Toshiba 26C100U - no power

[ahickman]

Seemed to have made a name for myself. Another TV was pulled from the dumpster and brought by. Symptoms were NO POWER. Opened up the back and plugged it in to the variable transformer. Slowly cranked up the voltage and watched the current jump. I looked for shorts at the bridge and then looked upstream towards the AC plug. Found that the TVS101 ( part number P6KE220CA) was dead short. Pulled it and fired up the set. Works. I have ordered a replacement TVS, but am wondering if there is anything else that I can put in its place as a substitute. Perhaps an MOV?

[tom66]

Re: Toshiba 26C100U - no power

You can only use a MOV in certain circumstances:
- it is safety rated (won't catch fire easily... most are but not all!)
- the fuse can interrupt the failure current and voltage

A TVS device is cheap, try something like this: http://uk.farnell.com/multicomp/p6ke...00w/dp/1578845

Good idea on using the variac. I'm looking out for a TV with a short on the power supply to debug using that as I've got a variac too but not used it for any repairs yet. I suppose you used a clamp ammeter for the current?

[tom66]

Re: Toshiba 26C100U - no power

Oh and are you using an automotive fuse in place of a mains fuse? Bad idea. An auto fuse can only interrupt around 32V, and will not interrupt a mains short.

[ahickman]

Re: Toshiba 26C100U - no power

Suprisingly, the fuse was not blown. The variable transformer I have (Tenma 72-1097) has a current meter on it. Very nice box and if you have the $$$, I recommend it.

Thanks for the helpful advice on the TVS. I have ordered a replacement ($0.77) from Digikey.