NeXT Computers

NeXT Computer, Inc. => NeXT Work Logs => Topic started by: bobo68 on March 17, 2018, 06:23:27 pm

Title: It's weekend, it's bathing time (or: clean a NeXT mobo)
Post by: bobo68 on March 17, 2018, 06:23:27 pm
Hi,

just wanted to show you how I clean motherboards. In this case it is one of a NeXTstation Color. It did this with several mobo's from ancient Macs and other machines.

Why do this?
Make the mobo look good again by getting rid of dust, grease, smoke particles, etc. which have accumulated over time.

More important: get rid of cap goo (electrolyte from capacitors). Old electrolytic capacitors - especially the can-shaped silvery SMD caps - tend to spill out electrolyte. This stuff is aggressive. It can rot contacts of other chips and destroy the motherboard's traces. It can even get inside the mobo and follow traces of a multi-layered board. If this happens, your mobo is dead.

Before cleaning the board you want to see if some caps have already started to leak. The goo looks a bit shiny and greasy and it smells sour-fishy. If you have some of this stuff on your mobo in the vicinity of caps it is high time to act. i.e. thoroughly clean the mobo and replace the caps.

Here we go:
Detach all removable parts from the mobo like RAM chips, the battery (!) and the ROM chip. Of course you also want to remove drives, cables, the power supply, etc.

https://www.dropbox.com/s/ai15hvzeh08e99x/2018-03-10%2012.22.05.jpg?raw=1

Prepare some soapy water in a tub. The tub should be large enough to let the board completely drown in the water. I use hand warm water and a dish washer fluid used for hand-washing dishes.

https://www.dropbox.com/s/wdy7bi4ceth9dkk/2018-03-10%2012.50.14.jpg?raw=1

Put the board in there an let is soak.

https://www.dropbox.com/s/4sqe6ju8h2uf8jh/2018-03-10%2012.50.23.jpg?raw=1

Scrub the board with a soft toothbrush or something similar.

Let it soak again, then scrub again. Rinse the mobo under clean water and have a look if it is clean. If not repeat the washing.

https://www.dropbox.com/s/6krq57k22wvl4y0/2018-03-10%2012.51.10.jpg?raw=1

When the board is clean rinse it thoroughly with clean water.

Now we have to get the water off the mobo. I use a strong Italian hair dryer with a nozzle in order to blow the water out of every corner, get it out from under the large chips (CPU, ASICS, ...) and dry the slots (RAM, ROM) and sockets (SCSI, monitor, ...). Take your time and do this from different angles so that no water is trapped somewhere. No need to use cool air, the mobo and the components can take some heat and it help to evaporate the water.

https://www.dropbox.com/s/oj5akxdinvbxg91/2018-03-10%2013.20.00.jpg?raw=1

Next: rinse the board with pure 99,x% isopropanol. I think this step it not absolutely necessary but the isopropanol will help to remove water and clean the board even better. You can also scrub the board again and finally rinse it with isopropanol.

Then dry the board with the hair dryer again.

https://www.dropbox.com/s/adfub488msjehte/2018-03-10%2013.29.11.jpg?raw=1

After that you should let the mobo sits somewhere in a warm and dry room. You can also put it in the oven. I used the setting with the warm air blower and set it to 50 degrees celsius (!). Make sure you oven is able to hold the temp and that it is clean inside. You don't want the grease from your last turkey on the mobo. :lol:

https://www.dropbox.com/s/pdj0bc9nvz7l29h/2018-03-10%2013.38.25.jpg?raw=1

That's it. Cleaning a mobo might even be a temporary fix for a flaky board because removing the cap goo can remove short circuits. But eventually you want to replace all electrolytic caps.

---
Update: remove img tags
Title: It's weekend, it's bathing time (or: clean a NeXT mobo)
Post by: krazycat on March 18, 2018, 12:16:09 am
Nice tutorial, thanks. I always wanted to do it, even with Macs, but I'm too scared to ruin something ... (I've never even tried the retrobright, for the same reason)  :wink:
Title: It's weekend, it's bathing time (or: clean a NeXT mobo)
Post by: bobo68 on March 18, 2018, 11:47:36 am
Thanks. I do not why the pictures do not show up in the posting. Any tips?
Title: It's weekend, it's bathing time (or: clean a NeXT mobo)
Post by: krazycat on March 18, 2018, 11:59:08 am
I don't use dropbox links anymore because after their last change of terms of service, I'm no longer able to make my links work on the forums. Now I use postimage.org: it's free and for a sporadic use you can use it even without creating an account. Creating a free account helps you manage many photos posted on many forums.

For your links, removing the tags before and after the link makes the link usable even if you do not see the photo :

https://www.dropbox.com/s/pdj0bc9nvz7l29h/2018-03-10%2013.38.25.jpg?raw=1

Edit: according to this page
https://forum.unity.com/threads/dropbox-users-you-can-still-link-images-in-forums.461996/
maybe on older forum software the ?raw=1 end file wont work and won't display photo preview.
Title: It's weekend, it's bathing time (or: clean a NeXT mobo)
Post by: paolo.bertolo on March 18, 2018, 01:23:15 pm
Interesting, used to do the same, with the exception of the isopropyl step. Reason is that it seems almost impossible to find, so I have used some circuit cleaners available at hobby shops. Where do you source this kind of alcohol?
Title: It's weekend, it's bathing time (or: clean a NeXT mobo)
Post by: bobo68 on March 18, 2018, 04:17:23 pm
Bought it via eBay, e.g. https://www.ebay.de/itm/10-Liter-in-2x5L-Kanister-99-9-ISOPROPANOL-ISOPROPYLALKOHOL-2-Propanol-CLEANER/123001931737
Title: It's weekend, it's bathing time (or: clean a NeXT mobo)
Post by: bobo68 on March 18, 2018, 04:29:22 pm
Quote from: "krazycat"Nice tutorial, thanks. I always wanted to do it, even with Macs, but I'm too scared to ruin something ... (I've never even tried the retrobright, for the same reason)  :wink:


Try it. Many boards will basically destroy themselves if you don't, e.g. the old cube Macs (Plus, SE, ...) are very vulnerable to leaking caps.