AcBel API0PO13 does not power on. Fan spins a bit then stops.

[sententia]

Hello,

I have this AcBel PSU which is not a usual ATX supply. It does have a 24v rail and two connectors which go to the motherboard (the supply comes from a wincor pos).

As i mentioned the fan when i try to power it on spins for a bit then stops. I went forward and replaced all the capacitor allthough they did not have any visible signs of wear but that didn't help. I haven't replaced the last two 2200uf 6.3v near the output cables as i doubt that it is the problem. Unfortunatly a cheap ESR meter i bought still hasn't arrived so i can't really test the capacitors i removed.

I have no clue at all where to start looking to find the problem.

Allthough the connector have 3 green cables, only 1 seems to try to power it on. I checked the 12v rail with a multimeter and when the PSU tries to start the volt goes up to 8 - 9 v.

Any help is greatly appreciated.

P.S. this is THE HARDEST pcb to desolder i ever encountered!

[Escort Eagle]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Your problem is in the Output . In the Output side you have Three Diode Brackets . One of the three Diode Bracket is Open . Check them carefully . Specially - Red Wire (+5V) Diode Bracket or Orange Wire (+3.3V) Diode Bracket is OPEN . I have shown in the Image .

[kaboom]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Hello,

I have this AcBel PSU which is not a usual ATX supply. It does have a 24v rail and two connectors which go to the motherboard (the supply comes from a wincor pos).

As i mentioned the fan when i try to power it on spins for a bit then stops. I went forward and replaced all the capacitor allthough they did not have any visible signs of wear but that didn't help. I haven't replaced the last two 2200uf 6.3v near the output cables as i doubt that it is the problem. Unfortunatly a cheap ESR meter i bought still hasn't arrived so i can't really test the capacitors i removed.

I have no clue at all where to start looking to find the problem.

Allthough the connector have 3 green cables, only 1 seems to try to power it on. I checked the 12v rail with a multimeter and when the PSU tries to start the volt goes up to 8 - 9 v.

Any help is greatly appreciated.

P.S. this is THE HARDEST pcb to desolder i ever encountered!

Any of the rails shorted to common? Shorted rectifiers and high-ESR/leaky caps likely.

[sententia]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Your problem is in the Output . In the Output side you have Three Diode Brackets . One of the three Diode Bracket is Open . Check them carefully . Specially - Red Wire (+5V) Diode Bracket or Orange Wire (+3.3V) Diode Bracket is OPEN . I have shown in the Image .

Thank you for the detailed info. Is there any way to test these on board? i know they are diodes so i suppose there isn't. I managed to desolder just one of the big ones and it measures ok.

I know my iron tip is not very good for the job but is my 30w iron inadaquate?

Are you positive it should be those that connect (middle pin) to 3.3v and 5v?

[sententia]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Any of the rails shorted to common? Shorted rectifiers and high-ESR/leaky caps likely.

Not really. There is resistance between all rails but no one looks shorted.
As i mentioned in my first post the caps have been replaced with new ones (except 2x 6.3v) which i doubt they are causing the problem.

[Escort Eagle]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Is there any way to test these on board?

Then You have to Desolder the Output Discharging Resistors in every rail . But best way is to check them by desoldering from the PCB .

I know my iron tip is not very good for the job but is my 30w iron inadaquate?

You can use 60W Iron . With 30W iron it is difficult to desolder a dry joint . You can use this tip - Firstly you can give some soldering Lead to the dry joint and then try to desolder that dry joint .

Are you positive it should be those that connect (middle pin) to 3.3v and 5v?

Ya, Normally Middle Pin connects to the +12V, +5V and +3.3V rail if they use 3 diode brackets . Sometimes they use a mosfet in +3.3V rail .

Big Diode is used for +5V rail . Your +12V Diode is OK, because your Fan is spinning . Then rest +3.3V rail's Diode or Mosfet is Open .

I have just repaired a PSU which has same problem as you have . It's +5V Diode was Open .

[Behemot]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Check all the rails, -5 V an -12 V may go bad as well though it's uncommon.

[sententia]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Then You have to Desolder the Output Discharging Resistors in every rail . But best way is to check them by desoldering from the PCB .


You can use 60W Iron . With 30W iron it is difficult to desolder a dry joint . You can use this tip - Firstly you can give some soldering Lead to the dry joint and then try to desolder that dry joint .


