Re: IIgs Monitor Repair

[Polymorph <polymorph69@hotmail.com>]

On Dec 27, 8:41 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:

<snip>

> If the physical size is compatible, capacitors with higher
> voltage ratings are no problem, and often electrolytics with
> up to twice the capacitance are OK too.  (Electrolytic caps
> have pretty wide tolerances on capacitance, so exact values
> are usually irrelevant as long as the minimum requirement is met.)

OK, I knew you could use a higher voltage capacitor, but I didn't know
you could use one with a higher capacitance. Thanks for the tip! The
problem is, I went to Jaycar today (our local electronics supplier)
and found that they do not stock a 150uF 450V electrolytic cap - the
highest they stock is 100uF 400V, so I didn't bother buying anything
yet until I can source the right caps.

I had another idea anyhow, as I have another IIgs monitor that is
working OK, I thought I might try removing caps from it and use them
in the problematic monitor - trying one at a time until (*hopefully*)
the problem goes away. That way I should be able to isolate the
problem cap and replace only it. It will involve more work, but might
be the best way of debugging the problem? Again, experts thoughts are
welcome - I'm most definitely out of my comfort zone (please remember,
I'm a software guy, cutting his teeth in hardware) and I'm mostly
winging it with educated guesses.  :-)

<snip>

> It may have four "legs" but only two connections--that is, it may
> be just a simple inductor, not a transformer or tapped inductor.
>
> In that case, the problem is just mechanical, and a good indication
> that either someone was poking around in there or the monitor received
> a pretty good physical shock at some time.
>
> If there are wires from the inductor soldered to either of those
> two (relatively) disconnected posts, they should be carefully re-
> soldered.  If not, then just gently re-positioning the inductor
> will improve the esthetics (but probably won't change the behavior
> of the circuit).

My "research" into inductors hinted that this may be the case because
all examples I came across only had two live connections (as I
mentioned previously, I know virtually nothing about inductors).

Thanks,
Mike