Compaq Portable - Help

[antnik]

Hi to everyone. I am searching this kind of transistor (photos). I dont know the type of transistor and i cant find any info. Can somebody help me? This Psu is from a Compaq portable https://i.ytimg.com/vi/2YO-BCqPqs4/maxresdefault.jpgcomputer . Do you know if schematics are available for compaq portable?
Thank you in advance.

 

[JackKnifeBarber]

Service manual

Service manual

Here found somewhere else on this forum. Not very helpful for Q3 though. Lists it as a 508 with no replacement data. Hope it helps with the detective work.

http://download1321.mediafire.com/q.../Compaq+Portable+Service+Manual+-+cscs-15.pdf

 

[3pcedev]

You could try purchasing the SAMS computerfacts for the compaq portable. They will most likely have a schematic for the PSU in them.

I had a look on SAMS website and they still offer it for $22. Link here

 

[dabone]

Ok, so no clue on the cross, apparently I chose poorly last year, which is why my repair failed.

It's labeled just 508.


Here's a link to the service manual.



http://www.svfdtn.com/mtx/Compaq%20Portable%20Service%20Manual.pdf



Later,
dabone

 

[3pcedev]

Based on the schematic posted above it's just a BU508 power transistor. Still readily available.

 

[antnik]

Hey guys. Thank you very much for the support. I was looking for this pdf but i couldn’t find it. Thank you very much. Before i read your answers i replaced the transistor with BD139 and i also replaced the diode next to it which was bad. After i replaced these components the psu worked with all voltages. Unfortunately one tantalum capacitor on cga exploded so i have to replace all these capacitors. Now with this pdf i will examine better the psu and i ll check all the computer.
Thank you again for the support all of you. !!!!!

 

[mborza]

Hello, I have a problem with an identical power supply. The power supply starts and has the correct voltage for 20-30 seconds after which it power off. If I power on the power supply without load , the voltage tend to remain stable, but as I add a important load(big HDD) voltage begin to fall and the power supply stops. I changed the capacitors on the output but in vain.Some suggestions?