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Recently Acquired SE/30: No Sound/Good Video before recap - Happy Mac Bong/Bad Video after recap

KI5NYZ

KI5NYZ

6502
20250301_164714.jpg

Received a couple weeks ago, and video and rest was working, but no audio. The PRAM battery had not exploded, but all of the electrolytic caps had leaked. The only IC with significant corrosion on the legs was UE8. I recapped with parts from DigiKey, and now I get a loud bong (happy mac) on boot, but the video is now jacked. I have the Console5 analog board recap kit but have not done that work yet.

Was able to remove all of the corrosion, and before starting it looked so bad I thought the legs had rotted completely off. After cleaning multiple times I can see no damage to the legs or pads, but the legs/solder on UE8 is still a little dull. I plan to order UE8 (SN74LS166ADR), UF8/UG8 (SN74LS393DR). See below picture: Can I use the same LS393 for both UF8 and UG8? My ICs are different.

Also, are there any other parts to replace while I'm filling the cart? As you can see the Sony chips have a little blackening on the legs even after cleaning, but nothing was as bad as UG8.

20250301_135726.jpg

20250301_135723.jpg
 
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Just reflowed UE8 and the image is intelligible now! Still not proper, but there's hope.
Are these lines indicative of more pins/traces for UE8 still not making good contact, or is there some other path to go down from here before I order and replace the 3 ICs?

20250301_203328[1].jpg
 
You're close! I'd remove UE8, clean under neath and put back in place. Check all traces going to UG7
 
Probably one trace bad from UE8, but I agree with Byrd, will remove the chip, but will replace it as a matter of fact.
 
Will do, I can see residue from under the chip when under microscope. Need to invest in the components to make a large ultrasonic cleaning basin.
Any tip to safely liquefy the old solder on those small pads? I had to use flux, chipquik, and add new 63/37 just to get the old caps off, and more than once thought I had lifted the pad. None of the cap pads were lifted, and it took more flux and new solder to clean them with wick.
 
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KI5NYZ said:
Will do, I can see residue from under the chip when under microscope. Need to invest in the components to make a large ultrasonic cleaning basin.
Any tip to safely liquefy the old solder on those small pads? I had to use flux, chipquik, and add new 63/37 just to get the old caps off, and more than once thought I had lifted the pad. None of the cap pads were lifted, and it took more flux and new solder to clean them with wick.
Click to expand...
Removed and cleaned. No lifted pads. Same crusted pads as before, but the IC is physically good and completely cleaned it and the pads now. All the vias immediately next to their corresponding pads ping good, and pin 9 pings back to pin 1 fine, and 8 to chassis ground as well.

Will dig into schematic in a couple hours and ohm out the rest of the pads before reinstalling the IC, and hope for the best.
 

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Sigh...
UE8 Pin 15 was open to UG7 Pin 14 at the via next to UE8 Pin 15. Everything else ohmed out. The via wouldn't allow soldering to, so I stuck a short LED leg through it, cut it off and folded over to solder to Pin 15. Now video is perfect, but the HDD doesn't work. It does indeed spin up, but no clicking or activity LED... No shorts to adjacent pins so back go the board...
 

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Well done, you've reached the second final boss! Before finding, without fail, that another component has failed in your SE/30 and needs replacement.
 
KI5NYZ said:
Sigh...
UE8 Pin 15 was open to UG7 Pin 14 at the via next to UE8 Pin 15. Everything else ohmed out. The via wouldn't allow soldering to, so I stuck a short LED leg through it, cut it off and folded over to solder to Pin 15. Now video is perfect, but the HDD doesn't work. It does indeed spin up, but no clicking or activity LED... No shorts to adjacent pins so back go the board...
Click to expand...
The HDD might still stand a chance but it will be hit or miss. The drive head parks itself against a rubber stop which over time becomes goop. I have successfully opened the HDD's and voided the warranty (LMAO) so that I could gently move the head away from the rubber stop and then added a bit of Kapton tape over the deteriorated rubber so that the head would no longer get stuck. It has worked twice of the three drives I have done this to. Doesn't hurt to try and if all else fails, a SCSI Drive emulator like the BlueSCSI or Zulu would be your best bet.

