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Powerbook 540c won't startup

Iesca

Well-known member
Happy to help! I will probably make a nicer diagram at some point in Illustrator, but in the meantime, the more of these power supplies we're able to save, the longer the blackbirds can be enjoyed!

For now, this particular cap from Nichicon seems to fit the bill for the one on mine that blew, but I'm probably going to just replace all of them (more than one is corroding underneath):

https://www.digikey.com/product-detail/en/UHW1J331MPD1TD/493-14598-1-ND/5818065

Screen Shot 2019-02-04 at 7.32.38 PM.png

 

Iesca

Well-known member
While I still plan on recapping the power supply, I just found on ebay the fabled Lind PB-5 car adaptor for Powerbook 500s!

Does anybody have any recommendations for a good AC to DC power converter for using car appliances indoors? US wall plugs, please!

Screen Shot 2019-02-15 at 5.36.24 PM.png

 
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Iesca

Well-known member
I have one for my Garmin.
Also from Lind? In searching for one before I saw that they are still in business, but I had never heard of them prior to learning about the PB-5. (Also: you still have a Garmin??)

 

Paralel

Well-known member
Also from Lind? In searching for one before I saw that they are still in business, but I had never heard of them prior to learning about the PB-5. (Also: you still have a Garmin??)
I have the parts that go with an old Garmin. I never throw out any power bricks, adapters, etc... (unless they are very common or I already have at least 2) you never know when they might come in handy.

 

Iesca

Well-known member
Disappointing news, it seems the seller was out of stock, and so my order was cancelled. :/

Back to the drawing board... :(

 
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Iesca

Well-known member
Whelp, after replacing all of the caps in the power supply (including the little one on one of the vertically mounted boards), the laptop still doesn't power on. I took pictures of the process which I will upload at some point, but does anyone have any other ideas?

There is a ceramic fuse inside the brick, but no indication as to its value. I know also that apparently the pins inside the laptop can become pushed out of place?

Thank you!

 

Iesca

Well-known member
So, despite the fact that my repair attempt was ultimately unsuccessful, here are some photos I took of the process.

First we have the smaller caps of the board, all of which were in some state of decay, though only one had actually "popped." (These were replaced with same or similar values from Fry's Electronics.)20190313_024130.jpg

After replacing those did not fix the power supply, I replaced the filter caps. Here are the originals, as well as the replacements, which I got from DigiKey.20190331_224421.jpg20190315_181925.jpg

Here are some pictures of the boards. First is the main board, with pertinent joints highlighted. A and B are the 330µf 25v caps, C and D the 100µf 25v, and G and H the 100µf 200v filter caps. (Note that A has been removed already in this picture.)

E highlights the mounting joints of the vertically mounted board that holds the 47µf 25v cap. F is a hook-jointed lead from a ceramic cap on the top side of the board that mounts to the heat sink (bent to the left in the photo).

20190311_134020.jpg

Here are pics of the vertically mounted board with the 47µf 25v cap. Note the orientation of the cap with negative lead towards the notch on the right; it is not marked on the silk screen. (It is the left-hand pin on the reverse side.)

20190313_021005.jpg20190313_021048.jpg

While my effort ended in failure, hopefully these pics will be of some aid to people in the future!

 
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Iesca

Well-known member
Also note that C and D are shorted in various ways! C to an SMD cap, and D to the lead of a diode found on the top-side.

 
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jimjimx

Well-known member
I had the same problem. One day it worked, and the next, it didn’t.  Once I pried open the case and unsoldered the shield, I saw too much black carbon to deal with. And it was too densely packed for me at the time. 

I replaced it with one of these

https://www.ebay.com/itm/GENUINE-IBM-16V-4-5A-AC-Power-Adapter-Charger-OEM/293051877023?hash=item443b40c69f:g:V6AAAOSwX4Bco~OG

The original cable needs to changed from 4 to 2 wire, but it works perfectly now. I forget the colors of the wires that get paired, but there’s a diagram somewhere online. 

Or, if you are going to do this, let me know, and I’ll look at my psu and let you know what I did.  

 

Charadis

Well-known member
The power plugin on the PB 500 could be a problem, but if you leave your computer plugged in all the time, it shouldn’t be subject to as much wear from removing and connecting it to power. Still worth checking. 

 

Iesca

Well-known member
Well, after all was said and done, a working power brick showed up on ebay for reasonable $$ so I just nabbed that and the 540c has been back to life ever since. However, the "new" brick will surely die as well at some point, and so barring a repair attempt with that one as well, I will have to keep in mind jimjimx's suggestion!

jimjimx, if you get a chance, a wiring diagram would be very interesting to see!

This is the relevant page from the PB service source manual, for the curious:

Screen Shot 2019-04-22 at 4.57.27 PM.png

 

Iesca

Well-known member
Also, if anyone repairing one of these suspects they may need a new fuse but don't know what to replace it with, I've taken out the one from my dead supply just to check. I managed to destroy the fuse attempting to remove the lead caps from the fuse itself, but it was necessary in order to see the fuse code on the end.

(Note to self: do not twist from both ends; but hey I guess it wasn't dead! The lead caps are not soldered onto the fuse, it's just a tight fit.) 
 

Fuse Code: F 3.15A H 250V [Fast Acting ("Flink") 3.15 Amp "High Breaking Capacity" 250 Volts]

Dimensions: 20mm Length x 5mm Diameter (technically a hair under 20mm Length, as I measured mine)

Fortunately these fuses seem to be readily available, so even if you break yours like I did, it can be inexpensively replaced: Pack of 5 from Amazon

Just remember to keep those lead caps!!!

20190423_021903.jpg

 
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jimjimx

Well-known member
 

@Iesca

 Here’s the pictures of my toasted PSU, and my slapdash connection of the old PowerBook cable to the new IBM PSU. 

Essentially, Red and Orange to +16V, 

and Blue, Black and Shield, to Ground. 


6DE84623-E63F-4C4F-B291-79A81FD3CD4C.jpeg

C22E8EC3-E95F-4DE4-87B6-E1A7D8741FD2.jpeg

 
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