• Please review our updated Terms and Rules here

I obtained a very sad 5170...

B

bobba84

Veteran Member
Joined
Jan 6, 2014
Messages
560
Location
Melbourne, Australia
... it has been in a wet shed for years. The motherboard has lots of green residue which I assume is corroded copper. (See images below)

It is complete but some parts are not original. The video card and MFM card seem to be newer, and it has a Seagate ST-238R in it.

May I please have some pointers on what is the best way to remove this?

Thank you!

5170.jpg
5170b.JPG
5170c.jpg

Bobby.
 
It depends on how bad the corrosion is. Rather than wet it down with some water-based solution, as I might if it were due to a leaky battery, I'd probably start with some aerosol contact cleaner and a toothbrush. I use this stuff picked up at my local auto supply store:

p39163.jpg
 
Would you mind documenting your journey on making this sad AT happy again? I'd be interested in seeing if you could restore it/put it to useful work :D.
 
I've had worked on a motherboard in similar shape but it was an Apple Lisa. If you use a tooth brush, you could break off the teeth in the slots if they have been weakened by the corrosion so be very careful. I would soak this board in 1/2 vinegar and 1/2 water for 24 hours. You could very lightly brush it and see how you make out. If the teeth are weak and break, they would have broken when you inserted an interface card anyway but this will tell you if it is restorable.
 
Thanks guys! It's so good to have others with a common interest on here.

I will use this post to mark my progress - I want to restore it to it's former glory if at all possible.

Are you sure it's okay to immerse the whole board in the water/vinegar mix? Should I remove any IC's before doing this? Sorry... I just want to make sure.

I'm going to go to Jaycar today and get some electrical cleaner, I guess after it's had it's bath I'll spray that on and just be as gentle as I can.

I'll let you know how I go!

Bobby.
 
If you're comfortable taking out the socketed chips and knowing where they go back (draw a map and make sure you put them back right side up), I would remove them but also soak them as well. Where there was corrosion, the legs will also have corrosion on them. If the chip legs have weakened, you will lose some of them as you remove them. It really depends on the level of corrosion. In any case, you will have to see if it's worth replacing these. If a lot of chips have broken legs, it might be more economical to find a used/tested replacement motherboard.

In any case, it's worth a try to see how much damage is done. Good luck!
 
You are far more adventurous than I. I certainly wouldn't put much energy into this computer because of the corrosion and rust. But then again, if it was either really, really cheap, or free, then I guess you can't go wrong. I am in the market for a 5170 too, however, if I had gotten something that bad, I would be looking for a replacement mother board, video and hard disc controller. Then I would look underneath the mother board for any more signs of rust. I had one a few years ago that wasn't nearly as bad off as yours, but the corrosion WAS enough that connections in the card slots were easily broken. Some broke off just by gently rubbing my finger across them.

I wish you luck and good fortune and hope your time and energy aren't being wasted.
 
Well, if I was determined to save this thing, the last thing I'd want to expose it to would be water. How do you intend to dry this thing thoroughly, especially with acetic acid reacting. At best, I'd make a 50-50 mixture of isopropanol and distilled water and rinse and dry it. Definitely not vinegar if the corrosion isn't due to a leaking battery--there's no point to it--you've got nothing to neutralize.

If you think toothbrushes are rough, you need a new dentist. The ones that I get from mine are very soft. Use a soft natural-bristle paint brush or an artist's sable brush if you're extremely paranoid.

Don't get your hopes up too high--you may find that some ICs have legs corroded right off. If the corrosion is from rodent urine, you're probably out of luck.
 
Thanks for the feedback guys.

I did get it cheap. So I don't have much to lose by trying. I don't have the finances to spend a lot on my hobby so I have to make do with what I can afford. It didn't have a battery in the case so I'll assume it's not from battery acid. I bought some isopropyl alcohol and some electronic cleaner today, I'll be very gentle with my toothbrush and see what happens. If something breaks, I'll look at replacing it if the rest of the board looks good enough to save after I've cleaned it.

Bobby.
 
