Re: iMac G5 AcBel 17" API3PC94-290 no voltages
Ok, send it.
Ok, send it.
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veritas odium parit -
Re: iMac G5 AcBel 17" API3PC94-290 no voltages
Hello I know this is an old post but Just wondering if you have any result on this model I have the same model same problem. replaced caps with new but still LED 1 on my mac goes off for a split second and no 24v at all. Could you please let me and others know what happened with your PSU? ThanksComment
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Re: iMac G5 AcBel 17" API3PC94-290 no voltages
If the 24v is down (19-20v in standby), that means the standby section is also down. You are probably missing 5vsb also, yes?
Flip it over and look at Q1 to see if it's burnt. Also, check the output of the TOPSwitch (TOP244Y).
Remember that you are working on the HOT / LINE side of the PSU. The use of an isolation transformer is highly recommended.
Please update your profile to show where you are from. Thanks!
Tveritas odium paritComment
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Re: iMac G5 AcBel 17" API3PC94-290 no voltages
Thanks for quick response, I checked Q1, visual check on that shows no sign of burning out. I checked BCE: no voltage!! I checked TOP244Y MOSFET. Drain is good. it was plugged for just a minute for this test. I checked Source and Drain put my voltmeter on 600 DC and it was showing about 330! BTW I am not that expert but not a newbie - just thought I should mention this
at this point I disconnected the power and touched the copper heatsink attached to TOP244Y. It was HOT. I feel like it should not be that HOT specially when there is no load on PSU. This is as far as I noticed. Any recommendation to what to do next or maybe anything I didn't properly checked??
Last edited by safainla; 05-12-2013, 02:49 AM.Comment
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Re: iMac G5 AcBel 17" API3PC94-290 no voltages
Sounds like the 24v regulator, M6, is bad. It's a KA78M24 mounted on the large heatsink near C66 (1000@35). T2 provides both 5vsb & 24vsb and is driven by the TOP244Y.
You can either lift one leg of the diode that rectifies the 24v, or unbolt and remove M6 to see if 5vsb comes back. The TOP should also be significantly cooler after doing so.
Note that your ground changes from the HOT side (T2 input) to the COLD side (T2 output). There is no common to both.
Tveritas odium paritComment
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Re: iMac G5 AcBel 17" API3PC94-290 no voltages
Thank you for helping me firstly. secondly, I took M6 out it checked the legs on the board without M6 presence it has 32 volt between input and output. (it was not showing anything last time I checked when M6 was in place. Also when I checked with my mutimeter in diod testing mode, M6 shows 42 ohm between input and output BOTH WAYS (switched plus and minus probes) versus a good KA78M15 I had here handy (i know the rating is different and I am not going to use this for my board!) that shows current only in one direction doing the same test above on it. Do you agree with me that this is the problem? I am going to find out where I can find a replacement for M6 and replace it if you confirm. Thanks again.Comment
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Re: iMac G5 AcBel 17" API3PC94-290 no voltages
OK , I got the 24v regulator from local shop and replaced it. Job is done. Thanks again for your help.
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Hello.
Have this 27" iMac, that suddently after 2/3 yearsin storage wont start. when i connect power i was hearing some electric sparks sound from back of PSU. i wigle whole mac and it start with chore. so i remove PSU to check, but there is only AC input and output to board and see no bad connections. i resoldered big chips but nothing changed.
when i measure it outside i found that only 1.3V on SDA/SCL pins. no PS_ON voltage or other voltages
what can i measure to have better understanding where is problem?
anybody know what voltages should be...08-18-2023, 10:35 AM -
Hi,
Im actually trying to find what is going wrong with my sapphire Pulse RX580 8gb... I purchased it used and supposely dead a year ago and found out (thanks internet) that U1000 (And gate sot23-5) was not giving me the high state to the power management IC NCP8122...
At this time, with no spare parts, i decided to put a 1kohm resistor to create the voltage as commented by a guy named Lorkur on this forum (https://*******/viewtopic.php?f=48&t=122873), you ll need to translate it in english.
and voila ! the gpu worked again and i didn't care much since.... -
Hello guys,
I have a Philips 240B7QPJEB. The monitor seems completely dead.
I opened it and measured the voltages of the powersupply. I found that a mosfet was dead and replaced it.
On the connector, that goes to the TCON board, all voltages 15-19V and 5V are present.
The small connector on the left of the PSU has two cables with 18V and all the other have 0.2V. It connects on this small connector on the left ontop of the panel. I guess the backlight? Seens fine I guess.
The weird thing is, that the Power LED is powered over the TCON board.
On The TCON...12-28-2024, 02:12 PM -
Hi chaps.
Having recently picking up two dead 2008 iMacs, one is now working, however there is still one to repair.
I was told that they both had failed power supplies, and seeing how I intend to crack SMPS repairs, it was a challenge not to ignored.
Anyway, this PSU in question had already had someone having a pop at soldering.
The current problem is (at the very least) in the primary side.
Fuse is ok
MOV is ok
NTC is ok
Bridge rectifier is ok (~380vDC)
Fat filter cap is ok
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Hi there I just got some Cooler Master mpx-7001-acabw-eu PSU. There is sticker on it so it is not been open ever.
It have some power good problem, all voltages seems to be ok, but that PG is 0 and blinking on this simple PSU tester, also when on this tester a PSU let out some strange sound inside it ( I can't record it since PSU tester is whistle and covering that sound from PSU ).
When I try to connect a green and black wire on 24 pin connector a fan on PSU just little move and nothing.
Here is a video of problem : https://www.youtube.com/watch?v=3cmO8x05...
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