Osborne 01 computer smoked..

From: Phil Clayton <handyman_at_sprintmail.com>
Date: Wed Sep 2 06:20:00 1998

> >
> > Hello everyone,
> > I am needing help for an Osborne 01 computer, or some help in
> > repairing it..
> > I just purchased it last week and was using it for about 30 minutes (It
> > had not been used for some 13 years).. Worked perfectly and is in mint
> > condition.. Then all of a sudden a crackle and smoke poured out.. It
> > was still working but I quickly turned it off to save it from further
> > damage..
>
> My first guess (not having seen the machine or the schematics) is that
> the flyback (EHT) transformer is breaking down. Was there any change to
> the image on the screen (flicker/change in size) when the problem occurred?
>
> Examine the flyback carefully looking for cracks/burning
>
> -tony

I checked the Flyback and whole Video assembly , it looks fine on inspection..

  I pulled the whole unit apart and I now know its the Switching Power Supply..

1980 by Astec components LTD.

The board mesures 4 by 7inches and looks very clean, exception of the Cap that
blew, The fuse is not blown either.. LIke I said I shut it down as soon as I
saw smoke..

The Obvoius bad component is the Capacitor (Its cracked on has skicky stuff
leaking out)
The Value is 0,1uF_at_X , brand is Rita, GPC , 250V-MP

On inspection this looks to be the only bad part.. It is next to, in fact
touching against I think a diod or transistor , its black with 3 legs (Wires)
on it (GI KBP-10 8210)..

I am not a professional board level techniction, but I do have alot of
experiance soldering and working with electronic components.. I have basic
tools like: Soldering iron, Ohm meter..
I should be able to reoair this myself with (Like the song goes) "A Little help
from my friends"


So What do you think?
Should I just replace the Bad Cap and plug it in again?
Do you think it blew because of another shorted part ?

Like I said the unit was still working when I shut it down, it was smoking like

crazy tho..

It looks like the standard voltages +12, -12, Com, +5 noted on the circuit
board..

Can anyone help...???

Thanks for your help...

Phil Clayton
Received on Wed Sep 02 1998 - 06:20:00 BST