MPC 3500 DEAD! only main powe led on

[kannuki2]

Re: MPC 3500 DEAD! only main powe led on

I hope there is no pinch harness. I would try new laser polygon motor and new bicu.

[iscott]

Re: MPC 3500 DEAD! only main powe led on

If power supply doesn't fix it check the laser. Had developer get in one and short it out.

[rsyarcia]

Re: MPC 3500 DEAD! only main powe led on

Hi guys! I've been trying to bring back to life a couple of power supply boards... The old ones I mean - AZ24-0110. I've got three of those with identical fault: machine dead, blowing FU2.

So I put it on my bench a had a closer look. In all cases - main rectifier shorted, dead as a stick, as well as the diode mentioned before (YG963) and one of the PFC's MosFET transistor 2SK2915. So I did change the components and it's no longer blowing the fuse, however I can't get +24V working.. The only voltage looking good is +5V, but it does have a separate switching power supply circuit. No chance to find a schematic diagram as you all probably know...

Just wondering if there's a way to get +24V up and running on a bench, out of the machine? Doesn't it need some "start" signal from the machine's controller by any chance?

Thanks in advance

Kris

do you want help? i have solved a lot of this problem..i am a hair straightener technician but i know how to fix this.

[ATSBMCO]

Re: MPC 3500 DEAD! only main powe led on

Hello,

I have come across this fault on an old MPC3500; and due to the high cost of replacing the PSU I have been looking at what could be the cause.
I too had a dead rectifier, plus a few items that do not seem right up on inspection around the diode D1 area. Plus resistor R3 cracked under pressure after replacing the rectifier DB1 and trying after power up.

Has anybody repaired this PSU successfully with new components?

Would be interesting to know before I spend to much time on this circuit repair.

Thanks

[Eric1968]

Re: MPC 3500 DEAD! only main powe led on

Hello,

I have come across this fault on an old MPC3500; and due to the high cost of replacing the PSU I have been looking at what could be the cause.
I too had a dead rectifier, plus a few items that do not seem right up on inspection around the diode D1 area. Plus resistor R3 cracked under pressure after replacing the rectifier DB1 and trying after power up.

Has anybody repaired this PSU successfully with new components?

Would be interesting to know before I spend to much time on this circuit repair.

Thanks

This can also be a defective Polygon Mirror Motor. I've had this a few times with the MP C2500/C3500-models. If you disconnect the Polygon Mirror Motor chances are that the display lights up and displays the SC for the Polygon Mirror Motor. Replacing it solved it for me.

[ATSBMCO]

Re: MPC 3500 DEAD! only main powe led on

Hello, and thank you, Eric, for your reply.

This particular machine did indeed blow the power supply unit. A few components have blown and I was wondering has anybody been able to repair the circuit. I appreciate your advice with the polygon motor, and I will have a look at this though.

Did you repair or just replace the power supply on your faulty machine's?

Thanks

[gasior78]

Re: MPC 3500 DEAD! only main powe led on

Hi there, I had a similar problem with several power supplies and as a standard there were always the same components down... At least the ones measurable with a simple multimeter. Rectifier, temp-fused resistors and a pair of Mos-FET's in PFC (power factor correction) section. Usually nothing more. But still it did not fix the problem... 5V was there, no more blown fuses or other components, but 24V still missing.. Hope you're gonna get a bit further than myself...

[glyn545]

Re: MPC 3500 DEAD! only main powe led on

If you can browse into the machine, check if a polygon mirror error is displayed. If it is you need to replace the polygon & possibly also the PSU

Polygon mirror motor and BICU .

[ATSBMCO]

Re: MPC 3500 DEAD! only main powe led on

Thank you Gasior78,

I now have the same 5v line but no 24v present, as what you have. But I was wondering did you try the power supply back in the copier to see if it needed to be connected to activate the 24v, as sometimes PCB's require the circuit to be made throughout to work?

I haven't the machine at our workshop to check this, its still at the customers.
Thanks

[gasior78]

Re: MPC 3500 DEAD! only main powe led on

Yes , I did try with no luck. Moreover - it is confirmed by the person I trust in this matter that 24V should be there even with the board on a desk. No need to put it in the machine. Good luck and please share your further experiences!

[ATSBMCO]

Re: MPC 3500 DEAD! only main powe led on

Hello,

Checking over the PCB again I was measuring 5v present at the pins of the large connectors of CN912, CN910, CN914, CN913, but still no 24v. However, I also noticed that resistor R55 (Next to Q10) was open circuit too. After replacing this resistor the circuit was only showing 5v line on connector CN909 only.

As I thought, the circuit carries the 5v to the keyboard ready for the power to be depressed, it shows that the PCB is required to be installed back into the copier for the entire circuit to activate, once installed it worked.

I can only tell you what I have seen and repaired.
Good luck.

[copier tech]

Re: MPC 3500 DEAD! only main powe led on

Good fix, but most engineers down have time for that!
Order a new PSB, fit it & on to the next moaning customer!!!!

[jhon]

Re: MPC 3500 DEAD! only main powe led on

Good fix, but most engineers down have time for that!
Order a new PSB, fit it & on to the next moaning customer!!!!

what is the power supply section in this image how can i power and test the board.... hoping for your help....