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View Full Version : Help Wanted! Identify resistor on Pink Triangle LPT PSU...



AlfaGTV
26-02-2017, 09:50
I need assistance, someone is bound to have an old LPT in their hideouts somewhere. One of the resistor on my PSU has been overly cooked so it is no longer readable as to what its original value was... Its the one circled in red in the pictures below and here's a closer look first:
http://www.ollars.net/hififorum/resistor.jpg
It has been removed, and measures 40.6 KOhms, which would suggest it was once orange-white-orange, but it does not look that way. If anything it looks like brown-gray-brown of 180 Ohms.. So you see, the options are endless...

Images are clickable!
http://www.ollars.net/hififorum/LPT/LPT_PSU_S.jpg (http://www.ollars.net/hififorum/LPT/LPT_PSU_L.jpg)

Undersidan:
http://www.ollars.net/hififorum/LPT/LPT_PSU_S_PCB.jpg (http://www.ollars.net/hififorum/LPT/LPT_PSU_L_PCB.jpg)

Slutligen, en "sammanslagning" av de båda som kanske underlättar att följa ledningsbanorna om det hjälper ngn:
http://www.ollars.net/hififorum/LPT/LPT_PSU_OL_S.jpg (http://www.ollars.net/hififorum/LPT/LPT_PSU_OL_L.jpg)

Stewie Griffin
27-02-2017, 18:49
It will be 39K [Orange/White/Orange] 5% Tolerance

AlfaGTV
28-02-2017, 06:15
Thanks for your input Stewie!
I agree that is a highly probable value, at the same time the markings sure look brown! :) I dont know what heat does to the colours but assume they will become more "earthy"

Firebottle
28-02-2017, 07:00
Resistors that are overheated do tend to go brown all over, rather quickly if it is a severe overload (:rolleyes:).

See if you can fit a bigger one so it runs cooler :)

Ali Tait
28-02-2017, 08:24
Wot he sed. That board looks to have been well cooked over the years. I'd uprate all that show any signs of heat damage.

dimkasta
01-03-2017, 09:34
Yeah the area around those TO92 critters looks nasty.
I would replace all the high wattage resistors with something like 5W panasonics, and check the transistors' temp as well.
It really looks like something is wrong in there...