petehall347]

is that both channels ? .
yellow violet black ?

 

[thesaint]

Sorry, did this on F-2809

 

[petehall347]

f-2806

 

[thesaint]

Sorry again, both r23 and r24 on both F-2806 boards read 47 ohms.

 

[petehall347]

what voltages are at them ?

 

[thesaint]

petehall347, am I again checking r23,24 with those boards pulled at dcv?
You definitely can not get to them put back in because they are buried behind the main Caps.

 

[petehall347]

ah ok .
do the board connectors look clean ?

 

[thesaint]

Yes, very!

 

[petehall347]

looks like you could get to the + side c10 470uf blue ones . then - side of c11

 

[thesaint]

So chassis ground to + of the 470uf live power dcv, both and both and boards?

 

[petehall347]

yes + side c10 470uf . and - side of c11 . black probe on chassis

 

[thesaint]

I only have managed to get to to get to the + side of one. They have this clear sheathing wrapped down the leads, pretty crazy, and it leaves no exposed lead.
It reads 0.0vdc
I will get to the other tomorrow when I can pull the board and pull the sheathing back a bit, crazy hard to get to.
Thanks for hanging in there

 

[thesaint]

Ok, after figuring out better access to those Caps.
Left F-2806 the - of c11 -361.5mv
the + of c10 -351.0mv

Right F-2806 the - of c11 -365.2mv
the + of c10 -354.1mv

 

[petehall347]

they should be about +- 58v
you had the voltages at pins 11 and 18 f-2814 . best check these again to be sure .

 

[thesaint]

Rechecked 11, and 18 F-2814 both boards all read right around -248.0mv

Rechecked F-2806 cap voltages left and right both c-10 and c-11 now all read right at -245.0mv

I did these readings all one after the other.

I have left this powered on now for about an 2HRs or so, don't know if that made any difference.

 

[petehall347]

f-2809 pins 10 and 12 voltages ?

 

[thesaint]

Both pins read -211.2mv

 

[DougBrewster]

FWIW the image of the driver board in post #126 shows it to have the same Molex connector arrangement as the F-2624 driver boards in the 8080DB/9090DB units. It is very easy to mount the board one pin off and blow power supplies/burn up ground traces if that happens.