I'll be very surprised if you can get this thing running. It looks pretty bad. If nothing else works, I'd try the oven trick on this board. Maybe melting and re-solidifying the remaining soldering matterial would make the connections working, but it won't do anything about the copper corrosion.
 
I'd still give saving the thing a shot- these boards aren't going to get any more common (save for perhaps replicas).

Wouldn't the water and vinegar eventually fully evaporate anyway?
 
cr1901 said:
Wouldn't the water and vinegar eventually fully evaporate anyway?
Click to expand...

What I forgot to mention was the thorough rinsing afterwards. You have to flush it out with water (distilled preferred) to remove any traces of the water/vinegar mix. Vinegar is an acid which helps with corrosion but you don't want it left on to dry. While rinsing, I like to use a soft bristle paint brush to make sure any left-over corrosion or even caked on dust is removed. A tooth brush would work too. This gives the board a good cleaning. I also have a compressor that I use to blow out dust from new acquisitions but in this case I use that to blow out water that could be trapped under soldered chips or sockets/slots. Make sure the board is dry over a few days to make sure there is no water left.

On a side note, I have also tried putting a motherboard in the dishwasher with no soap but that didn't work as well for me. I still had to rinse and brush afterwards.

Whether it's worth it or not, it's a good exercise to try. After all, this hobby is a labor of love.
 
Mother boards can be found on E-Bay for very good prices from time to time. I would like to kick myself in the butt for selling the 5170 I had several years ago. Mine came with all of the vitals attached, even the back plate, and an IBM Model M keyboard. In my case though, I was just barely getting into vintage computing and didn't know what I had.

I wish you all the luck in the World getting your old beastie running again. As for me, well I'll just have to see if I can find one on the cheap, and hope it works. Then all I'll need to finish my IBM collection will be a 5155 Portable.

Again, good luck. Hope I've given you something to think about.

Cheers

~BB~



bobba84 said:
Thanks for the feedback guys.

I did get it cheap. So I don't have much to lose by trying. I don't have the finances to spend a lot on my hobby so I have to make do with what I can afford. It didn't have a battery in the case so I'll assume it's not from battery acid. I bought some isopropyl alcohol and some electronic cleaner today, I'll be very gentle with my toothbrush and see what happens. If something breaks, I'll look at replacing it if the rest of the board looks good enough to save after I've cleaned it.

Bobby.
Click to expand...
 
Looking at your pictures ....I think that corrosion was caused by a leaking battery.
All the PC's I've seen with battery damage had that green/blue color corrosion.
When batteries leak they can produce a gas thats corrosive to surrounding components.
Someone may have removed the leaking battery years ago.

I've had good luck cleaning corrosion from boards with white vinegar and a soft toothbrush.
The vinegar neutralizes the electrolyte, which will prevent further corrosion.
And then rinsing with tap water afterwards.

Is there any similar corrosion inside the power supply ?
 
Last edited:
Mikey, I think that corrosion is probably from moisture; could be from somewhere exposed to salt air. On the bottom, the position of the corrosion--and the green edge connector contacts say that to me.

At least that's the way I read it.
 
if this was a modern computer I'd just buy a new mobo and go from there. There are AT motherboards available, I'd be tempted to replace the motherboard. I have three or four AT motherboards (untested) on stand by should I get an AT that fails. You might want to just clean this one salvage what parts you think might be usable and wait for another AT to come along. My opinion....

[BTW - My Post # "2600" ]
 
Thanks guys.

I tried cleaning the corrosion with both electronic cleaner and isopropyl and neither would completely remove it. It took a lot of it off, but not all.

As it seems to be a no hope situation anyway I chucked the whole thing in a tub of soapy water with some isopropyl in to see what happens. I'll leave it for 24 hours, then leave it for a few days near a warm heater vent.

The power supply seemed fine inside. When I turned it on, the fan turned once then stopped. This repeated each time I turned it on. I vaguely remember these not working without a load attached? I didn't have time to investigate further than that.

Bobby.
 
You must log in or register to reply here.
Back
Top