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Battery bombed SE/30 logic board, can it be saved?

romnes

Member
I recently bought an SE/30 that turned out to be battery bombed. I'm looking to buy a working one over at https://68kmla.org/bb/index.php?threads/wtb-working-se-30-logic-board.38400/, but I also want to know if the one I've got can be saved. I'm attaching some close-up photos of the board here hoping someone with experience fixing these boards can chime in and let me know if it's a goner or could be saved.

In addition to D1, D2, UJ3, battery/BT1 (and all the CXX caps) missing, I've removed the UK6 ROM. It's got a couple of corroded pins but otherwise seems okay. Additionally, one of the legs on the UK4 RTC chip has entirely corroded away and it would also need to be replaced.

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max1zzz

Well-known member
Given the large amount of damaged via's I think it might be difficult as it's pretty likely there will be damage to the inner signal planes. It certainly wouldn't be impossible as full schematics are available but would be a matter of tracing out the damaged area using the schematics and running bodge wires to fix the damaged traces.

However, All the custom ic's look good so this board would likley be a very good candidate for transplating to one of @Bolle's replica PCB's once he has finalised those
 

bdurbrow

Well-known member
Just based on the photos, I think it’s fixable; but the results will be rather ugly. You will probably end up with a bunch of bodge wires going from place to place. It won’t be difficult to do (in the sense that climbing Everest is), but it will be tedious and time consuming - you will need to trace out every connection with a multimeter and replace all the missing ones. If you run into signal integrity issues you’ll need an oscilloscope and possibly a logic analyzer (it’s a slow board, so any scope with 40mhz bandwidth or better will do; likewise with a logic analyzer, any USB one will work).

p.s. — I had expressed interest in this board if you had not wanted to pursue fixing it. Since then, I’ve made arrangements to get a near-working SE/30 (needs capacitors - there’s none on the board right now - and retrobright treatment for the case); so I don’t strictly need this one, but if you still want to get rid of it I would be interested in it as a parts donor board.
 

LaPorta

Well-known member
The massive amount of through-hole vias lost in that area is also troublesome. Not insurmountable, but those all need to be made sure to have continuity with the other side of the board. There are a bunch of traces that also appear to need jumpers to be able to function again.
 

craig1410

Member
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Hi - I’m tackling a very similar, battery bombed SE/30 and have managed to get it to boot to the “Welcome to Macintosh…” splash screen after many hours repairing tracks and vias, not to mention cleaning up corrosion damage. The worst thing is that the corrosion renders the solder “unmeltable” if that’s a word. It turns into a grey powder which can only be removed by physically picking it away with a very sharp scalpel point or pin.

From my experience, the broken PCB tracks you can see are a bit like the tip of an iceberg because there will be 10x as much damage below the surface so to speak. I ended up using a multimeter to buzz out all the address bus and data bus lines between the ROM SIMM and the CPU as well as between ROM SIMM and the F258 chips. I found lots of breaks which I repaired with either fine tinned copper wire to repair tracks or enamaled wire-wrap wire to repair the vias by jumping between the ROM SIMM pins and CPU or expansion slot depending on where the break was.

This is my first classic Mac refurb but I am an experienced electronics hobbyist and have a degree in electronics. However, I really was close to giving up by the time I heard the boot chime and got the floppy drive with question mark. I then attached a configured SCSI2SD device to get to the first stage of booting.

Unfortunately the boot process doesn’t get very far but I’m hoping that’s due to the fact my RTC/PRAM chip doesn’t yet have power restored as I’m waiting on some diodes arriving to replace D1 and D2 which were dissolved by lithium hydroxide or whatever is produced by an exploding batttery. I’ll see if I can upload some photos to show just how bad my board was when I got it. I had to replace Y2 and had to remove the RTC chip to clean out the corroded solder from the through holes before tinning the holes and refitting the chip. I also had to reflow the solder on the ROM SIMM holder which was challenging to say the least. Ideally I would have removed it but that’s far from easy.

Anyway, my message is mainly to encourage you but also to make it clear this will probably be a bit of a challenge to get working. I’m not there yet either and for all I know I might never get my SE/30 fully working but it was a fantastic feeling to hear that boot chime late on Sunday evening! Fist pumps all round at that moment! :D

Good luck to both of us!
 

bdurbrow

Well-known member
That's not a battery bomb... that's a battery nuke! 🤯

At that point, I think I would have given in and tried to get ahold of one of the new PCBs that are being made... but, hey - if you can get it going again, great!
 

craig1410

Member
That's not a battery bomb... that's a battery nuke! 🤯

At that point, I think I would have given in and tried to get ahold of one of the new PCBs that are being made... but, hey - if you can get it going again, great!
Haha, I think you‘re absolutely right….but I had a secret weapon….naivety! 😅

Also, I had no idea that anyone was creating new PCBs so I did the natural thing by buying a stereoscopic microscope that cost almost twice what I paid for the SE/30 and a bunch of soldering tips and parts that cost about the same as the SE/30 and then spent my entire weekend fixing tracks and vias! I suspect this won’t be a profitable venture but it sure is fun!

I still don’t even know what I’m going to do with it if I get it working! 🤷‍♂️
 

craig1410

Member
Whenever I see damage like this, the intro to a 'Six Million Dollar Man' comes to mind (I'm a '70s kid).
Gentlemen, we can rebuild him. we have the technology.

I'm a 70's kid too and never missed an episode! :cool:

I just hope my SE/30 doesn't end up running in slow motion like Steve Austin! :giggle:
 

craig1410

Member
Just a quick update to say that I installed D1 and D2 and now have 5V on my RTC pin 8 but still can't boot past about 15% on the progress bar of the Mac OS Starting Up splash screen.

I tried doing a PRAM reset and that seemed to work but still no joy. I tried loading System 6.0.8 onto my SCSI2SD adapter and that behaved slightly differently in that it only briefly showed the splash screen before displaying an empty desktop and empty menu bar. If I hit the programmers button I could bring up what looks like a console where I was able to type text.

I'm currently building a machine specific hard disk image using Basilisk II and also have a set of 7.5.3 boot floppies on their way via ebay so I can try a floppy boot up to see if it's hard drive or SCSI bus related. I might also do a bit more continuity checking on the logic board to ensure all the RAM SIMMs are connected fully.

Will post any significant updates... 😎
 
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