Two Sick SE/30 Logic Boards

[techknight]

Got my big bag o caps today from parts express. Low-profile mini radials as well. So, low clearance.

[JDW]

Have photos? Or a link to a photo of those caps?

[techknight]

I can take some. i think they are Lelon brand, audio grade capacitors. I use them for everything and never have a problem. Its local, cant complain.

[CC_333]

I'm eager for photos, too.

If I do this kind of restoration/repair again (and I probably will), I'd like to see the right way is versus the wrong way so I don't make the same mistake(s) unknowingly.

c

p.s. A question for techknight: Aren't tantalum-type capacitors supposed to last longer?

[techknight]

They do. Certainly. BUT I just dont like the fact when they DO decide to fail, they fail violently.

I would rather recap again in another 10 years versus a tantalum blow-out and have a bad board because of it. Its hard to find SE/30 parts now, What about 10 years from now?

[techknight]

As you wish: Pics and what I found wrong.

[nvdeynde]

They do. Certainly. BUT I just dont like the fact when they DO decide to fail, they fail violently.

I would rather recap again in another 10 years versus a tantalum blow-out and have a bad board because of it. Its hard to find SE/30 parts now, What about 10 years from now?

I agree 100%. I use Panasonic FP SMD radial capacitors for recapping: these have low ESR values, almost as low as Tantalums.
I have seen many logic boards were Apple used a combination of Tantalum and radial SMD capacitors so there must be a reason for doing so.
Probably because with Tantalum capacitors their failure mode tends to be by short-circuit.

Anyway, I guess the Panasonic FP capacitors will good for about 15 years.

[JDW]

I guess the Panasonic FP capacitors will good for about 15 years.

The fluid filled caps will indeed last a mere 15 to 20 years. And although it's true that shorts kill tantalums, shorts also kill fluid filled caps too! So when speaking of recapping an SE/30 motherboard, the merits are on the side of the tantalums because the tantalums have no 15-20 year life limit (they can't ever "leak"). The only 2 exceptions are C2 and C11, which are too big in terms of capacity (and voltage specification) to be replaced by tantalums -- you'll still have to replace those every 15 to 20 years.

[techknight]

Yea, Tantalum caps are fine usually but i just prefer not to use them based on my own judgement. Albeit I dont think i have seen very many shorted tantalums. Maybe 6 or so for the 15 or so years ive been repairing electronics. (been doing it since i was a low teen, 27 now). I have seen a crapload of leaky electrolytics both electrically and physically, but i have only seen ONE shorted lytic, and it just so happened to be in a vintage Harmon Kardon receiver of all things, part of the DC protect soft-start circuit.

For the record, I have seen leaky and shorted ceramic capacitors roughly about the same order of magnitude as any other capacitor. Its all a crapshoot. its guaranteed anything electronic will fail eventually. I remember working on the older Hitachi ultravision SD projection sets, and seeing that nicely exploded ceramic capacitor right off the horizontal output transistor in those sets. Always took out the B+ picofuse every time. I even remember seeing a similar issue on zenith sets as well.

Edit: P.S. actually come to think of it, I found another shorted electrolytic. I was working on an Apple multiscan 15" monitor way back in the day, that all it did was power up and shoot a bright squiggly line up the center of the screen and pulsate. Done this every 2 seconds. Turned out to be a shorted and physically leaking small electrolytic and a transistor right next to it in the same circuit. I vaguely remember it being near the flyback in the horizontal stage.

[techknight]

Here is the picture of all the caps I bought locally at parts express. $24.40 total cost.

[techknight]

Anyway. I will start a new thread when I start the restoration and troubleshooting process of these boards. This way its more anonymous, but at the same time, itll be easier to find instead of digging through this thread.

[tt]

Through-hole components for an SMT design....hmmm...might as well get SMT electrolytic ones if you're going through the trouble of repairing the boards.

nvdeynde, do you have part numbers for the caps you used? I might recap my socketed board with the kind you used.

[techknight]

Easier to clip out and remove 15 years later.

[Mk.558]

If you just bend the wires into a J shape, they solder on just fine. Also about 10 times easier to swap and replace.

[techknight]

Well anyway. This thread is officially retired. I have started a new one doing the restoration of these boards. Board #1 is alive and well.

[CC_333]

Good!

I'm glad to hear one of the three boards are working.

I will abandon this topic now, so thank you once again!

c

Edit: p.s. I must admit, it would seem to me that this post has inadvertently served as a catalyst for the emergence of a lot of useful information for those wishing to restore/repair their SE/30s.

[techknight]

Thread is here:

viewtopic.php?f=7&t=17924

[techknight]

All 3 boards are up and running.

[Mk.558]

Version 2.1 released. Should be final release.

http://i26.photobucket.com/albums/c113/ ... 9cbc05.jpg

After much wrangling and making errors uploading to PhotoBucket...

If anybody wants the .cwk AppleWorks document for shameless theft plagarization rip-off rebranding under your own identity "borrowing" copying "I was just reusing it" "I was reworking it" "I was rebuilding it" useful works, just ask.

Extra helping of ink-sogged printer paper is included free of charge. Reminds me of my high school "House" project on Argentina. The tables for economic data were so filled with color and shading like the image that I must have gone through a single color ink cartridge for just that project.

[techknight]

Looks good bro.

Also as a side note, people with no chime no video, or stuck simasimac, check those filter chokes!

Same thing with the failure of SCSI. Check the filter choke!! if something over-draws on the TermPower, it can open the filter choke which cuts V supply to the SCSI IC too!