Notice to Powerbook Duo Users!

[APE]

For anyone paranoid: be very paranoid.

This same thing is happening on video game hardware too left and right. I had to recap a Nintendo as the caps for sound went out and I had to max out my amp just to get it to normal levels. Game Gears are dying left and right because of caps as well as Turbo Expresses, Super Nintendos, etc. Only a matter of time before caps die (obviously a bit hard for ceramic disc to do much) and at worst they will take nearby traces with them.

The good news is that often times you can find physically smaller capacitors as replacements than what was originally used in Apple hardware.

 

[Mk.558]

If I did a Duo recap guide, I'd have get the schematics. I sifted through the Apple Service CDs I have and I didn't see any schematics, and I doubted there would be. Most just service manuals, MacTest Pro, random this and that and so forth.

Well, I wouldn't have to get the schematics, but I'd have to know what the + and - pins go to. That's kinda hard, because it's not well-known how many layers the board is, and the components are smaller than the SE/30 or a Mac II board, which is comparatively spacious, if not luxurious

That said, I'll do my 2300, but I first have to worry about some other things for it (battery recell, PRAM battery, CF adaptor, display housing, and more RAM).

 

[techknight]

When I get some spare time, I can help out with the capacitor pin connections.

 

[Mk.558]

CAPTAIN! CAPTAIN!

What is it soldier!?

MORE ENEMIES!!!

What and who is the culprit?

A DUO 2300! The 230 returns clean!

Good job soldier! A+ to whoever broke the plastic retainer thingys, you can see them near the hinges, the female end has been broken off the display back. (If you have have a proper replacement, hit me up)

 

[Mk.558]

Can u haz got MiniDock?

Two 35v 100uF caps with a pair of 16v 330uF tanks await you!

 

[techknight]

I dont own a minidock.

I own a DuoDock. last I used it, it worked. But its missing the floppy drive and assembly/cable/bracketry.

 

[Mk.558]

Hopped down to the electronics store.

Got most of what I needed, sort of: it appears that the tank farm is spec'd out to 105 deg C caps.

Got 4x 100uF 35V caps, 1x 100uF 25v, and one 35v 47uF. Good news: the replacements are smaller than the originals at the same rating.

But I don't know what "33 EHA 5B7", "50v 2.2", "g2 10 50v", "5S 68 10v", or "e3 47 6v" are. The voltages are obvious, the capacitance is not.

 

[techknight]

Yea they are, they are in plain english.

"33 EHA 5B7", "50v 2.2", "g2 10 50v", "5S 68 10v", or "e3 47 6v"

33uF 2.2uF 10uF 68uF 47uF

 

[Mk.558]

So those random characters are manufacturer codes?

What is the voltage for the "33 EHA 5B7"?

 

[techknight]

I would assume so, on the manufacturing codes.

must be another number on that cap somewhere, as voltage isnt listed.

you can easily figure out what the voltage is depending on where it is in the circuit. It might even be non-polar?

 

[Mk.558]

Nah there's a tiny + sign near the area relevant to it. There are two of them on the motherboard. C41 and C94.



Higher resolution.

That board is like the Milky Way of Vias.

I'm banking on 16v. No idea, though. Or 10v.

 

[techknight]

Well thats a good one actually.

It could be 33uf at 5.6v.

But it could also be 0.33uf at 57V. But i dont think so. I am betting on 33uf at 5.7V

Grab a meter and measure the DC at that cap during operation, thats how we will know for sure.

 

[Mk.558]

Checked with a voltmeter with the power on. A steady 4.96 to 4.97 volts. Bam.

This means it's probably a 6v unit. I'll probably go with a 10v to be safe? I mean the thing was in pieces, the display was connected and on, trackball, a SCSI HDD, UltraDock, external FDD, no modem card, and a paltry 4MB RAM card.

From the very limited accurate information online, "5B7" refers to a case size. Which is about right since it's about 6mm x 7mm...ish. The actual voltage rating can be 4V to up to 63V. source

Since it says "33 EHA 5B7", 33 probably refers to ...I dunno, there's a possible match at 10v 33uF with a 5B7 case size. I don't care about the case size because of what I'm replacing all my caps with (electrolytic), I care about the capacity and voltage.

 

[techknight]

Well with the measurements you gave me, that cap is part of the 5V rail. So a 6.3v cap or a 10v cap would be fine.

But if it were me, i would get a 33uf at 16v.

 

[nvdeynde]

I own a DuoDock. last I used it, it worked. But its missing the floppy drive and assembly/cable/bracketry.

Have you taken a look inside the PSU. It's recapping time there as well.

 

[nvdeynde]

Well with the measurements you gave me, that cap is part of the 5V rail. So a 6.3v cap or a 10v cap would be fine. But if it were me, i would get a 33uf at 16v.

I replaced them with 33uf, 25v: given the power supply is at 24 volts, you're 100% sure it works.

I have recapped all my Duo's a while ago and use them regularly without problems. Always use a higher voltage when you're not sure.

 

[techknight]

Not exactly. Maybe in this case, but not all cases. power supply may be 24v, but there could be a 40v boost in there somewhere to feed passive panels. Now sometimes this voltage is built into a DC-DC circuit on the panel.

So dont take that for granted ;-) My previous point stands that it depends on the circuit.

 

[Mk.558]

At what point would too much voltage rating effect the caps intended properties?

 

[techknight]

probably never. if your running a 50v cap in a 2v circuit, it isnt going to make a difference i dont think.

Now, running a 2v cap in a 50v circuit, well, you would have to try it.

 

[APE]

I've got both a Duo Dock and a mini Dock. Shame my Powerbook is stuck in the Duo Dock and I don't have the key.

I'll just have to find me a pick gun and have at it I guess.