[Elecraft] Help! Rescue me from stupid error!

[Vic, K2VCO]

Took the second one out. It is labeled TVR07241, which is a 240v
varistor! I can get these to replace them.
I think this one is undamaged (at least, it isn't blown up or shorted). 
I wonder if the other one was a 115V one which was only in the circuit 
when the switch was set for 115. That would certainly explain it blowing 
when I plugged it into 230!

On 9/9/14 8:41 PM, Fred Townsend wrote:
>
> Vic: Sorry you passed the smoke test. Your mystery components sound
> like transient suppressors. They are not needed for normal operation.
> They are there to suppress lightning or other power line
> disturbances. To find out carefully cut out ZNR1&2 and clean up any
> ashes. Then replace the fuse and try the computer. If you are lucky
> the computer will run. Don't forget to change back to 120 VAC
> setting.
>
> Good luck, Fred, AE6QL
>
> -----Original Message-----
>> From: "Vic, K2VCO" <k2vco.vic at gmail.com> Sent: Sep 9, 2014 10:23
>> AM To: Elecraft Reflector <elecraft at mailman.qth.net> Subject:
>> [Elecraft] Help! Rescue me from stupid error!
>>
>> I just did one of the dumbest things I've done since I tried to
>> swim across the Susquehanna river with all my clothes on. I
>> survived that, but I need help with something else.
>>
>> I just turned on a computer plugged into 230v with the switch on
>> the power supply set to 115v. Result: bang, smoke, house breaker
>> (16a) pops.
>>
>> I took the power supply apart (it is a funny size so I have little
>> confidence I could replace it). I found two obviously bad
>> components: 1) an 8a fuse -- no problem. 2) something marked znr1
>> on the board, a component wrapped in heatshrink tubing. It was
>> completely destroyed. Next to it is a similar part labeled znr2. I
>> haven't removed it yet -- so I am not sure it is good. It might be
>> the same as the first one and it might be marked under the
>> heatshrink.
>>
>> There is a bridge rectifier nearby which checks good. All traces
>> look ok. I am hoping there is someone out there who is familiar
>> with these supplies who can suggest what these are (zener diodes?
>> What voltage?) The board is made in such a way that it is difficult
>> to trace the wiring -- but these parts are right near the power
>> input.
>>
>> -- Vic, K2VCO/4X6GP Rehovot, Israel http://www.qsl.net/k2vco/
>> ______________________________________________________________
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-- 
Vic

-- 
Vic, K2VCO/4X6GP
Rehovot, Israel
http://www.qsl.net/k2vco/