IBM 5110 transformer?

[Mattis Lind]

Really good point. Thanks! I will check with my friend.

/Mattis

Den mån 30 sep. 2019 kl 16:46 skrev Paul Berger via cctalk <
cctalk at classiccmp.org>:

>
> On 2019-09-30 3:44 a.m., Mattis Lind via cctalk wrote:
> > A friend of mine is trying to repair a IBM 5110. He is convinced that the
> > transformer is bad.
> >
> > Anyone knows the spec of the transformer?
> >
> > Someone that has a spare?
> >
> > Looking into the tech documentation tell me that the machine requires +/-
> > 5V and +/- 12 V and also +8.5V
> >
> > A very rough guesstimate based on the number of wires from the PSU to the
> > backplane would give 20A 5V, 4A +12V, 4A +8.5V, 1A -5V and 1A -12V.
> >
> > Anyone with a better guess?
> >
> > /Mattis
>
> Does this transformer has a resonant capacitor on it?  They where very
> common on IBM power supplies from that time period and if the capacitor
> goes short you will not get any output from the transformer.  This is a
> lesson I learned as a green service rep 40 years ago after lugging in a
> very heavy transformer for a machine.
>
> Paul.
>
>