[sdiy] TX802 Power Supply failure (replacing 3W with 5W resistor)‏

Gordon JC Pearce gordonjcp at gjcp.net
Tue Mar 11 13:08:22 CET 2014

On Tue, Mar 11, 2014 at 04:36:33AM -0700, Gil W. wrote:
> Hi all! I need some help fixing that TX802, thanks in advance !
> My TX802 wan't powering on, I found that Q1 (2SC3559) and D2 (1SS84) were short out (well, I think it was D2 but need to check again...)
> Replaced Q1 with BUT11A (instead of BUT11AF which is supposed to be an equivalent) and 1N4148 in place of the 1SS84 (is that ok?).
> Then I found the wirewound resistor between the diode bridge (R2) and the big filter cap (C12) was dead. This is a 22ohm/3W. I'd like to replace it but the lowest wattage I can find is 5W. Would that be fine or is it too much in that place ?
> Here's the PS diagram:
> http://www.loscha.com/ybb/Tx802-power-A.gif
> thanks very much for the help !!

Higher wattage is fine, as long as you can physically cram it in there.

1N4148 is probably close enough for the diode.

Remember to stick a load across the outputs before powering it on, otherwise the regulator will misbehave.

Gordonjcp MM0YEQ

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