Vestel 17IPS61-3 power board with no output (fried primary)

[Dannyx]

Good day folks. Typical Vestel power supply problem here: someone left their TV plugged in during a power outage and when it came back it fried the power supply of this TV. The board is a 17IPS61-3. The primary was completely destroyed: there were many many blown things on it and I changed what I believe to be everything (thermistor, MOSFET IC, bridge rectifier, couple of SMD resistors, fuse (duuh)) but it still has no output AT ALL. It doesn't blow anything, but it just sits there doing nothing.
I even found the schematic, which was VERY handy, but the secondary side is not exactly the same thing - I found some things which vary between my board and the circuit in the schematic. The weirdest part is the STBY pin (pin9 in the schematic): mine doesn't appear to be connected to anything ! It's connected to a trace which has solder pads on it, but no other components, so WTH ? How does this thing work ? Does it run straight off the 12v rail which is always on ? It could be a different revision or model number. The main board is a 17MB82-2 if it matters. The diodes in the secondary are notorious for going bad, but these ones seem OK. I definitely think I'm not getting any drive from the primary.
Another thing I've noticed: I'm getting 325V on the main capacitor, but the VCC pin of the MOSFET IC seems very unstable: it jumps around 10,15,22V, etc and never seems to stabilize.... I attached the schematic to make it easier for you guys to suggest what to check. Could it be a bad optocoupler ? The diode and resistor that are connected to it were destroyed, so maybe they took out the opto with them ? :| ReeceyBurger123 made a video once which shows how a bad optocoupler shuts down the whole board and the TV has no standby - haven't tried freezing mine yet though. Cheers.

[dick_barton]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

What is the voltage on the ICE chip between VCC and Gound (Pins 7 & 8). The minimum / maximum operating voltage is 10.5 to 25V and is it steady.?

If the mosfet IC you mention above is the ICE3BR1765J then I would check R14/R15/D5 and especially D7.

It is also possible that the opto (U1) has been damaged if the components connected to it were damaged but you should be able to test between pins 1 & 2 with your meter in diode mode. You can also check for a short or low resistance between pins 3 & 4. Also what voltage is across pins 3 & 4 when the power supply is on.

[Dannyx]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

You did not read the latter part of my post too carefully, did you ? The VCC pin of the MOSFET IC seems very unstable: it jumps around 10,11,15V, etc and never seems to stabilize. All diodes check OK. D7 and R14 are missing from my board (no - they weren't blown clear off, as the pads are too intact). I attached a photo of my board - sloppy job on the right there, I know, but the guy I sent to pick up the components brought back SMDs which were one size too big, so I just said F-it. Same for that zener next to it. D15 is a 10ohm resistor and it's OK. C19 and C20 seemed a bit brown and the solder joints looked like they became quite hot and melted, so could it be because of that as well ? Also, I get nothing when I measure the optoisolator (acutally, I do get something around 200mV) and measuring it with my meter's diode function shows 0.397 when forward-biased and 0.391 when reveresed, but it could be because of the circuit...will have to pull out the opto to check for sure. Should it indeed be bad, can I just replace it with another one, say from a Samsung board that I have on hand as long as I put it in the right orientation ? (the same way FETs will always go G-D-S from left to right, even if their specs are different). Or do optos have pinouts that vary drastically ?

[CapLeaker]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

One thing is always very easily overlooked. When the MOSFET blows, it may have destroyed the gate drive circuit of the FET and going further backwards, it may have destroyed the PWM too. Therefore the PSU just sits there and does nothing.

I replaced optos before too, yes, but that is a very rare occurrence. I replaced more bad PWMs, even with the gate drive circuit and the mosfet fully intact.

However, when I had a look at the schematic, there is no Mosfet. So make sure the VC to VCC parts are good, replace the CoolSET PWM and fire it up.

BTW... We do like hi quality, straight shot pictures of the full board. Gives us something to look at and speeds things up a lot.

