Author Topic: ATX Power Supply Dead  (Read 24722 times)

0 Members and 1 Guest are viewing this topic.

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #25 on: March 22, 2017, 06:11:21 pm »
PFC IC Controller
(CM6800TX): "The CM6800 is a controller for power factor corrected switched mode power supplers."

Working on rudimentary schematics now.

Datasheet: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwiimMbz2urSAhVK2GMKHUS5D2oQFggfMAA&url=http%3A%2F%2Fwww.champion-micro.com%2Fdatasheet%2FAnalog%2520Device%2FCM6800.pdf&usg=AFQjCNG0hlXFKyG8nqJ015hesi3hfDp6KA&sig2=nxxLSTTSYGhoIpgRVY0iBA&cad=rja

Click for full size:
« Last Edit: March 22, 2017, 06:17:27 pm by OpenCircuit »
 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #26 on: March 22, 2017, 07:46:10 pm »
Did a bit of tracing today trying to focus on the PFC and IC hoping to figure out the circuitry. Maybe, I should just call Corsair and ask. Some of the symbols were too complex, so I just made a note or a small pic when I didn't know what the "thing" is/was.

I was able to score one more identical broken power supply and one more very similar broken PSU from the same manufacturer! Should be a very inexpensive lesson in microelectronics.

Will catch up on responses later today I hope. Click image below then click it again when it takes you to the new page to really zoom in close.



« Last Edit: March 22, 2017, 08:22:24 pm by OpenCircuit »
 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #27 on: March 22, 2017, 08:09:30 pm »
Does the 25v Cap look burned?:




Other Side of PFC Board:




Will start tracing at the optocouplers next time.

« Last Edit: March 22, 2017, 08:18:34 pm by OpenCircuit »
 
The following users thanked this post: evb149

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #28 on: March 23, 2017, 12:08:15 am »
The color is like ink that runs across onto the PFC controller next to it on the left-just noticed in the photo. Was sure hoping I could find a problem somewhere obvious, replacing that PFC controller does not look like fun. Getting my hand pump on there does not want to extract the solder with the tight pin configuration. Oh well that is in the future.



Ordered cap tester a few days ago....going to be a long wait.
« Last Edit: March 23, 2017, 12:47:30 am by OpenCircuit »
 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #29 on: March 23, 2017, 02:35:36 am »
I would assume it more likely that some issue that will not involve replacing the PFC IC or module would be more likely.
I think the thing to do while the system is apart is to
(a) Inspect it.
(b) trace it to know the most relevant connections
(c) identify / arrange possible points of in-system test access to relevant nodes so you can check the states at run-time
(d) perform any individual component or sub circuit testing that seems possible and necessary.

Otherwise soon I think you should put it back together and then identify the operational voltages at the control and signal nodes that you will have identified so you can determine a cause of why the PFC has no output.

Then, having established the circuit input that may be at fault, look for a way to prove / repair that aspect.


This is music to my ears.

While tracing the opto circuits on the primary side I was thinking about pulling them for a simple bench test in a bread board.....only 4 terminals and I have a few major components already off. Although not sure how sensitive they are to heat.

Really good article on the power supplies explaining PFC. Got a good laugh at a complexity comment on page 3, "Reduced complexity for active PFC...." Circuitry on this board is wow.

I noticed that when you click my thumbnail images posted at postimg.org you can actually download the original in full resolution and zoom in. Excellent website for the larger photos.

« Last Edit: March 23, 2017, 02:46:11 am by OpenCircuit »
 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #30 on: March 23, 2017, 02:40:35 am »
Here is some of the  optocoupler circuitry:

 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #31 on: March 23, 2017, 02:54:47 am »
I originally thought this "chip" had some burn, but not so sure now. Wanted to post to get other opinion(s).

 


Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #33 on: March 23, 2017, 03:25:40 am »
Boost diode ^^^ tests good "854" with negative probe to terminal 1 and "1" with negative probe to terminal 2-red always on other terminal.
 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #34 on: March 23, 2017, 04:08:48 am »

Corsair CX500 PSU Repair - YouTube

Interesting fix for sure; very informative, especially for that PS229 chip. He did have power on all of the rails, where I had nothing. I can sure see something like that as one possibility with mine.

I wonder if that PS229 will fail prematurely since he had to increase the voltage through the pin to get a "signal" across to the other side....?
« Last Edit: March 23, 2017, 05:37:25 am by OpenCircuit »
 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #35 on: March 24, 2017, 12:45:24 am »
Fuse is/was a ceramic 250v 12A; "LF.T12AH250VP"

Is it slow-burn or fast?
 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #36 on: March 24, 2017, 01:19:37 am »
Running out of steam. Eliminating all the small resistors now and trying to get just the main things like transistors, optos, transformers, caps, and output circuits to that sub-board. It appears the main board is supplying +12v+ to that board off to the side which then supplies +5v and +3.3v to peripherals.

*Some peripherals still receive +12v directly from the main board.

 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #37 on: March 24, 2017, 01:21:56 am »
The second PSU with the same model number arrived, but it is from 2011 and the board is way different.
 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #38 on: March 24, 2017, 04:41:30 am »
Here is the board off to the side:


 

Offline OpenCircuitTopic starter

  • Regular Contributor
  • *
  • Posts: 163
  • Country: us
Re: ATX Power Supply Dead
« Reply #39 on: March 24, 2017, 05:29:18 am »
So the "T" in "F.T12AH250VP" stands for time-delay/slow-blow.

Good link on the matter: http://www.instructables.com/id/How-To-Identify-And-Replace-A-Blown-Fuse-1/
« Last Edit: March 24, 2017, 05:34:43 am by OpenCircuit »
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf