[Amps] IC-4KL questions and problem

Gil Bishop gbishop at cox.net
Tue Jan 10 09:10:09 EST 2006


Greetings all,
 I've just acquired an Icom IC-4KL that has a couple of problems.  Hope 
someone can point me on the logical path for tracking them down. All of the 
following occur with the amp connected to an IC-756 Pro II and a dummy load:

1) The power switch on the remote has no affect on the amp - the lights are 
on and the amp is operational in either position, though I do hear a relay 
engage when I press the pwr switch off and on.  Only way to power off is to 
use the breaker.
2) Intermittent failure, generally after the amp has been off (via the 
breaker) for a while.  Key  the XCVR and the amp Ic spikes regardless of 
drive level, no output, and doesn't apparently trip the protection or 
overload (no warning lights anyway).  Will continue this behaviour 
regardless of band for an indeterminant period, then (if I'm lucky) I'll 
hear a weak sounding solenoid engage and everything's "fine" (see item 3). 
If I'm not lucky, it won't correct itself and the only thing I can do is 
turn the amp off and grumble about it till the next time.
3) When the amp is working, on 160-20M I get 1Kw+ out with 50-60W drive so 
at least that's good news.  But just switching to 15M will cause the 
protection to trip.  Once that happens, 50-50 odds the amp will be stuck 
back in condition 2 above...

I'm guessing I've got one or more sticking and/or weak relays.  Your 
thoughts as to which are the likely culprits and suggestions on how to 
troubleshoot would be greatly appreciated!

73 Gil
k1gil
gbishop at cox.net 




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