Toshiba 19DL502B totally dead

[viera247]

Re: Toshiba 19DL502B totally dead

Re C735 voltage, checked again three times and yes it registers 12.4 V

[budm]

Re: Toshiba 19DL502B totally dead

OK, I traced out the board, all four of the rectifier Diodes are connected in parallel.
Please verify if all the + legs of the all four filter caps are tied together, it should all show <1 Ohm when measured between the plus legs.
C729
C730
C731
C735

[budm]

Re: Toshiba 19DL502B totally dead

BTW, Does your power cord has ground pin?
What resistance do you read on those two blue caps?
What resistance do you read between the two leg of the blue cap C724?

[viera247]

Re: Toshiba 19DL502B totally dead

Sorry budm you have lost me there. Not sure what I should measure. Should I measure resistance between eg C730 + leg and C729 + leg?

There is a huge gap in knowledge here and I do appreciate the expertise that is on offer so apologies if my question sounds ridiculous!

[budm]

Re: Toshiba 19DL502B totally dead

Just measure the resistance between the two legs of the blue disc cap C724 for now.

[budm]

Re: Toshiba 19DL502B totally dead

Y caps connections.

[viera247]

Re: Toshiba 19DL502B totally dead

First can I update on my previous reply to Dick_Barton. My resistance measurements of C711 and C701 were wrong as I was holding the probes against the cap ends. When placed on my desktop with just the ends touching the reading is 1.
Measuring C724 which is still on the board gives the same reading of 1.
Using my cap meter I get 960PF and 920PF respectively for the former and 1020PF for C724.

There is no ground pin on the TV power cord.

I appreciate the willingness to share knowledge on this great forum and hope that it will lead me to having a working TV. It certainly seemed very close when having replaced D708, D709, D712 and D713 the TV powered on. Unfortunately when the PSU fixing screw at PL707 was inserted the TV failed then to power on. Removed the screw and the power light illuminated again!

[budm]

Re: Toshiba 19DL502B totally dead

So those safety caps do not show leakage resistance at the moment using the meter to test.
If you mount the board back in place with all the screws, do you get the DCV on those caps that we were checking?
C729
C730
C731
C735

[viera247]

Re: Toshiba 19DL502B totally dead

Sadly I get nothing other than a clicking sound from the board.

[budm]

Re: Toshiba 19DL502B totally dead

Sadly I get nothing other than a clicking sound from the board.

This is without other boards connected to this power supply board?

[viera247]

Re: Toshiba 19DL502B totally dead

Powered off then removed the screw from only PL707 and plugged back into mains. TV powers on and soon goes in to standby as it should. I checked C731 at this point and the reading shown was 8.5 DCV but immediately the TV powered off and the clicking sound from the PSU could be heard. Now no reading at any of the above caps so powered off again.

[viera247]

Re: Toshiba 19DL502B totally dead

This is without other boards connected to this power supply board?

No the PSU is connected to both the other boards

[budm]

Re: Toshiba 19DL502B totally dead

Try it without other boards connected and all screws are in place, it sounds like something is overload the power supply so it goes into shutdown/start up cycle.

[viera247]

Re: Toshiba 19DL502B totally dead

Try it without other boards connected and all screws are in place, it sounds like something is overload the power supply so it goes into shutdown/start up cycle.

Done that. There is now no connection to the other two boards and the PSU just clicks away!

[budm]

Re: Toshiba 19DL502B totally dead

Something on the board must be shorting to the chassis.
What happen if you do not put the board mounting screw for the PL709, but PL707 in place? Something is not making any sense here.

[viera247]

Re: Toshiba 19DL502B totally dead

Hi Again
With PL709 out and PL707 in the set remains in the non-responsive ticking state. I totally agree that it is puzzling.

The TV has had very little use over the past 4 years being simply used in a spare room for the occasional visitor. It has not been subject to any external damage etc. In fact it has been disconnected for most of its life. Says a lot about the quality of Vestel I guess.

[viera247]

Re: Toshiba 19DL502B totally dead

Hi Again
With PL709 out and PL707 in the set remains in the non-responsive ticking state. I totally agree that it is puzzling.

The TV has had very little use over the past 4 years being simply used in a spare room for the occasional visitor. It has not been subject to any external damage etc. In fact it has been disconnected for most of its life. Says a lot about the quality of Vestel I guess.

Now removed PL707 and slightly slackened the other hree. Switched on the power and we have a functioning unit again. I know that if I add in the screw at PL707 it will go into protect mode!

[budm]

Re: Toshiba 19DL502B totally dead

I am curious at this point, try removing one of the those 4 blue cap one at at a time to see what happen. The meter may not show any leakage resistance of the caps but the cap may break down when AC 230V is applied.

[viera247]

Re: Toshiba 19DL502B totally dead

Latest position having played around with all 4 fixing screws is that when all four are not screwed down tight but still sufficient to hold the board in place and all are in contact with the mounting ring I have a tv that does power up. I am now wondering whether to reassemble tomorrow but hesitant since the shorting issue hasn't been resolved.

[viera247]

Re: Toshiba 19DL502B totally dead

I am curious at this point, try removing one of the those 4 blue cap one at at a time to see what happen. The meter may not show any leakage resistance of the caps but the cap may break down when AC 230V is applied.

I will do this tomorrow and report back

Thanks for staying with this so far!