SE FDHD Restoration

[LaPorta]

Hey everyone,

In another thread, I wrote that I picked up an SE FDHD from a garage sale. MB was seriously Maxell bombed...now trying to clean up the aftermath and get it working again. There are a few parts that need to be replaced for sure:

-One is the MB speaker connector. Those seem pretty generic, is there a good source for those? Mine was literally corroded off the board.

-The little glass C10 was also cooked right off the board into rusty oblivion. These little glass things I am not familiar with. The only markings are that is has a 50V maximum, and is marked as 104 Z. What kind of part is this?

I'll get pics up when I can of progress.

 

[BadGoldEagle]

Welcome to the club!

I had the exact same thing happen to my SE 1/40 (i.e. FDHD with 1MB RAM and a 40MB HD). 





- I don't know about the speaker connector as mine was still okay (the other end of the connector not so much...). Should still be available brand new.

- C10 deals with audio. Mine was dead too so I ended up replacing it with a jumper wire (for now). It's only there to lower the output level of the speaker. Without a wire or a replacement cap, you won't have any audio. But there are probably bigger issues needing to be addressed now.

Can you please post pictures of the hypocentre post cleaning? You will have corroded traces to fix (I had to patch 6 or so on mine). Hopefully the SCSI and the serial chips are still fine. 

 

[LaPorta]

Here is my original post:



I will get post-cleaning pictures up this afternoon/evening. Thanks for the input...now I don't feel so alone! I wish I knew the rating of those tiny capacitors so I can get new ones. I, too, hope the SCSI chip is ok: I cleaned off much corrosion and re-soldered the legs. I wish I had a hot air station so I could remove it and clean it thoroughly, but that isn't so right now. The two filers next to the battery have so much crud bridging their legs that I think I'll just cut them out and put new ones in (I have a pack of spares already, so no big deal).

Any further suggestions?

 

[bibilit]

One of my SEs  was also damaged by a Maxell battery and survived pretty well with some work,...SEs are bulletproof.

Your part is probably a capacitor (0.1 µf / 50 volt)

 

[BadGoldEagle]

Oh yes I remember now! 

The damage around the audio connector is impressive. It seems that the acid melt it out of existence! The serial chip looks fine (one leg was hit but it seems that it the corrosion was pretty much contained). The SCSI chip took a more serious hit. Thankfully you can still get some on ebay if it turns out to be bad.

C10 -> 0.1uF 50V https://www.arrow.com/en/products/com-08375/sparkfun-electronics

C13 -> 33uF 16V axial https://www.arrow.com/en/products/tvx1c330mad/nichicon

Speaker connector -> I couldn't find any online but any bare pcb jumper connector will work

Bourns filter -> https://www.newark.com/bourns/4120r-601-250-201l/filter-rc-network-200pf-25v-dip/dp/39K2504?ost=4120R‑601‑250%2F201&ddkey=https%3Aen-US%2FElement14_US%2Fsearch You need at least one of those but the Mac will boot without one.

First thing is to prevent any shorts... I would first remove the battery holder and then proceed to remove the damaged bourns filter (Bibilit and I tried to remove it normally when I went to him for advice and it didn't work. We had to clip its legs to get it out). Then clean the area again thoroughly. 

Once that's done I would start buzzing out every trace and patch those that are bad (any regular jumper/dupont cable will do). Given the amount of damage, I suspect the big 5V trace/bus is damaged. The VIA was gone one mine.

If you have a spare SE Board (doesn't matter if FDHD or 800k), use it as a reference. The SE schematics aren't complete last time I checked.

 

[LaPorta]

I’ve got an excellent one for reference, thankfully. I’ll get the pics up later, thankfully there was nowhere near as much damage as I had feared initially. The large vias and the other traces, while having bits of their non-conductive coating stripped off, still conduct. Is there a good way to cover them up again?

 

[BadGoldEagle]

OK, good to hear! But there might still be a few bad hidden ones...

Is there a good way to cover them up again?

What you're looking for is conformal coating spray/lacquer. I've never done it and the results aren't especially good looking. But it does protect the board from oxydation.

 

[LaPorta]

Unrelated question: I see you are looking for an SE with stepper motor...what is that, exactly?

 

[BadGoldEagle]

That's the original 800k M5011 SE from late 87 early 88 that says "1Mbyte RAM, 800k Drive, 20SC Hard Disk" on the back. It had a hard drive with a stepper motor hence the designation...

Picture from the web, not my work.

I've got a few B&W Compacts (read a lot) but not all of them. I'm currently missing 3 including this one. I have all the others and some need some repairs (the P200 needs a new EGRET, and the 1/40 I mentioned in my first post.)

 

[LaPorta]

Well it just so happens I have parts of one, including that hard drive. I had no idea why in the world it was as loud as a truck, or why there was some sort of moving part outside the drive!

 

[LaPorta]

Here are the photos of progress so far:

Crud after removing the battery holder:



Cleaning with toothbrush & vinegar, tooth picks, and alcohol:

 

[LaPorta]

Night's work: removal of filters, cleaning, and installation of new filters.

 

[LaPorta]

C13, as you can imagine, was also complete toast. Totally open according to my ESR meter. Replaced it. R6, although it tested good, had a large piece of it's coating stripped off, so that was replaced as well. I keep finding more and more crud underneath these things...I hope there isn't as much hiding underneath the adjacent ICs causing shorts.

 

[BadGoldEagle]

I hope there isn't as much hiding underneath the adjacent ICs causing shorts.

I bathed mine in hot soapy water and went about brushing the legs of every nearby component with a toothbrush. Got all of the acid that might short things off that way.

You did a great job. I would start patching the bad traces now before doing anything else. There are MULTIPLE bad ones. 

To compare our boards, it seems that you got kinda lucky with yours as you were able to solder the new bourns filters right back. My pads were gone so I'll have to patch nearly all the legs of those filters. But then your Maxell damaged the traces near the audio connector, under C13, and under the battery terminal a bit more than on my board.

 

[LaPorta]

I am thinking of just covering the traces with some sort of lacquer as you had stated. As for their integrity, the good thing is that the corrosion was limited to uncovering them: the metal underneath is still good and has good continuity.

Still looking for the speaker connector...

By the way, Eagle, did you see my post about the SE you were looking for?

 

[jimjimx]

@BadGoldEagle 

I thought the glass things were diodes, like this one

https://www.digikey.com/product-detail/en/microsemi-corporation/1N4110-1/1N4110-1-ND/4898967

i also tried to figure out exactly what it is, model, rating, etc, but got no response. 

 

[LaPorta]

@BadGoldEagle 

I thought the glass things were diodes, like this one

https://www.digikey.com/product-detail/en/microsemi-corporation/1N4110-1/1N4110-1-ND/4898967

i also tried to figure out exactly what it is, model, rating, etc, but got no response. 

I initially thought that as well, but when I looked at the lettering, the actual diodes on the board are not listed as "Cx" (x being a number), for capacitor, but (if I'm not mistaken) with "CR" instead. Granted, I do not know for certain.

 

[Crutch]

I don’t have an SE but surely those are Zener diodes? Don’t they have little Z’s on them? (Not that that proves it....)

 

[AwkwardPotato]

LaPorta/BadGoldEagle/bibilit's posts are correct, the little glass things are just ceramic capacitors in a glass case. It was somewhat common for computers to use them around this time period; I know my SE has them too, along with a couple of earlier 8-bit machines. 104 = 0.1uF, Z = +80/-20% tolerance.