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techknight

Notice to Powerbook Duo Users!

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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.

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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?

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

 

th_fdf606c1.jpg

 

Higher resolution.

 

That board is like the Milky Way of Vias.

 

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

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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.

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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.

 

c369fb52.png

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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.

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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.

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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.

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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.

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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.

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The notice on leaking caps on the display PCB of PB Duos reminds me to the problem of moribund TFT panels in some PB 180 machines. Did someone investigate if the display malfunction might be caused just by a capacitor leakage and therefore could be fixed?

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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.

 

Use a Dremel and cut the Dock open?

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Well...

 

The recap job on both of the boards went smoothly. No hitches or hiccups on the way. I was pleased.

 

The End!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

That...is what I was hoping for. Ughm...gonna need some tantalums. Not enough room on the display inverter board. PACKED in the display board, up the left side. Oops. We'll be okay. Definitely didn't see the 47uF 6v cap (I used 25v) near the top left corner of the keyboard coming. Can't put the keyboard down. Actually went not tooooo bad...bit of a problem removing the old tanks because of the tight proximity to each other. tsk tsk tsk

 

Pictures...maybe tomorrow. "How many pads did you lift?" Uhmm...ugh...a few

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Thanks for the info about problematic caps. I've got a Duo 280c that needs inspection for this problem. The full Dock had the clicking problem a long time ago, but I never replaced the PSU caps. I did not think it was an operation I could handle myself. More recently, I recapped the PSU in my TiVo DVR, and that was rather easy. The Powerbook disassembly is a bit more intimidating, but I can handle it if I can find a clean surface to work on.

 

Can someone tell me if these issues are symptoms of the bad caps? The Duo runs fine when the battery is inserted and the power supply is connected, but the battery is not recognized. I used to be able to trick the Duo into seeing and charging the battery if I removed it for a few seconds and then reinserting it. That doesn't work anymore. If I remove the battery, the Duo will turn off after a few seconds. The Duo will not turn on unless both the PS and battery are connected. Resetting the Power Manager does not help.

 

Also on the capacitor agenda is a couple of my Quadra 840av motherboards. Hopefully they haven't damaged the MB yet.

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I feel like a complete dufus. It's been a while since I've posted anything on bulletin boards, and now I've managed to do it wrong. I messed up the italics BBCode in my previous post and now phpBB won't let me edit the post to make the correction. Very frustrating. I must be missing something obvious. Is it because the thread is a Sticky?

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I just recapped a leaky 270c but the ticking continues. Anyone kow any other common issues in the DC circuit? I did wash the area with pure Isopropyl to assist prior to install of of the new caps.

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So, as above, except with a Duo 280...I replaced the capacitors and there is still only clicking. Are there other options? I guess I will recap a second time just in case. I hate to let this thing go.

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IIRC the ticking/clicking is just a sign the PSU is faulty, can be anything from a faulty component to a short somewhere.

 

Capacitors problems are related to unstable voltages or outputs becoming too weak at some point.

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