K2 dead

[George]

Before supper was working. Left on and went to supper. Came  back from
supper and no display but power is on. No sig heard. Turn power switch  off.
When I turn it back on no display and loud hum in headphones. Then I hear  some
motor boating and headphones go dead. Check input voltage. SW off 13 VDC,  
SW on 4 VDC. Check cable and it is OK. Try another power supply and cable.
Same  thing happens.  Now what?  Help   Geo/W2BPI
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[Don Wilhelm-4]

Geo,

First step --
Take the top cover (or KPA100) off and measure the resistance between
the collectors of Q7 and Q8 to ground.
What is the serial number of this K2?  Alternately, how old is it.
My first suspicion is that the PA transistors have gone bad (shorted),
but your resistance measurement will confirm or deny that.

73,
Don W3FPR

[hidden email] wrote:
> Before supper was working. Left on and went to supper. Came  back from
> supper and no display but power is on. No sig heard. Turn power switch  off.
> When I turn it back on no display and loud hum in headphones. Then I hear  some
> motor boating and headphones go dead. Check input voltage. SW off 13 VDC,  
> SW on 4 VDC. Check cable and it is OK. Try another power supply and cable.
> Same  thing happens.  Now what?  Help   Geo/W2BPI
>  
>
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Please help support this email list: http://www.qsl.net/donate.html