[ReeceyBurger123]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

Been waiting for the day for one of these IPS61's to go bang ! Agree with CL, luckily the mosfet and controller are in one package meaning you can just change that and respective resistors and the bridge diodes. I would also advise you check C28 for short circuit after removing the mosfet package.

[Dannyx]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

One thing is always very easily overlooked. When the MOSFET blows, it may have destroyed the gate drive circuit of the FET and going further backwards, it may have destroyed the PWM too. Therefore the PSU just sits there and does nothing.

I replaced optos before too, yes, but that is a very rare occurrence. I replaced more bad PWMs, even with the gate drive circuit and the mosfet fully intact.

However, when I had a look at the schematic, there is no Mosfet. So make sure the VC to VCC parts are good, replace the CoolSET PWM and fire it up.

BTW... We do like hi quality, straight shot pictures of the full board. Gives us something to look at and speeds things up a lot.

It turns out it was the optocoupler after all - replaced it and it fired up. I know about the MOSFET jazz, but this one, as you pointed out, has that IC instead of a FET. I posted the close-up because I thought the area was too small to see...no macro lens here, so we make do with what we have )

[dick_barton]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

I guessed that was the chip you meant but wasn't 100% sure.
If you lift out the ICExxxx chip is the Vcc supply at the IC pad of ICExxxx stable?


Edit
So you've found your fault. Well done.

[Dannyx]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

I guessed that was the chip you meant but wasn't 100% sure.
If you lift out the ICExxxx chip is the Vcc supply at the IC pad of ICExxxx stable?


Edit
So you've found your fault. Well done.

Yeah...seems to be working fine (for now at least) ) So I hope this helped someone else out there: if your 17IPS61 is not blowing the fuse but doesn't have any power (including standby), check your optocoupler as well - it might be faulty. Cheers and thanks for the support.

[ReeceyBurger123]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

Nice work

[CapLeaker]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

perfect!

[dinos]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

HELLO. Μy problem is it not loading the main capacitor. You have some answer to this theme. Thank you.

[Dannyx]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

HELLO. Μy problem is it not loading the main capacitor. You have some answer to this theme. Thank you.

Sounds like no power is coming into your board at all. Is the fuse OK ? I can't remember the board by heart after so much time and after fixing so many different things, so some pictures might be handy.

[dinos]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

My fuse is ok. I check everything diode-capacitors-resistors from both sides and evrything it's ok. This is happend from thunder and burn ic ICE3BR1765J. I replace the ic and some parts to burn and I measured them with multimeter. All it's ok. But i don't have power. What else to do. https://www.08elec.fr/1366-thickbox/...3-23204122.jpg.

[senndogg]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

What do you mean by main capacitor? the 400V big one? If there is no voltage here you should also check the 4 diodes and why not, change them.

[dick_barton]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

So what voltages do you have?
It's better to have photo's of your circuit board top and bottom added as attachments.

[Dannyx]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

My fuse is ok. I check everything diode-capacitors-resistors from both sides and evrything it's ok. This is happend from thunder and burn ic ICE3BR1765J. I replace the ic and some parts to burn and I measured them with multimeter. All it's ok. But i don't have power. What else to do. https://www.08elec.fr/1366-thickbox/...3-23204122.jpg.

Well, my thread describes how I got no power because the optocoupler was faulty even when the rest of the components checked out OK, so perhaps yours is too, especially since the issue seems to be almost identical. I'm interested in the main electrolytic cap - should be reading around 320v.

[dick_barton]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

It will be interesting to see if this is a stock fault.

[CapLeaker]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

Check that AC actually goes to the rectifier. A little while ago I had a TV here that went out after a thunder storm. Had no power on the main filter cap. So I've checked the AC input of the rectifier, no power there. So I traced it back and found that the filter inductor at the AC input of the PSU was blown open. Replaced the filter inductor and all was well.

[dinos]

Re: Vestel 17IPS61-3 power board with no output (fried primary)

I will do the measurements you have told me and I will answer you directly. Thank you all for the interest.I try to post photos