SE no Sound

[falen5]

Working on the second SE board.

The board always starts off with chequred board display - after 10 to 15 seconds it posts looking for the floppy

No sound - no sound on headphones either

I am using the machine i used to fix the other SE board so I have fully recapped analog and psu , good voltages and the speaker works.

the roms and the BBU are also from the other machine so I know they are also good

the sound chip ( the one under the reset switch and has 'snd' printed on the board ) looks like it was either swapped or reflowed.

Im wondering if the 10 - 15 second delay before the machine posts could be caps ?

Ive checked the BBU chip and socket - no corrosion on this socket - cleaned all the pins anyway and reseated the chip a few times.
Did the same for the roms

where else can i look for problems causing no sound

 

[obsolete]

The reset circuit runs through the sound chip. What's the voltage on the reset pin when the system is hung not booting? Does anything happen if you hit the reset button?

It might be worth pulling that sound chip off and making sure that the rework is good and the board isn't damaged around it. If the board is okay, I'd solder in a DIP socket. Replacement sound chips are available.

 

[falen5]

when it stuck a chess board reset pin is a 5 volts - stays there

spent a while doing some testing and timing !!

when i power on the machine I get chess board ........... for 11 seconds , then it posts and boots

when im at desktop and i hit reset the computer just freezes ......... for 11 seconds , and reboots

if i am at desktop and i press reset it freezes - if i press reset again ( before 11 seconds are up ) I just wait another 11 seconds and it will reset

no sound

sound chip 'looks' ok

whats with these 11 second delays !!!

 

[nathall]

The system uses the Sony sound chip to verify voltage has stabilized before proceeding with the boot sequence.

Your two issues are definitely connected. I’d swap out that sound chip and see what you get.

 

[falen5]

Thanks for that nathall

ive recapped the analog board and psu - voltages must be good as the other board boots fine and sound is working on that

Ill have to order one

sony 0f080 , 3430045b is whats written on the chip - nothing coming up on ebay

would you know if there is some modern day chip replacement

 

[obsolete]

You can still get them on AliExpress:

https://68kmla.org/bb/index.php?threads/new-sony-3430045b-sound-chips-on-aliexpress.46506/

 

[falen5]

Thanks for that obsolete

 

[JackRubin]

Make sure that C36 is correct 1uf/50v - Will@CayMac just had a machine that hesitated several seconds on boot and found a 33uF/16v cap in this position. His caps also seemed to be suspicious - labeled 33uf but testing at 50uf. Easy to lose track of the 1uf cap since all the others are 33.