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PowerBook Duo 230 - did I kill it?

8tto

Active member
Hi!

I have a PowerBook 230 with two power bricks. Last time I turned it on was half a year ago, just to see if it still worked before I trying to sell it locally. Then the condition was unchanged from before I put it in storage: all ok, but some flickering on the screen and vertical lines across the screen from white windows. No one was interested in buying. So after reading a lot on this forum about recapping, I thought I might as well give it a try. And of course it was long overdue: the printer port was almost loose from the PCB from corrosion.

Just for fun I also recapped one of the power supplies. 

Sad thing is, now the PowerBook won’t turn on: there is no sign of life whatsoever. No sound, no smell nor smoke, just a faint hum from the recapped power supply. The original is dead quiet but leaves the 230 just as lifeless. Of course I don’t remember witch one I used last time it powdered up - or if I tried both.

So to the first question: I measure no voltage on either of the power supplies: nothing on the power plug on either, nothing on the pcb connector on the power supply I’ve opened up, and nothing on the connector on the 230 motherboard. There’s no current on the outside connectors on the power bricks either.

Is this normal? Shouldn’t there be 24V on some of the pins?

I find just som mV on the motherboard (don’t know where to look), but 2,5 - 3 volts on some of the pins on the expansion board for the power buttons when plugged in.

 

8tto

Active member
I`ve later found pictures with caps from the motherboard and screen in different threads here, but not the powersupply. I`ll post the ones I`ve made anyway.Duo Power caps.jpg

C16 is inside a plastic cover and have to have exact dimensions and lead spacing. Altough not inside a plastic cover, measurments on C5 is also critical.

Here`s my motherboard with the old caps.

Duo_caps.jpg

I placed the serial port where it was supposed to be. Actually it was only held in plasce with one ground tab only.

And here`s the screen:

Duo_screen_caps.jpg

These are plastic encased alu-electrolyt caps according to @techknight and this thread: 



Here @superjer2000 used ceramic caps for the replacment. I tried the same caps, since it seems it turmed out good? But I`m a little befumbled as these seem to be non polarised?

They where easier to replace when removing the metall casing around the screen.

I`m not sure how my work turned out since my PowerBook won`t start.

Edit: please let me now if I`ve made mistakes in the photos!

 
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androda

Well-known member
the printer port was almost loose from the PCB from corrosion.
Ouch, that sounds like a rather extreme example of corrosion.

Given that you measure basically nothing coming from the power supply, there are several possibilities.  It could be that inside the mainboard there's a short to ground; this should cause the power supply to go into current limiting mode (drops the voltage) and often they cut out entirely if a short is detected.  This one may be fairly likely given you said the serial port was dangling by a thread - who knows what has been corroded and is now touching ground or power which shouldn't be?  Maybe the power supply itself has an issue and is not producing power.  Could be a short somewhere from your capacitor rework.  Maybe a component on the power supply has died, like an optocoupler or the switching driver?

Check the underside of the board for gunky black stuff, that's an indication of where cap goo has been burned from current flowing.  Often near vias and things.

 

superjer2000

Well-known member
Here @superjer2000 used ceramic caps for the replacment. I tried the same caps, since it seems it turmed out good? But I`m a little befumbled as these seem to be non polarised?

They where easier to replace when removing the metall casing around the screen.

I`m not sure how my work turned out since my PowerBook won`t start.

Edit: please let me now if I`ve made mistakes in the photos!
Correct - if you bought MLCCs (i.e. ceramics) they are not polarized.

With regards to your system not starting up, you should be able to measure output on the power supply to rule that out without it being connected to the duo but it might be a bit of a process - if I recall, the connector is like an audio plug where you need to find a way to attach a probe to the + and - on the same inside stem without shorting it out.

If the PSU is putting out the right voltage then it's a lot harder to troubleshoot given your comments about internal corrosion - I don't recall seeing any corrosion or caps leaking on my Duo, other than in the screen - You might have a number of other issues going on there.

 

8tto

Active member
Hi! I appreciate your answers!

The Duo powerbricks has terminals one the outside for a separate battery charger so it’s not that hard to measure. There’s  continuity between the cable and these terminals and no power here either. I tried measuring my known good PowerBook G4 and MacBook Pro powerbricks when plugged in without connecting the laptops, and didn’t find any current. (The G4 one seems to have the same plug and voltage, but I’ve read somewhere here that it’s not compatible with the Duo’s. Is the pin-out different?)

So with slim knowledge I’m guessing all of the supplies won’t supply any current without being connected to a computer that replies the right way?

If so, it’s more likely to be something wrong on the motherboard. I’ll take it out again and study it closer.

Someone mentioned small fuses one the solder side of the MB. How do I recognise these? I can upload pictures of the MB when I’ll get it out again. Thanks again!

 

superjer2000

Well-known member
It was a long time ago that I recapped my Duo AC adapter so I can't say for sure but I thought I had checked the voltages before plugging it into my Duo.  To clarify, you confirmed continuity between all "outputs" on the duo plug though (the two (or three?) on the inner pin plus the outer shield against the battery  charger terminals?

 
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androda

Well-known member
(The G4 one seems to have the same plug and voltage, but I’ve read somewhere here that it’s not compatible with the Duo’s. Is the pin-out different?)


The G4 plug is not compatible because it's a smaller diameter.  A G3 powerbook adapter would work, I've used them before on my Duo.  Note that the common yoyo adapter has two styles, one for iBook G3 and one for iBook G4.  The G4 style has a darker grey plug which is smaller diameter, and the G3 one has a lighter, more clear plug which is the larger diameter.

 

8tto

Active member
Its not dead!

Washed the board with isopropyl alcohol and a toothbrush and rinsed in tap-water (I know this is wrong) and let it dry a couple of days.

It booted when put in the powerplug. A shriek from the corner of the MB with caps before booted fine and reached the desktop.

The unpolarised ceramic caps in the screen seem to be working fine. But I`m a little disappointed that the screen still has pronounced ghosting and lines.
Turns out the contrast knobs on the screen doesn`t do anything (I guess they didn`t before my tinkering either).

And my recapped powerbrick does nothing but hum - no juice. The powerbrick I didn`t recap has connection issues where the 220V gets in. When the machine is running I measure 4.4 and 23.4 Volts at the outside terminals.

 

stevenh

Member
The shriek is the inducers/coils? I've asked if there's a part we can replace with nowadays over here:



The left coil is making the noise and sometimes it seems to 'charge' enough to shut up and let the PowerBook boot.

 

8tto

Active member
Yes, it might be. I was wondering if the low voltage from my powerbrick is making these coils struggle at startup?

Mine are looking a little better than yours and have a different number on them. But Google won’t help me find our what they are.

 
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