mecograph wrote:
Dear Friends,

This is my first post so please forgive me if I break any rules.

I have just picked up a Globe Chief 90 (not 90a) and would like to
begin restoring it. The first thing that came to mind was replacing
the filter capacitor which is 12mfd at 700v. I poked around and
cannot
seem to find any electrolytics in that voltage range that are not the
size of a beer can.

Can any of you recommend a method of substituting multiple capacitors
to make up this electrolytic? Is there a source of these that I've
overlooked? I haven't checked it yet to see if it was bad but I'd
just
feel better proceeding with this project with a fresh filter
capacitor
so I don't destroy the power transformer.
Thanks for any help you can give me,

73,


Derek
WB=D8TUA
Derek, The capacitors that you mentioned are indeed hard to find..
Good news is,, newer capacitors are a lot smaller and more reliable..
Take two 30MF. 450 volts caps and series them ,total will be 15 Mf at
900 V .. I would place a 80 or 100 Kohm resistor at 5 watts across each
cap. to equalize the voltage across each..By the way You can use 40 or
50 MF caps ,this will give you more filtering,better filtering ,which
is a plus..GL 73 W4PQW

wrote:



Derek, The capacitors that you mentioned are indeed hard to find..
Good news is,, newer capacitors are a lot smaller and more reliable..
Take two 30MF. 450 volts caps and series them ,total will be 15 Mf at
900 V .. I would place a 80 or 100 Kohm resistor at 5 watts across each
cap. to equalize the voltage across each..By the way You can use 40 or
50 MF caps ,this will give you more filtering,better filtering ,which
is a plus..GL 73 W4PQW

You took the words right out of my mouth.
So, I'll add something. There is a school of thought nowadays that says
that newer off-the-shelf caps are so consistent that the equalizing
resistors aren't really necessary. That may be true...today. Modern
caps don't have a history of how well they hold up over the years so its
always a good idea to use the resistors even if "it works great" now
without them.

-Bill
(warm spot for the Globe Chief 90, my second Novice rig)

Hi Harold,

Thank you so much for you good advice. I'll get those caps on Monday
and hopefully have some progress to report by mid-week. You are very
kind to help me with my project.

73,

Derek