Repaired the PSU QX801, QX802 together with associated smd resistors and smd diodes. When powered up everything fine but after a few minutes transformer TS801 and TX801 began to hiss more than usual. After 10mins psu had failed again just repaired it again but after a few minutes once again the same transformers are hissing more than usual. Switched it off again now in case it fails again. Anybody any ideas why transformers are hissing or is it just due to ageing transformers? I have repaired a number of these power supplies in the past without any such problems.
-
-
Re: PS50Q97HD PSU repair bn44-00162a
Any replies re above appreciated! -
Re: PS50Q97HD PSU repair bn44-00162a
I think good quality pictures of the power supply board would definitely get you more attention. Reason being is that very few people can/will look up the model number and then try to fetch a service manual for the PSU to look up what those parts you mentioned do. I, for example, rarely look up service manuals, because I'm bad at finding them and I usually have an easier time understanding what the circuit does by looking at it than trying to figure it out from multiple pages in the SM.
As far as those transformers hissing - are these for the backlight inverter or the main transformer. I'm only guessing the latter.Last edited by momaka; 07-03-2014, 08:38 PM.Comment
-
Re: PS50Q97HD PSU repair bn44-00162a
That particular power supply after being repaired a second time is now ok. Having said that the VA transformer still continues to produce a louder hiss than normal.
There doesnt appear to be any cracks on the ferrite and all voltages are as they should be. It doesn't become noticeably louder until after about 5mins of running. Thanks for your reply.Comment
-
I've been using this monitor for last few years.
Symptom started by OSD menu popping on and off randomly by itself. So i tried to clean the touch control area with some cloth but it didn't help.
After 20 minutes monitor started hissing from the back. And then 30-40 seconds later screen started fade off/on like as if i was turning down the brightness that's when i turned it off by power button (hissing stops) and replaced it with spare monitor.
Today i opened up the monitor, excited to repair my first monitor (or big electronics) hoping it's a bad... -
Hello.
GPU came in, green lines. Spent lots of time using to get the Mats / mods drive working (found on youtube).
Found issue with a RAM block
Replaced, green lines gone.
Trying to test again, assuming getting the false positive. Originally had over 1K on a single bank. Now getting tosses low between banks.
Used a good card to test and same results low errors 32+.
I am just search for some form of command to do a full test on the GPU.
I just ran the mats command with my good GPU and passed after roughly 40 min.
The repaired one, ran... -
Hello there, got a Thinkpad E15 on the bench, almost no vital signs. Only things: Power button white LED flashes several times when USB-PD gets connected (number of flashes varies from three up to twelve times, sometimes no reaction at all). Battery charge indicator LED stays orange. Most interesting is hissing / whining sound from Battery Charge Controller IC BQ25710 on the keyboard side of the main pcb. Board fuses tested and intact, no shorts found so far. BQ25710 is also the only thing on the board to become warm in thermal image (below 70 °C). Thanks for any hint. -
Repaired a customers computer, had a faulty APL 1097 chip and replaced, all well, not shorted anymore, however I am finally getting 12.28Volts on PPBUS_AON, however it stays at 12.28 and doesn't increase to the normal 12.60 Volts. I read that this is the cause
- If the voltage is approximately 12.28-12.35V, it may indicate a communication issue between the SOC and PMICs, or corrupt firmware.
-
Looking to start servicing power tools. I’m looking for isolation transformers for 415/230/110V either separately or combined/tapped, above 5KVA. I’m based in the UK. Any suggestions on where I can source?
Comment