I joined the Pad Lifter Club

[Mk.558]

Yup.

Just like the M1 Garand Thumb Club, I have now entered the presitigous Solder Pad Lifter Club.

Changing caps on my SE/30 motherboard. Regrettably not as good as this chap,, I lifted a pad. And my solder joints...Well I suppose we'll find out if there's a problem?

What to do now? I looked on the backside and frontside for about 10 minutes trying to chase the pattern. Oh, if it only were so simple...It appears I might have to run a wire to the underside of the board. Or could a small wire to the whatchacallit on the surface which runs down to the bottom of the board work?

14 Megapixel photos below: (And yes, I saw that capaciter I missed near the 470uF)

Also, how do I check to make sure all the caps have good connections? Some are really tricky. The one near the ROM SIMM is easy to check, as is the one near the PDS slot.

 

[Unknown_K]

No big deal.

Find the capacitor with the pad, desolder it. clean the area on the board of any junk and put a drop of crazy glue on the missing pad area. Put the torn pad on the glue in the correct orientation ( so that the pad aligns with the broken trace), let dry. Using an exacto remove the conformal coating over the trace so there is a slight bit of bare copper showing. Reflow solder onto the pad as you would to replace the capacitor (I remove all the old solder from the pads using a copper wick and soldering iron, cleaning it with 100% alcohol when done) while also bridgeing the broken trace with solder. Get a meter and make sure you have continuity between the pad and the other side of the broken trace, then finish recapping.

 

[CJ_Miller]

Congratulations! One of us! One of us!

It is not hard to lift pads, and need not be a problem. On my SE and SE/30 the pads seem to suck up a lot of heat... I used a hot iron with flux-covered solder braid, and also a desoldering bulb. Especially the SE/30 pads, I tried fully melting the solder and nudging them very very gently - and still about half of my pads lifted. This happens more often on older PCBs, especially if they have been exposed to damp conditions for any length of time, such as basement storage. Through-hole caps are IMO easier to replace than SMD.

As K says, just clean everything well and fasten your contacts where they need to be. Also you can tack the new caps onto anything which was part of the same conductive path, such as a pin of an IC or other nearby component, or a via (little silver dot that connects through the PCB layers). With big time board rework, it can help to have the schematics to your mac, but it is probably not necessary.

 

[H3NRY]

Join the club! It looks like the - end of C9 lifted off? Chances are that's connected to ground inside the board, which makes it easy. First, see if you can run a short thin wire from the hole in the board where the pad connects to the capacitor terminal. That's pretty easy. Alternately, measure from the hole to the negative end of C10 or another nearby cap. If both minuses go to ground, there's your alternate connection. To make the most original looking repair, follow Unknown's instructions and glue the pad back.

 

[techknight]

with a controlled heat gun, you could minimize the number of pads being lifted off... however...

I guess the electrolyte eats away the adhesive that holds the copper onto the board.

 

[Mk.558]

Good points y'all.

I got it repaired, some solder paste helped to restore the amount of solder on the pad (aren't they tiny?), scratched away the trace and soldered it. Checks out fine with the multimeter.

The bad: Well the capaciter in question got tossed, and and it just so happened to be near the top of the bin when I fished it out! I thought those kinds of things weren't supposed to happen? Also, the glue held for about 0 seconds when heat was applied. Live and learn...let's just hope she works fine for another 20 years.

Also, Kudos to kragg for including two extra capaciters in the ones I ordered. I would have preferred axial tantalums, as trying to fit these size caps onto a pad which barely fits it isn't quite optimal, but seeing that the guy on the wikipedia picture did it, I suppose that >I< am the weak link...

ETA:

Since y'all helped, perhaps y'all can fight over who gets this sweet-potato nut crisp I just made. Oh wait, I think I might need it for lunch...in that case, you'll have to settle for the standard 3 cookies and a cool point for your efforts. Perhaps we can tag this topic? I searched before I made it and nothing came up.

 

[Unknown_K]

The only pads that lifted on my many repairs were the ones that had major capacitor leaks (and then we are talking something like 2 pads only), it does affect the glue holding the pads down.

 

[JDW]

I find it quite amusing that the 4 photos in your original post are all broken links while your sweet potato nut crisp photo remains viewable. :lol:

I therefore assume the deeper meaning of all this is that SE/30 owners should be sure to eat some potato nut crisp PRIOR TO desoldering logic board caps.

 

[Mk.558]

Ugh good point, I wanted to move the photos out of my main Photobucket directory into a folder, but found out after I moved it that I can't edit my first post.

