IIci will not power on

[bigD]

Hello! A few years back I purchased a recapped IIci here on 68kmla, and it had been working fine until about a year ago, when it stopped powering on. I did the usual removal of all accessories, memory, etc...but there's no response at all when attempting to power it on either from the keyboard or the button on the back. I have a working Quadra 700 so I know the keyboard, cables, and power supply is fine.

I'm not very electronically savvy, but I do own a multimeter and I figure this might be a good way to start learning. Also happy to use this as an excuse to buy more stuff.

Any ideas on where to begin, or maybe point me in the direction of an online resource or thread?

 

[finkmac]

sounds like the person who recapped it didn't properly clean the leaked electrolyte

multimeter is halfway there... i hope you have a soldering iron too?

start by pulling the board out and looking at all the capacitor areas. normally, I'd link recapamac.com.au... but it seems to be down right now

here's the wayback archive. it may not be complete.

see the area on the upper left of the board images? that's where your problem is likely to be.

start off by inspect/cleaning the area around the capacitors. i use 99% isopropyl alcohol and toothbrushes/cotton swabs for that

if that doesn't bring it back, you'll have to start beeping out the various connections using the continuity test mode on your multimeter

see here:

Spoiler: startup circuit

you need to make sure everything here is connected to where it needs to go.


as for the person who sold you this... and it's really not hard to find out who did by searching here... did you really sell it without properly cleaning the lytic?
naughty naughty!

 

[bigD]

Sounds great. Thanks! I'll start working on it this weekend.

Don't want to call out the seller because this thing worked fine for years, which as far as I'm concerned is a win for hardware that's pushing 40 years old!

 

[Byrd]

Yeah, no matter how hard you try to remove corrosion/cap goo from, it can always bite back or degrade long term

 

[croissantking]

did you really sell it without properly cleaning the lytic?
naughty naughty!

Even professionals get things wrong constantly... and we're only hobbyists.

 

[Durosity]

Even professionals get things wrong constantly... and we're only hobbyists.

Yep... I mean how many times have we seen articles posted about manufactures who have installed caps backwards? The LCIII is a prime example of that. Or that time that British Leyland tweaked their galvanisation process to improve rust protection, but actually made the cars rust worse. Or that time that British Leyland... wait.. maybe I shouldn't use them as a good example of a manufacturer.

Suffice to say no repair is going to be able to get 100% of all the nasties that leak out when a cap seal goes. There'll be stuff that hides in vias or under chips that can't be gotten to with even fairly rigorous cleaning strategies.

 

[CuriosTiger]

Did you also recap the PSU? That was the cause of a no-boot condition in my Quadra 650.

You say you have a working Quadra 700, and the PSUs between that and the IIci are interchangeable. I'm inferring from your post that you did try swapping them.

(Other posters have pointed to cap juice damage as a more likely culprit, and I agree. Just thought I'd mention this other, less likely possibility.)

 

[bigD]

Did you also recap the PSU? That was the cause of a no-boot condition in my Quadra 650.

You say you have a working Quadra 700, and the PSUs between that and the IIci are interchangeable. I'm inferring from your post that you did try swapping them.

(Other posters have pointed to cap juice damage as a more likely culprit, and I agree. Just thought I'd mention this other, less likely possibility.)

I can't remember if the prior owner recapped the IIci's PSU, but it works fine in my Quadra 700. I'll start looking at the motherboard this evening and see if cleaning it might help. Thanks!

 

[bigD]

Finally got around to opening up my IIci to get a look at the motherboard. It looks to be mostly in good shape except for this area:



Reading some other posts about motherboard cleaning, maybe a 5% vinegar bath with a toothbrush scrubdown, rinse in distilled water, then isopropyl alcohol, and finally dry is the way to go?

 

[croissantking]

Finally got around to opening up my IIci to get a look at the motherboard. It looks to be mostly in good shape except for this area:

View attachment 98204

Reading some other posts about motherboard cleaning, maybe a 5% vinegar bath with a toothbrush scrubdown, rinse in distilled water, then isopropyl alcohol, and finally dry is the way to go?

Those chips need to be replaced for new - they’re available.

They should be lifted and the pads cleaned up and any broken traces made good.

 

[bigD]

Those chips need to be replaced for new - they’re available.

They should be lifted and the pads cleaned up and any broken traces made good.

Ah bummer - that's beyond my ability. I'm happy to learn, but I'm guessing a beginner should start with something that's not quite as challenging?

Is it a waste of time to even attempt a cleaning? Perhaps I need to start shopping for a working motherboard. My Quadra 700 is great, but I need to get my System 6 fix.

 

[croissantking]

Ah bummer - that's beyond my ability. I'm happy to learn, but I'm guessing a beginner should start with something that's not quite as challenging?

Is it a waste of time to even attempt a cleaning? Perhaps I need to start shopping for a working motherboard. My Quadra 700 is great, but I need to get my System 6 fix.

In that case I would clean it up as best as you can and then use a multimeter to check traces and run repair wires if needed.

I don’t think cleaning alone will accomplish anything though.

Those two HC132 chips do get killed by cap goo but you might be lucky and only have trace damage.

 

[bigD]

In that case I would clean it up as best as you can and then use a multimeter to check traces and run repair wires if needed.

I don’t think cleaning alone will accomplish anything though.

Those two HC132 chips do get killed by cap goo but you might be lucky and only have trace damage.

Cool, thanks. I'll clean the board and break out the multimeter.

 

[finkmac]

for ICs that far gone.. I'd honestly just cut the legs with a nipper, remove the package, and then slide the remaining legs off the board with flux and solder.