[Amps] Alpha 77DX

[George]

Hi Dan,
I have a 77SX and if you find a place to buy those switches let me 
know.  I would not be comfortable using the amp without the switch 
unless I put a HV fuse in line with the B+ and probably a current 
limiting resistor in line with the B+.  I had a failure of one of the 
doorknob capacitors in the RF section last spring and that solenoid trip 
the rig off and prevented serious damage.  Best of luck finding 
replacement switches.
73, George
W2GS
On 10/20/2013 4:13 PM, Dan Hearn wrote:
> After 17 years of reliable service the set of 4 push buttons on the right
> front refuse to latch when pushed in. Of course the amp will not turn on
> then.
>    The manual says that there is a solenoid below, mechanically connected to
> the switch, which will unlatch the switches if the plate current is
> excessive, turning the amp off
>    I used a piece of buss wire, formed into a hook, to lift up slightly on
> the solenoid core and found that then the switches operate properly. I
> believe there may be a spring in the switch  to counter the weight of the
> solenoid core when it is not energized. I believe one could rig a small
> spring slightly off vertical to help lift the solenoid core but I feel
> comfortable without the safety feature.
>    I am considering disconnecting the solenoid mechanical pull wire and
> using the amp without the plate shutdown feature. Replacing the switch
> would be a difficult job. I will probably order a spare switch since both
> of the switches on the left and right sides may fail completely.
> . Has anyone faced and solved this problem by this means or some other?
>
> Dan, N5AR
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