Sanyo DP42545

[thumper69]

We will start with this question. This tv clicks but does not start-up. shuts down after about 4 sec. There is no voltage at vset.

[budm]

Re: Sanyo DP42545

You will get a lot more help by at least up load good clear pictures of the whole backside of the TV showing all the boards and pictures of the whole board of each board.

[thumper69]

Re: Sanyo DP42545

Pictures of tv.

[thumper69]

Re: Sanyo DP42545

Can anyone tell me if the vset voltage is generated from the power supply.

[MagicSmoke]

Re: Sanyo DP42545

Which board is Vset test point on, and is there a Vset adjustment pot on power board?

[thumper69]

Re: Sanyo DP42545

Vset is on main power board and feeds VS yes there is an adjustment for that on main.

[thumper69]

Re: Sanyo DP42545

Vset is also listed on VS board.

[will62]

Re: Sanyo DP42545

Here is the vset trim pot. Also, are you getting a ps_on signal from the main?

edit: re-read your post, see you found the adjustment pot.

[thumper69]

Re: Sanyo DP42545

The following is a list of Measured voltages.
Va= 70.3
Vsc= -198
Vs= 210
Ve= 82
Vset= -198 than goes away sticker says +198 led on board flashes 6 times Vset?
stby= 5.18
pson board says (vs on) 0 plugged in rises to 3.26 when on-off switch pressed

[will62]

Re: Sanyo DP42545

I'm adding a diagram that may help you troubleshoot the Vset voltage.

[thumper69]

Re: Sanyo DP42545

What kind of load for testing purposes could i use.

[thumper69]

Re: Sanyo DP42545

I had changed the power supply board and it seems unlikely the replacement board would have the same problem, but it does give the same symptoms. Perhaps a dummy load would prove that out if possible.

[will62]

Re: Sanyo DP42545

Not sure what you could use to load test the Vset line. I believe it is only rated to 50mA, so that would be a little less than 10 watts. If you have already replaced the power board, I would move on to the Y-main board and trace the Vset circuit there.

You said that when you first apply power, Vset reads -198V, then goes to 0. That -198V is the Vscan voltage. Maybe you could check the resistance from Vset to Vscan with cn8003 connected and disconnected. Try the same for Vset to ground.

[thumper69]

Re: Sanyo DP42545

Thank You for your help thus far. Will check the resistance and see where that leads.

[thumper69]

Re: Sanyo DP42545

Update on DP42545. A friend of mine has the exact same tv only working, and i was able to sub some boards to determine where my issue was. Well it did turn out to be the power supply board. The bad part is i find no one that has this board available. The parts suggested to check could not be in a much worse place to get at. Do you think i can remove these parts with just a soldering iron. Afraid with all the sub components on the underside of board heat gun would be too much, any suggestions. Thanks in advance.

[will62]

Re: Sanyo DP42545

They're all through hole, so should be OK with an iron. Before you remove them, I'd try to get part numbers off them, and look up data sheets to see what you can test in circuit. You may get lucky and find the bad component w/o removing them all. If you look from the top of the board, you'll see that the Vscan and Ve circuits are using the same components (confirm visually). So, you should be able to compare the suspect parts on the Vset circuit with known good parts in the other 2 circuits.