A C 4 power aupply info

Glen Zook gzook at YAHOO.COM
Sat Jan 12 23:25:35 EST 2002

I am not sure where to get the "original" physical
sized capacitors (they will probably be expensive).
However, the others are available from Mouser.  For
example, C1 and C2 appear to be 125 mfd @ 450 volts.
Mouser has 120 mfd @ 450 volts for a little over $4
each (the original capacitors are -50% + 80% and those
from Mouser are +/- 20%) close enough for "government
work!  The same goes for the other capacitors.  I
would use 450 volt for most of them.  You will find
the electrolytic capacitors that work fine on page 283
of the current Mouser catalogue.  For example, the 120
mfd 450 volt is Mouser part number 5985-85-450V120 and
are $4.23 in single quantities.  If you use the Mouser
Internet site (mouser.com) you can order using a
credit card.

By the way, in this series of capacitors the part
number is 5985-85- and then the voltage and capacity.
You don't have to have a catalogue to order.

Since C5a and C5b are in the bias circuit, they should
be at least 150 volts (more voltage is better).  You
can replace the dual can with individual capacitors.
The closest Mouser capacitors would be on page 285.
Those would be part number 75-515D160V22 which are 22
mfd at 160 volts.  They are 58 cents each in single

C3 and C4a (100 mfd at 450 volts) would be Mouser part
number 5985-85-450V100 and they are $4.28 in single
quantities (why they are 5 cents more than the 120 mfd
I have no idea!).  For C4b you could use another of
the 100 mfd (it is 80 mfd @ 450V) since Mouser does
not have an 80 mfd capacitor.  Again, remember that
the originals were -50% + 80% tolerance so a 100 mfd
would be well within the original tolerances.

By the way, those from Mouser are about 1/5th the size
(or even less) than the original capacitors.

You can replace all of the electrolytics for $22.41
plus less than $4 for shipping.  These capacitors are
considerably less in size than the originals.

Anyway, if you don't want to spend the money on
"original" size components, this is the way to go.  I
have used the Mouser capacitors in Heath HP-23 series
and other power supplies and they work fine.

I am looking at the AC-4 schematic in the T4XC manual
and there is nothing on it to indicate the voltage
rating of the capacitors.  However, based on the
voltages in the power supply the above should be

The requirements of the T4XC (which the AC-4 has to be
able to meet) are 650 volts @ 400 mA maximum, 250
volts @ 120 mA maximum, -45 to -65 volts bias, and
12.6 volts AC at 3 amps.  The power supply should be
able to do a bit more on the low B+ (250 volts) and on
the filament/heater current (3 amps) since it is also
used to power the TR4 series that have more tubes.

Glen, K9STH

--- "john w. king" <jbkking at BELLSOUTH.NET> wrote:

what is next best? What is the voltage rating of C5A
and C5B? What output voltages does the A C 4 supply?

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