Mike,
I can't answer most of your questions, but in general the most likely
cause of vacuum relay failure is hot-switching. This could be due to the
design of the amplifier, or the transceiver used to drive it.
K4MGS (Max Gain Systems) <http://www.mgs4u.com/index.html> often has
suitable vacuum relays at reasonable prices.
On 5/28/2014 6:47 PM, mike stokes wrote:
I bought a used Amp supply LK-500ZB. Met the ham on his way to Dayton so I
wasn't able to check it out beforehand. So of course it has a problem.
This amp has the QSK board with a qsk switch on the back. All the
schematics I have seen have 5 relays on the qsk board while this one only
has 3 relays.
There is no continuity from the input to the output when powered off.
Therefore no receive signal passes trough. Also the transmitter goes to
high swr. I know at a minimum that the vacuum relay is bad.
I have the following questions:
Are the vacuum relays high failure ?
Anything that typically causes them to fail.
Any other thoughts as to what might be bad ?
Does anybody have a schematic of the qsk board with only 3 relays ?
Best place to buy a replacement vacuum relay ?
Any other mods or thoughts while I am working on it ?
Thanks in advance.
Mike Stokes
KK9V
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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