Don -
The cap under the transformer is for the 5V supply for the calibrator. Not
likely to be the problem.
The large silver can is _almost_ certainly the culprit. There are other possibilities of course,
but ...
You can check with an ohmmeter, start with the Twist-Lok cap terminal with the two white/blue wires
on it. Again, this is the 'most likely' spot. Connect you meter from that terminal to chassis.
The meter should show a very low resistance at first, and then start increasing. It should read 5 -
10 k ohms, depending upon many factors. If it reads in the low hundreds of ohms, probably bad.
Beyond this requires either disconnecting the wiring to the various terminals or an ESR meter. If
you decide to disconnect the wires, I would strongly suggest cutting them as close to the terminal
as possible. The wire Drake used is extremely sensitive to heat and will melt or 'crawl back' quickly.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
www.k4oah.com
Don Rasmussen wrote:
Hey guys,
The fuse blew out on my R4B today. There are 2 filter caps that I am
inclined to check, one is mounted underneath the power transformer,
the other is the larger silver can mounted above the chassis. Can
these be tested with a simple VOM? What readings to look for -
shorted? Also wondering what else to test before tossing another fuse
in line.
The wiring attached to the NOTCH pot also seems to be disintegrating
all by itself - interesting.
Thanks,
Don Rasmussen
Carlsbad, Ca.
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