i9900 Won't Power On - PSU or Logic Board?

[muzicman82]

Alright, so it was time to disassemble and clean my rollers and such. This is not the first time I have done this.

After I was done, I reassembled. I triple checked that all connections were in the right place, etc. I plugged in the USB cord first. Then the AC cable. I head the Windows sound indicating I plugged something in, and then I lost power to the printer. Now it won't turn on at all.

I'm trying to figure out if the PSU is dead. I can see the voltage pin assignments on the bottom of the PSU. I took a multimeter to it and tested for some. I get +3.3V for the logic board. None of the other pins give me the correct reading. Pins 4 & 5 give me 10.6V across GND. I'm assuming these are all DC.

The pinout is as follows:

1. +27V
2. +27V
3. GND
4. +20V
5. +20V
6. GND
7. GND
8. +20VENB
9. +27VCONT
10. +3.3V


Can someone with an i9900 check theirs to see if I should be seeing the above with my meter? I don't want to order a $60 PSU if it isn't going to fix it. I just got new inks, blanks, and 2 new printheads!

 

[Ron350]

muzicman82
Have you found the problem yet?
If not look for a loose connection, broken wire or cracked solder joint, in power supply pin # 8 circuit.

Your power supply stand-by voltages sound good.

Pins 4 &5 @ 10.6
Pin 10 @ 3.3

Maybe my post will motivate one of the electrical engineers on this forum to chime in. I am just a lowly tech that repairs circuit boards not design them.

 

[muzicman82]

Well, how do I get the supply to give me readings for the +27 and +20V, or I guess bring it out of standby?

 

[Ron350]

You can pull the top back off the printer and see that you have the 10.6 and the 3.3 at the main circuit board. Also make sure you have 3.3 volts at one pin on the power button. Check for solder cracks where the power supply wires connect to the main board.

That power supply should have 2 output fuses that might have opened or other bad components.

 

[muzicman82]

I checked everything I am getting at the logic board and the connectors and solder joints are good. I wonder if someone would kindly test their suppy and see if they get something different.

 

[atlascopy]

You should post this problem here:
http://www.fixyourownprinter.com/forums

There are a lot of knowledgeable printer repair technicians that can help you out.