Hi group,
I've got a friend's Amp supply LK-550 with the optional PAC-5 power supply.
The amp is back for the umpteenth time with melted plates on the tune
capacitor. In
previous visits, I've filed, polished, etc. and it runs for a while. Then it
comes back
with melted capacitor plates. This time, I've replaced the capacitor which is
rated at
3500V. The PAC-5 puts out very nearly 4000VDC, and that doesn't drop much at
full output. That's stressing that poor little capacitor pretty hard. Mistune
a bit, or
forget which antenna you're on, and there is a light show in the plate tank.
I'm thinking of reducing the DC voltage, but I don't have a schematic of the
PAC-5.
The big transformer has an unused terminal on the primary, but I don't know
what it
is. Maybe, it's a primary tap that would allow me to drop the voltage a bit.
I can try
to measure it, but perhaps someone on the list knows, or has a schematic and/or
manual for the PAC-5.
Thanks in advance for your responses.
73,
George T Daughters, K6GT
CU in the California QSO Party (CQP)
October 3-4, 2009
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