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| SE no Sound |
Posted by: falen5 on 2024-10-08 11:59:15
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 |
Posted by: obsolete on 2024-10-08 12:32:11
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. |
Posted by: falen5 on 2024-10-08 13:48:15
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 !!! |
Posted by: nathall on 2024-10-09 22:00:20
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. |
Posted by: falen5 on 2024-10-10 11:02:46
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 |
Posted by: obsolete on 2024-10-10 11:07:13
You can still get them on AliExpress:
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Posted by: falen5 on 2024-10-10 17:57:00
Thanks for that obsolete |
Posted by: JackRubin on 2024-10-21 20:14:58
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. |
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