[Elecraft] Help! Rescue me from stupid error!

[Fred Townsend]

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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