Oh well. I suppose that means that sweet potato oat nut crisp is the light at the end of the tunnel for us grave-diggers

At least so far, my SE/30 boots, and the HDD isn't making it happy, neither can I boot from the floppy, since I have no Mac FDD. And PCs are horrible at such things...not to mention my Retr0Bright didn't work very well either. Summertime project, we'll say for now. I followed JDW's cornstarch receipe and a UV light, but that didn't work very well. -grumbles-

 

[JDW]

Did you reapply the cornstarch recipe often? I reapplied it once per hour through the course of an entire sunny day. I've done this more than once too, so I know it was not just a fluke. If you don't reapply the gel often, I doubt it will work well, if at all. You've got to keep it "wet" (i.e., in an active RetroBright solution). If it dies it, it will stop working.

 

[Unknown_K]

You are better off going with the liquid solution for items that are not too large (retrobrite). My SE/30's and SE's are slightly yellowed but are even colored so I never bothered to whiten them, they work and thats all I care about.

You do have to be careful with the paste method since it can do some uneven whitening making things look worse.

 

[JDW]

If you apply it as I did, every hour on the hour throughout the day (see other threads where I talk about that in detail), you will not get patchy results. It takes commitment to do the gel method, no doubt about it. But I am in Japan and therefore cannot buy large quantities of H202 on the cheap. Hence, it was impossible for me to dip an entire compact Mac enclosure. That is why I used the gel method. And again, if you do it correctly (i.e., as I did it), you will get great results (assuming you do it on a sunny day).

 

[beachycove]

This is now seriously off-thread, but as I am soon to try retrobright, I will ask anyway: Can the paste not be covered with plastic wrap to keep it from drying out? This is something I have done with paint remover, for instance — not on old computers, I hasten to add, but on doors and the like.

 

[JDW]

You, know that's actually a good idea. I never though about using plastic wrap to keep the gel from drying out. I never tried it but I don't see why it wouldn't work. The gel won't melt the plastic wrap so you should be good to go with it. And since plastic wrap is transparent, and since I highly doubt it has any UV blocking ability, plastic wrap should not hinder the deyellowing process at all. It's worth a try!

 

[Mk.558]

Yes I used the cornstarch receipe, and I don't think the UV light is enough in my case. I got a bit of whiting but not much (it was in the tub for about 10 hours) and it was constantly "wet".

I'll wait for summertime to restart the process. And I did loose some silver paint on the inside. :-/

eta: I would think chemically, (I thought about the plastic wrap idea before) there needs to be frequent reapplication off H202 and Oxi to destabilize the bromide bonds correctly. If we run out of chemical supply, then the chemical reaction could be slowed or halted.

 

[JDW]

Tub? Was it a completely transparent tub? And was the tub made of something that blocks UV light?

I did my deyellowing in the Spring, when UV light intensity is the greatest. It's also a nice time of year because you get a lot of sun but not a lot of heat. Heat will dry the gel faster.

I also used large sections of whitewashed cardboard beneath and around the items being deyellowed, so as to direct even more UV light to them. You can see that white cardboard in my photo here:




I did the same when I deyellowed small items in the liquid form of RetroBright, as shown here:




But I believe the key to my success was frequent reapplication. Again, I did that once an hour. Moreover, I remade new batches of the gel once per hour too! I did not make one big batch at the beginning of the day and use that all day. Another benefit of making multiple small batches is heat. I had to use heat to get the gel to be a gel. And the heat accelerated the whitening action, above and beyond a cold gel. You can read more about that in the description I wrote underneath the following photo:

 

[Mk.558]

Well what I did was to throw the thing in the washtub, suspend a UV light and made a batch with 950ml H202, 4.75tsp (use metric...makes computation easier) OxiClean, and 38tsp cornstarch.

Did it work? A bit yeah. But we'll wait. Right now it needs to boot into an OS, kinda hard with no working boot floppy and all attempts to use a PC with software to install the img were failures. xx(

 

[JDW]

It would appear the sun produces a bit more UV than your electric light did.

Try a test outside on something yellowed. You will be pleasantly surprised.

 

[zuiko21]

Hi all!

I'm in the process of resurrecting my SE/30 and, well... count me in:

:-(

Yes, that's the pad of the + side of C4 (1 uF) -- or lack thereof. You can also see some stuff where C6 was -- it exploded while desoldering it!

Of course, I kept the lifted pad, among the old capacitors, just in case:

BTW, before my Pad Lifting excercise, I managed to skew (?) the + pad of C10:

I've got the proper capacitor set (thanks again, trag!) but I really need to wash the motherboard, like in , so my question is:

May I proceed with washing, or should I repair the pad first? I've read about the repair procedure here, but any advice is welcome.

Thanks a lot in advance!