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SE/30: Honestly I'm shocked this even turns on...

kaister

Member
I've recently go ahold of an SE/30 in ok-ish condition. Seller said it turns on to a floppy icon and can't boot from floppy or the serial port. I kinda knew it would be a board side issue but the fact it can even turn on gives me a bit of hope so I took the chance.

However, I took the board out and this is what I see:
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Ok, honestly how screwed am I? What's the best way to approach? How do I best way to test when any of the chip in the back half are working?

I'm gonna try to restore and repair the board. I basic soldering skill and board repair experience but haven't worked on something that look this bad. Still I wanna see how far I can take this by myself. What's the best way to clean this board? I wanna clean it first and then reassess what I'm actually looking at. Immediately I already see some missing components with destroyed pad.
 

rickrob

Well-known member
There's a couple of missing components -C5 and UC12. I'd start cleaning the board with a toothbrush and some isopropyl alcohol. get all the crud off the board and then see what it looks like. UC12 is a 75175 line receiver chip and that's why the serial port isn't working. It will need a re-cap as well. The good news is the battery wasn't there so no damage in that area. once it's clean check all the legs on the IC's. Looks like some of them have some corrosion so you'll want to confirm what condition they're in.
 

kaister

Member
The board after wash: IMG_0733.png

Yes, UC12 and Q3 are missing...along with a few capacitors, C5, C9, C10 (I knocked out two cap while cleaning, I was just using a toothbrush.)
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There are a bit of corrosion around the pin of UE10 and UI12, along with UD8 and UE8
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Do you think the UC12 is salvageable:
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joshc

Well-known member
There are a bit of corrosion around the pin of UE10 and UI12, along with UD8 and UE8
This is common, cap leakage causes this. You may have to use hot air to lift chips, clean them and clean the pads and resolder them. Sometimes UD8, EU8 etc need replacing. Those are common parts that are still available new.

Seller said it turns on to a floppy icon and can't boot from floppy or the serial port.
That's a good sign, means the board is mostly working. They probably had a bad floppy. Booting from serial isn't a thing I know of, he probably meant the SCSI port. I wouldn't be trying any of that until you recap/repair the board.
 

kaister

Member
This is common, cap leakage causes this. You may have to use hot air to lift chips, clean them and clean the pads and resolder them. Sometimes UD8, EU8 etc need replacing. Those are common parts that are still available new.


That's a good sign, means the board is mostly working. They probably had a bad floppy. Booting from serial isn't a thing I know of, he probably meant the SCSI port. I wouldn't be trying any of that until you recap/repair the board.
Oh I assume he meant the floppy port, who knows. He mentioned it was sold to another buyer and returned back to him and that's what he was told. I don't think he did anything to it beside turning it on. I did turn it on after I got the SE/30 and try to boot from a floppy emu and did confirm it's not working.

That's when I took the board out. I've already removed UD8 and UE8. Lots of crustiness underneath, however all the pads looks good after I clean that area. Based on the schematics seems like they're part of the video portion. Since I'm not having video issues, I'm cleaning the chip and planning to put it back on.

On the other hand, the pad on UC12 really bad...hard to see but I think lot of the pads seems to be gone. I'll have to check to see where it goes and wire it up manually wire it up. However looking at the schematic...this seems to be going to the printer port? Right? What does this chip do exactly? Is this hard to replace?

UE10 is another chip I'm concerned with but based on schematic, this seems to be related to audio? I might not do anything to it until I get the board to boot.

I might also take a look at the SCSI/Floppy section.

First off, I'm just going clean up and recap the board and put the 3 chip back.

Another thing, what exactly is Q3? Based on schematic, it's a 2n3904 transistor thats part of the ADB circuit. I searched for 2n3904 and they're all NPN transistor with the 3 legs. What's the exact type of transistor that fits in the spot? I didn't test with a mouse so I'm not sure whether the ADB port works.
 

joshc

Well-known member
Some time ago I put together a parts list/BOM for SE/30 boards:

That should help a little bit.

UE10 is the Apple Sound Chip but that is part of the RESET circuit so it is needed for successul boot.
 

rickrob

Well-known member
On the other hand, the pad on UC12 really bad...hard to see but I think lot of the pads seems to be gone. I'll have to check to see where it goes and wire it up manually wire it up. However looking at the schematic...this seems to be going to the printer port? Right? What does this chip do exactly? Is this hard to replace?
UC12 is a RS-422/485 line receiver. Works with the printer / modem ports

I think the board looks pretty good overall, and. UC12 seems to be all there
 
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kaister

Member
Some time ago I put together a parts list/BOM for SE/30 boards:

That should help a little bit.

UE10 is the Apple Sound Chip but that is part of the RESET circuit so it is needed for successul boot.
Nice. I've ordered a bunch parts such as the UC12 line receiver and the Q3 transistor, new caps... and a new binary counter LS393. I accidentally broke off one of the pin when I took UF8 off to clean the pins. I took off 7 chips and somehow this is the only one I damaged. I suspect that pin was already super weak cause the corresponding pin was super dirty...took me a while to clean it. Almost as long as the pads on UC12.

I clean the pads around the UC12 and shockingly all the pads are still there...I originally thought a bunch of them were destroy but it was just super dirty. I clean it a few time with just flux and solder. This is also true for Q3. After taking time cleaning it...it's finally taking fresh solder.

I did have lifted the pad for pin 16 for RP1, both RP1 and UD1 had suspicious pins so I took it off to clean it, I did that along with UC8, UD8, UE8, and UF8 (dirty pins) . Uhh annoying, I don't remember how it happened but I exposed the copper traces next to the pad and I think I should be reconnect the pin to the traces. To make the matter worse, after careful cleaning of every single exposed pads I see after removing 7 chips and all the capacitors, that there is the only lifted pad.

Honestly I'm surprise how little pad damages it has. I mean it did boot up to a floppy icon so I guess it's not all that surprising. Still had no idea why it didn't boot off my floppy emu.

Next task, I'll probably pull up the schematic and make sure the traces around the cap leak are still good and wait for my parts to arrive so I can do the recap. The area around C8, C9, C10 is suspicious.
 

kaister

Member
UC12 is a RS-422/485 line receiver. Works with the printer / modem ports

I think the board looks pretty good overall, and. UC12 seems to be all there
Oh yea should be fine for me to test boot. Though I did buy a new line receiver since I kinda don't trust the one that rusted off. I mean I already need to buy new caps, Q3...and UF8 (I knocked out one of the pin when I was removing it off the board to clean the pads)...so might as well.

I'm more concern about the missing Q3 since this might affect the ADB ports. Do you know what happened if this is missing.

I cleaned up all the pads for UC12 and Q3 and was stunned when I realize all the pads are still there. It was just too dirty for me to confirm it earlier.
 

joshc

Well-known member
Honestly I'm surprise how little pad damages it has
These old boards are tough - they can take quite a bit of abuse. I've had a lot of SE/30s that are flooded with cap goo/grot but they usually come up nice.

One area to check is the caps close to the ASC (Apple Sound Chip) and SONY sound chips as that tends to have some broken traces from all the cap goo:

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