HP P2015dn Laser Printer SMPS repair (with Pics)

[SchrodingersCat]

Hey Folks,

One day my HP P2015dn laser printer decided not to power up. No LCD would light up, no motors would turn, no response whatsoever. I didnt the standard stuff, check cables, fuses, etc. with no luck. I could find a service manual for the printer, but could not get a circuit diagram for the circuit board. Guessing it was the PSU SMPS part of the mainboard that was gone, I dismantled the device and took out the mainboard. Both fuses on the board were fine, and there were no signs of any components overheating. So I checked the diodes with a multimeter, all were fine, checked the large capacitor, it also seemed to be fine. So I set to work on analysing the semiconductors.

Now, this is where it gets tricky. I couldnt find any info on the two large transistor looking parts (im guessing they could be transistors/mosfets/triacs?) from their part number. They both have the codes:

7N093
K4005
.01

and

SK
TME87
79

Written on them, but google seems to show up nothing. I will attach pics of the devices. Does anybody know how I could get a spec sheet for the devices so that I can test them, and find out a similiar spec device to replace them if needed?
Does anybody have any other suggestions on how I could diagnose the problem with the PSU?



(P.S, I can probably get a oscilliscope, signal generator, or make an ESR tester, to test out the various components if ye think i need to
Please ignore the lack of second fuse and two diodes in the pic, I was replacing them when I took the pic)

[Ken256]

Re: HP P2015dn Laser Printer SMPS repair (with Pics)

The K4006 is abbreviated for 2SK4006, a Japanese transistor designation. Fuji Electric N-Channel mosfet: http://www.datasheetdir.com/2SK4006-01L+download

The other one is more difficult. I figured out the manufacturer from the logo. Its Sanken. See http://www.advanced-tech.com/ic_logos/ic_logos.htm. Sanken seems to use the TM prefix for triacs. What is the circuit board location for this part? Like Q=transistor D=diode, etc.

Take a picture of the bottom side of the circuit board. I bet the controllers are surface mounted to the bottom. Getting datasheets for the controllers and ICs can be very helpful. You can get an idea of the type of circuit and what the expected signals should be.

[Khron]

Re: HP P2015dn Laser Printer SMPS repair (with Pics)

Here's the datasheet for 2SK4005.

Also, in the 4th photo, i think i can see a "Q1" next to that Sanken triac (you can see the Nais relay in the first photo with the macro of the triac).

But, like Ken256 said, an underside photo could reveal a few (more) things...

[Quasar]

Re: HP P2015dn Laser Printer SMPS repair (with Pics)

Some of these have safety interlocks. Some are 110v lines, others are low voltage to ensure doors etc are closed before printer engages. Make sure your safety switches are in good order.

Trace the input (assume 110v) from each pin at those white connectors (lower left) into the circuit. Very odd for a MOSFET to fail and not cause something to blow. Diodes checked good, so see if you have voltage there with power applied. You should at least get a standby voltage somewhere on that board.

If your getting nothing, check the power cord & outlet. Follow that other white socket in the machine to see where it leads. Could be a breaker inside you are unaware of. The fuser may run through a main breaker and if it opens, shuts the whole thing down.

Lay it out and draw it out.