Osborne 01 computer smoked..

From: Phil Clayton <handyman_at_sprintmail.com>
Date: Thu Sep 3 08:19:54 1998

Thank you Tony for your interest in my problem..
I will try to locate a replacment Cap tomorrow or over the weekend..
And I will just replace the defective Cap as you said..
I also agree with you that its probubly all thats wrong with the old machine...

I truly love this computer, finding not only one, but two after looking for quite
awhile was a thrill
and I look forward to some play time with my two Osborne 01's ..

I also want to thank a very nice lady from Germany named Gaby, that also echoed the
same advise as you did on the repair..

Brings up somthing I never considered about old computers that have not been used for
many years.. These two Osbornes were not powered up for over 13 years, they are in
mint condition kept inside for all these years.. I did not know that the years of
sleeping can effect Capacitors..

I am now concerned about the other one, it has an odor like something is hot also in
it comming out..
I have only had the second unit on for no more than 10 mins sofar, hopeing to sort of
break-in the old caps on it without blowing the power supply on it also..

Has anyone else had this problem with old computers befor..?

Again Thank you ..

Phil Clayton


Tony Duell wrote:

> I received your private e-mail to me as well, but I may as well reply to
> this one only.
>
> > I pulled the whole unit apart and I now know its the Switching Power Supply..
> >
> > 1980 by Astec components LTD.
>
> Astec are a very common manufacturer of SMPSUs. They turn up in all sorts
> of machines.
>
> >
> > 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)..
> >
>
> Hmm... The 'X' on the capacitor makes me think it may be part of the
> mains filter network. And these caps fail for no good reason and do no
> other damage.
>
> > I am not a professional board level techniction, but I do have alot of
>
> Nor am I!
>
> > 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?
>
> I'd replace it. A 250V _AC_ capacitor, class X. You should be able to get
> that from a good parts company (alas, being in another country I can't
> help you there).
>
> Then try again. Put the PSU on dummy load if you like (I certainly would)
> - a 6V 6W bulb on between the +5V output and the 0V pin. Let it run for a
> few minutes - taking care not to touch the PSU board as there's mains and
> rectified mains all over it. If it runs for (say) 5 minutes on dummy load
> it's safe to try it in the computer again.
>
> > Do you think it blew because of another shorted part ?
>
> No, I think it just failed.
>
> -tony
Received on Thu Sep 03 1998 - 08:19:54 BST