Ya, Normally Middle Pin connects to the +12V, +5V and +3.3V rail if they use 3 diode brackets . Sometimes they use a mosfet in +3.3V rail .

Big Diode is used for +5V rail . Your +12V Diode is OK, because your Fan is spinning . Then rest +3.3V rail's Diode or Mosfet is Open .

I have just repaired a PSU which has same problem as you have . It's +5V Diode was Open .

Hello,

I bought a chisel tip for my old weller 50w iron so now no problem with desoldering. I managed to desolder all diodes bridges and heatsink.

Unfortunatly all four of them were tested and are OK. So no problem there.

There are a couple of normal diodes near the output cables, do you think i should test those too?

Any other suggestions as to where the problem might be are greatly appreciated!

[sententia]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Check all the rails, -5 V an -12 V may go bad as well though it's uncommon.

If you mean i should check the switchmode rectifier diodes they tested working.

[sententia]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

I have to mention that this PSU offers a 24v rail. I know for sure that one 24v output is at the other side of the PSU where it connects to mains. I am do not know if it has a 24v output on the internal connectors if that helps in anything.

There are also two big to-264 (i am correct) packages mounted on the other heatsink which i cannot see what they are. I think that these would be, as they are placed on the primary side, power fets.

[Behemot]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

May just be potential between -12 and +12 V.

[sententia]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

May just be potential between -12 and +12 V.

The 24v rail outputs 2A and the -12 only 0.2A. Is it possible to get that amps from +12v and -12v rails?

[Behemot]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Well maybe that's the reason why it's only 0,2 A - quite low for such old design so the power is maybe allocated elsewhere. How much can the regulator handle? If that's like 2,5+ A, that would make sense.

[Escort Eagle]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Woops !!! Output Diodes are OK !! Oh dude ! Then definitely this PSU is going to crack your brain !! Now you have to search the whole PSU (Primary + Secondary) alone, I cann't help you further, because I have not faced so deep problem before .

At last I want to say one thing - Each rail has connection with controller IC for the sense of their presence and measuring them . Follow those lines which are gone to controller IC from each rail (+3.3V to -12V) and check the continuity of those lines and measure resistors or diodes in those lines for checking they are good or not .

Best of Luck dude .

[sententia]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Sooo.... Anyone any guidance as to where to start looking again?

I found that i had another identical failed PSU (just different revision) that doen't have a blown fuse but everything measures 0v on the output. I imagine that the problem may reside on the primary side, and it might be easier to pinpoint the problem. Should i start a new thread for that? ... This does not try to start. It really look dead/silent...

[ben7]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

There are also two big to-264 (i am correct) packages mounted on the other heatsink which i cannot see what they are. I think that these would be, as they are placed on the primary side, power fets.

Correct! They are power transistors, most likely MOSFETs.
Could you take them out and test them? See if they have any shorts.

Does this PSU have a standby voltage also?

Did you get the PSU broken, or did you just find it? Some don't run without some load on the output, this *could* be the problem.

About the other PSU ... I don't know, if you do start another thread, make sure it is titled "Another AcBel API0PO13 - different problem" or something like that, so mods won't mistaken that as a double thread. (Some people post multiple threads for the same problem - that isn't allowed on here as far as I know)

Cheers,
-Ben

[Escort Eagle]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Ya, It is better to start a new thread for new PSU .

[sententia]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Both PSU i have come from same machine. I have it and i tried to test them on the original equipment. So it sould not be a load problem.

Yes they do have standby cable. The first one (that this thread refers to) has normal +5v on the green cable and "tries" to start when it is shorted to ground. The other one is just dead.... 0v

[sententia]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Thanks for the input...

If any of the power fets was shorted, the fuse should blow if i am correct...

Do you think that i should desolder them and test them?

Correct! They are power transistors, most likely MOSFETs.
Could you take them out and test them? See if they have any shorts.

Does this PSU have a standby voltage also?

Did you get the PSU broken, or did you just find it? Some don't run without some load on the output, this *could* be the problem.

About the other PSU ... I don't know, if you do start another thread, make sure it is titled "Another AcBel API0PO13 - different problem" or something like that, so mods won't mistaken that as a double thread. (Some people post multiple threads for the same problem - that isn't allowed on here as far as I know)

Cheers,
-Ben

[Toasty]

Re: AcBel API0PO13 does not power on. Fan spins a bit then stops.

Do you have the 5vsb?

What is the voltage rating of the mains cap?

What voltage do you have across the mains cap at:

1) Standby?

2) On?

T