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I'm trying to fix this Canopus converter so that I can convert lots of old VHS cassettes. The problem is that it turns on for a split (and I mean split!) second, the fan jerks and then.. nothing. I've checked the power brick works. I've opened up the converter itself and been testing for shorts.
The image attached shows the on/off switch (which I've checked works) to the left of the yellow socket. Below the yellow socket is a green block marked 26 with a strange symbol at the front. Putting my probes either end of this block, on the silver parts, gives an open short... -
this tv is throwing me for a loop. do samsung tvs no longer have the backlight self test feature built into the power supply?
i tested the backlight with my LED tester and it lights up both strips. one of them reads 100v and the other reads 63.7v.
unplugged mainboard from power supply but left backlight plugged in, and then plugged psu wall power in. expected to see backlights light up but see nothing.
according to how ive diagnosed in the past, this would almost always be a bad power supply. replacement power supply was cheap like 20$ from ebay. but still i get not even... -
Hello all,
Am trying to figure out this backlight issue with this A1990 Macbook Pro.
Tests performed:
There is no backlight even with a good screen.
Backlight IC is receiving the correct support voltages.
Fuse F8400 ok
Current sense resistor R8400 ok
Backlight IC is receiving 3.3V on enable pin.
Backlight IC receiving voltage from PPBUS_G3H, aprox 12.5V.
Backlight IC receiving 5V from PP5V_G3S
Backlight IC BKLT_SCL and BKLT_SDA both measure 0.545V diode mode to ground
I2C_BKLT_SCL and I2C_BKLT_SDA both measure... -
I got a Yamaha HTR-3065 on the bench currently that's got a no power/ no standby issue.When I plug it in it draws 0.01A from the wall, the relay for the ac transformer never clicks, there are no standby lights on the front, and pressing the power button does nothing. The fuse was not blown but upon measuring the voltages on the power low voltage power supply board (labeled operation 3 pg 89 in the schematic) they do not match what the schematic says they should be.
S9 13.7V
Pwr Ry 0V
AC Det 9.1V
Mgnd 0V GND
The two pins on the transformer for the operation...09-12-2024, 03:04 PM -
This was my initial thread.. https://www.badcaps.net/forum/troubl...-m-at-wits-end
(All the Electrolytics are brand new.)
I started a new one, hope that's ok, because my question is different now! (Strangely enough, after I walked away for a few weeks, it stopped lighting up at all!!)
I am determined to fix this power supply because I have the skills to replace bad components, I just need to find out...
Working...
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