toshiba 42wlt66 needs help before I throw a hammer at it...!

[djsmasm]

first of all, my apologies if such a problem has already been discussed....!

now the explaination of the thread title!

the first time I plugged the set, relays were continuously clicking in a loop, synced with backlight trying to start....

so I've decided to change 3 ICs in power supply, but because I couldn't buy all of them from the same seller, the third one only arrived today, so I changed both the 2 others before, and it didn't solve anything!

now that I've changed the third, (the one for the PFC, SRX2039) relays don't click anymore but the STRZ 4479 doesn't work anymore either, so at least the inverters are not powered, but voltages produced by STRW6765 are fine........

I do have the service manual but it's almost useless because some of the voltages when everything is working aren't known!

I have 320Vdc instead of 370 on the big 450V capacitor (and thus less than the 5.1V I should have on FB pin of 2039), don't know if problem comes from that.

5V standby is fine, but 25V standby is "only" 22V (with the "new" 2039)

this voltage, when it's 25V, is used to produce 22V which goes to the 4479, but I only have 10V on its VCC pin

I've put back the original 2039, and everything is back to start (25V standby, 22V on 4479 VCC pin and 24V for inverters are back)!

I guess both of the 2039 are faulty, each one in its own way!

inverters have already been changed so I really doubt they're faulty

only once, the set had worked for a few seconds and fortunately, I had it plugged on a power meter, which had displayed 250W so at least that had been right!

to sum up, all voltages (but still with 320 instead of 370V) are fine and relays don't click only when backlight "ON" command is not connected....!

thanks for reading me.....!

and please correct me if my English isn't good enough....lol

[ReeceyBurger123]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

If you know the Psu is the problem why throw it out ? Also maybe wait or Pm budm to help you debug the circuit.

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

If you know the Psu is the problem why throw it out ? Also maybe wait or Pm budm to help you debug the circuit.

the goal is to fix it, but it's really getting me angry to have this problem.....lol

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

can a moderator delete this thread?

nobody will notice it has gone.......

[comptek]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

are you getting BL-On and PS-ON signal off of the mainboard ?

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

are you getting BL-On and PS-ON signal off of the mainboard ?

yes but only when BL-on is disconnected, otherwise power loops endlessly.....lol

the main question here is : is 320V instead of 370 normal......?

I've ordered two other 2039 ICs, but china to france can take a month.......!

[comptek]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

see my post its worth a try

only the green one for now see what happens
im not held responsible if it goes wrong its just a pointer

https://www.badcaps.net/forum/showpo...9&postcount=16

whole post
https://www.badcaps.net/forum/showthread.php?t=50454

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

what do you want me to try, exactly.......? lol!

if only someone with a working set could check the 370V, it would help a lot, but that would also be a miracle....!

[Alastair E]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

If there's only 320 on the reservoir cap--then the PFC isnt working and the set will shut down.

You need to find why the PFC isn't running.

[budwich]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

have you replaced the capacitor or at least checked it? Have you looked at anything with a scope?

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

have you replaced the capacitor or at least checked it? Have you looked at anything with a scope?

it was ok (capacity and ESR) the first time I checked it...

[but I've bought some other capacitors for an amplifier, and although they were supposed to be new, they weren't at all!

I've decided to check them, but one was still charged and it has killed my esr meter.....so I can't check any component until I get the new meter I ordered a few days ago, but as I already said, china is far from france, so it won't arrive soon...]

my scope isn't isolated from mains, so I can't use it.....!

I've just bought a new capacitor from france, that's a miracle!!

should arrive under 3 days...

I'll tell if it has changed something after replacement!

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

If there's only 320 on the reservoir cap--then the PFC isnt working and the set will shut down.

You need to find why the PFC isn't running.

so why is it sort of working while backlight command not connected......?

does it mean the whole power supply circuitry can only work with 370V?

[budwich]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

use your scope to look at the outputs on the "other side" of the transformers (ie. "DC" values that are going to the other boards).

As for your question above... that's because the backlights aren't on and therefore aren't drawing anything which means that a "compromise" switching power supply might still "sort of" work.

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

use your scope to look at the outputs on the "other side" of the transformers (ie. "DC" values that are going to the other boards).

As for your question above... that's because the backlights aren't on and therefore aren't drawing anything which means that a "compromise" switching power supply might still "sort of" work.

I'll firstly change the big capacitor and the 2039 when they are arrived, and I'll get back here once done!

I thank you now, as it can take a while for components to come...!

[budm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

Can we get to see the pictures of the whole back side of the TV and the boards?
Power supply board P/N?
Service manuals:
http://elektrotanya.com/?q=showresul...at2=schematics

See Main power supply SCH PDF attached.

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

Can we get to see the pictures of the whole back side of the TV and the boards?
Power supply board P/N?
Service manuals:
http://elektrotanya.com/?q=showresul...at2=schematics

See Main power supply SCH PDF attached.

I already have the SM, but thanks!

and my mistake, it's WLG instead of WLT, but I couldn't tell the difference.....lol

I've attached a pic of the rear!

[jetadm123]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

While the preference on this forum is to repair boards (especially power supplies) at the component level, I did a quick check on eBay for the PE0063C power supply and it would seem they can be purchased from the UK for a pretty low price. I don't know what the exchange rate is between the UK and France, but this might one of those occasions where replacing the entire board might be a better choice than continually throwing parts (those srx2039's are not cheap!) at it with no guarantee of success.

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

While the preference on this forum is to repair boards (especially power supplies) at the component level, I did a quick check on eBay for the PE0063C power supply and it would seem they can be purchased from the UK for a pretty low price. I don't know what the exchange rate is between the UK and France, but this might one of those occasions where replacing the entire board might be a better choice than continually throwing parts (those srx2039's are not cheap!) at it with no guarantee of success.

- where did you see PE0063C? (the correct ref is PE0071A and may not be as cheap as 0063...?)
- the 2039s I bought are not that expensive (12€ for 2 pcs) but I don't know if they're genuine.....!

TYVM!

[jetadm123]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

Oops! My error. I was looking at the secondary supply (the brown board in your photo).

[djsmasm]

Re: toshiba 42wlt66 needs help before I throw a hammer at it...!

Oops! My error. I was looking at the secondary supply (the brown board in your photo).

yes, that's it! this one should be good, though.....!