Keep us posted and great work on the repair!
 
KI5NYZ said:
Sigh...
UE8 Pin 15 was open to UG7 Pin 14 at the via next to UE8 Pin 15. Everything else ohmed out. The via wouldn't allow soldering to, so I stuck a short LED leg through it, cut it off and folded over to solder to Pin 15. Now video is perfect, but the HDD doesn't work. It does indeed spin up, but no clicking or activity LED... No shorts to adjacent pins so back go the board...
Click to expand...

Have you checked the fuse F3 on the logic board? It commonly blows and could account for the issue you’re having.

Agreed that a ZuluSCSI would be a good replacement for a failing drive, otherwise.
 
Have the ZuluSCSI Pico Slim, and just ordered a FloppyEMU....But I already shipped off the board to Caymac a couple weeks ago for his reloaded logic board service. Hopefully get a YT video out of it so I can see what else was wrong. I do have the HDD still and will try opening it up, but only if after receiving the reloaded board it still doesn't work. In the meantime I have a BabyFace PSU to swap out, the Console5 analog board kit recap, and reflowing the joints on the analog board.

Will post the video link if he makes one of my board.
 
Just received my reloaded board. Installed 128mb new ram from Caymac and Garrett's ROM set to 7.1 mode. The mac boots from the original drive fine, I get the happy-mac bong, and the error beep once fully booted and the System Profiler error pops up. ADB is not working on either port, for either the mouse and kbb, but they were working on my original board. I cannot use "R" while booting to get the custom ROM menu. My Mac-O-Meter shows +12v and 4.97v fine, but -12 does not light up.

While the logic board was away, I re-capped the analog board, reflowed all of the pads, and replaced the PSU with a babyface one. Will check the psu voltage when I find the pinout, and trace it from the psu to the analog board, and analog board to the logic board to see where the -12v is lost.

Also need to figure out where I went wrong with building the 7.5.3 image on SD card for the zuluSCSI, and how to make the floppyEMU work. Booting from the external zulu with the internal HDD disconnected, it boots to the Welcome to Macintosh screen, but hangs there and does not load any extensions at the bottom of the screen. Selecting any installer or HDD image on the floppyEMU with the HDD and zulu disconnected only presents the floppy w/flashing ?. The custom 7.5.3 image boots in Basilisk just fine.
 
KI5NYZ said:
Just received my reloaded board. Installed 128mb new ram from Caymac and Garrett's ROM set to 7.1 mode. The mac boots from the original drive fine, I get the happy-mac bong, and the error beep once fully booted and the System Profiler error pops up. ADB is not working on either port, for either the mouse and kbb, but they were working on my original board. I cannot use "R" while booting to get the custom ROM menu. My Mac-O-Meter shows +12v and 4.97v fine, but -12 does not light up.

While the logic board was away, I re-capped the analog board, reflowed all of the pads, and replaced the PSU with a babyface one. Will check the psu voltage when I find the pinout, and trace it from the psu to the analog board, and analog board to the logic board to see where the -12v is lost.

Also need to figure out where I went wrong with building the 7.5.3 image on SD card for the zuluSCSI, and how to make the floppyEMU work. Booting from the external zulu with the internal HDD disconnected, it boots to the Welcome to Macintosh screen, but hangs there and does not load any extensions at the bottom of the screen. Selecting any installer or HDD image on the floppyEMU with the HDD and zulu disconnected only presents the floppy w/flashing ?. The custom 7.5.3 image boots in Basilisk just fine.
Click to expand...
Was a loose ADB filter module. Re-seated it and it's working great!
 
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