Mitsubishi DLP WD60735

[Dgtech]

Ok so a co-worker brought me this TV today to be repaired. The symptoms are - Blinking orange power LED - no video or sound - just a relay click when plugged in.

I cannot find a service manual for this model.
Here's what I have, all caps and fuses are OK.
I have limited knowledge about DLP power supply requirements. I already notice voltages coming back in from other devices, probably for monitoring...etc. This supply board has a STR-W6734 PWM chip. I think this one is defective but I need verification.

Voltages on STR-W6734'
Pin 1 = 160VDC
Pin 2 = There is no pin 2 for this chip.
Pin 3 = GND
Pin 4 = Vcc 17.7VDC
Pin 5 = 0 VDC
Pin 6 = FB 1.4VDC
Pin 7 = .6 VDC

There is a datasheed for this chip that is generic at best. Has no indication even what VCC should be.
I will post photos after dinner - priorities.

[PlainBill]

Re: Mitsubishi DLP WD60735

Ok so a co-worker brought me this TV today to be repaired. The symptoms are - Blinking orange power LED - no video or sound - just a relay click when plugged in.

I cannot find a service manual for this model.
Here's what I have, all caps and fuses are OK.
I have limited knowledge about DLP power supply requirements. I already notice voltages coming back in from other devices, probably for monitoring...etc. This supply board has a STR-W6734 PWM chip. I think this one is defective but I need verification.

Voltages on STR-W6734'
Pin 1 = 160VDC
Pin 2 = There is no pin 2 for this chip.
Pin 3 = GND
Pin 4 = Vcc 17.7VDC
Pin 5 = 0 VDC
Pin 6 = FB 1.4VDC
Pin 7 = .6 VDC

There is a datasheed for this chip that is generic at best. Has no indication even what VCC should be.
I will post photos after dinner - priorities.

The service manual is available at Elektrotanya.

PlainBill

[Dgtech]

Re: Mitsubishi DLP WD60735

Thanks for the link.
I worked on a unit before that had an STRT-G6153 chip that I found to be bad due to a more simple design.
Any tips on how to test this chip? The voltages are above. I'll try to take a picture of the waveform from my scope tomorrow and post it. I really dont want to suspect this chip cause I can not find one for sale.

[PlainBill]

Re: Mitsubishi DLP WD60735

Thanks for the link.
I worked on a unit before that had an STRT-G6153 chip that I found to be bad due to a more simple design.
Any tips on how to test this chip? The voltages are above. I'll try to take a picture of the waveform from my scope tomorrow and post it. I really dont want to suspect this chip cause I can not find one for sale.

This is a fairly straightforward design, at least compared the a plasma supply. It appears there are only three outputs from the main power transformer - 21 volts for the audio; Vcc for this controller, and 12 volts for the main power supply. If you have them, the chip is working properly.

Of course, using an isolation transformer is mandatory. The waveform at pin 1 would be instructive. Depending on the AC supply, 160 volts is a little low for the rectified AC, but is right in line with what I would expect if the power supply is providing only standby voltage.

PlainBill

[Dgtech]

Re: Mitsubishi DLP WD60735

Well to close this one out, sometimes you have to refer to that old saying (K.I.S.S.).

In my first post on this thread I refered to a blinking orange power LED. The plate in front of the indicator LED's was missing and the wrong assumption was made that this was the Power LED. Instead it was the Lamp LED. In the service manual, (thanks again Plainbill), the slow blinking lamp LED code means the access pannel to the lamp is not secured. With the back off, I located a simple wisker type of micro switch for the door and activated it. After powering the unit up - we have life.

Basically, the switch was not activating due to a misplaced screw from someone else probably switching the lamp cartridge. The switch most likely activated but was close enough to the threshold of not activating and one day switched over. This switch is not on or near the power supply but however is a permissive for getting out of stanby mode in which activates some of the voltages on the power supply board.

[pclaptop]

Re: Mitsubishi DLP WD60735

I will start a new thread but have to make a few posts first. My WD60735 has the BLINKING green light and nothing past that! A google says the caps have gone bad on the PWR board!
So rather than go into more detail here I will start a new thread!

Pclaptop

[pclaptop]

Re: Mitsubishi DLP WD60735

For some reason I still cant start a new thread . . . . but concerning the blinkging green light ONLY problem, when I search google, "WD60735 has blinking green light", EVERY bad cap result/post for this Mitsubishi say change the "7" bad 1000uf caps (to 680uf) on the power board!

There are no 1000uf caps (never the less "7" of them) on the PWR board! I see two 2200uf caps!

If I have committed a major faux pas, could an admin move this to a "new thread" post?

thanks don't mean to be a newbie hemmorhoid!

[failinx@yahoo.com]

Re: Mitsubishi DLP WD60735

Any closure on this. My set is doing the same thing