PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

[xclusiveplayer]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

I just tested some diodes I have lying around in my tool box and those diodes are giving OL in reverse polarity. So in-circuit testing for diode in reverse polarity is inaccurate.

[12ax7a]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

a couple of things here. in photographs, lighting & the lens can play tricks so no way to be sure but i've reposted a couple of your pics with 2 circles of interest.

one has a circle around what appears to be a couple bloated-top caps.

the other has a circle around what appears to be a burnt resistor.

you'll have to check them in person to see if that's real.

(with the power off that is - remember, death is permanent).

[PlainBill]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

a couple of things here. in photographs, lighting & the lens can play tricks so no way to be sure but i've reposted a couple of your pics with 2 circles of interest.

one has a circle around what appears to be a couple bloated-top caps.

the other has a circle around what appears to be a burnt resistor.

you'll have to check them in person to see if that's real.

(with the power off that is - remember, death is permanent).

Good catch, 12AX7A.

By the way, I knew a 12AU7A. Any relation?

PlainBill

[12ax7a]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

yeah, he's my cousin.. but he's only got 20% of what i've got .. ha ha

he has a twin brother, ECC82 .. but i think he lives overseas... ha ha

.. a triode walks into a bar...

ok - i'll stop there...

yeah well, we can see who the tube guys are here...

'unfortunately' it gives our age away a little bit - but really that was part of the joke in using that for a username.. it also tells me who is into guitar amps, radio, hi-fi, etc... i always say there's a reason that tubes are still in use nowadays ... they've yet to really come out with a solid state substitute .. semiconductor junctions are still just way too noisy.. that really does say something about an almost 100 year old technology.. amazing really...

p.s. mr bill, you do some great work on this forum.. i don't know how you find all the time.. i hope some of these guys are sending you gift certificates for dinner or something. best of luck & good health on the upcoming operation - i hope we'll see plenty more of your incredible participation here.

(-:

[xclusiveplayer]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

a couple of things here. in photographs, lighting & the lens can play tricks so no way to be sure but i've reposted a couple of your pics with 2 circles of interest.

one has a circle around what appears to be a couple bloated-top caps.

the other has a circle around what appears to be a burnt resistor.

you'll have to check them in person to see if that's real.

(with the power off that is - remember, death is permanent).

The caps looks perfect in person. Unfortunately I don't own a ESR meter to really be sure.

I was going to mention about that resistor. I just tested all of the resistor under that heat sink and they all are giving 22.00kohm. So I'm assuming they are still good.

This is driving me nuts, I swear for as long as I live I will never buy a Philips TV again.

[12ax7a]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

you might have to unsolder a leg on that resistor to check it.

i'm seeing blue grey grey on those .. not red red orange..

probably something in parallel.

it could also be intermittent.

[PlainBill]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

The caps looks perfect in person. Unfortunately I don't own a ESR meter to really be sure.

I was going to mention about that resistor. I just tested all of the resistor under that heat sink and they all are giving 22.00kohm. So I'm assuming they are still good.

This is driving me nuts, I swear for as long as I live I will never buy a Philips TV again.

A few points for your consideration:

The service manual is available for that TV set; it appears it will cost about $10-$15.

After some studying, I realized the only major cap on the 'live' side is the large one. If it doesn't have voltage on it, that's a problem. The center picture of post#11 in this thread shows the bridge rectifier. If you haven't already done so, check for 120VAC on the two center terminals of the bridge, and about 165 VDC on the two outside terminals.

Something to look for is bad solder joints, especially on the large transformers.

PlainBill

[tmwalsh]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

You said: However, testing them in reverse polarity I'm getting an increasing reading instead of "O.L".

I suspect you are charging up one of the caps... At least that has been my experience when the resistance slowly climbs. It will discharge the battery in the DMM or VOM or DVM or whatever.
To avoid that, where the diodes are individual, you have to unsolder [lift] one of the legs of the diode from the circuit in question, as was noted above somewhere... Then you are testing the diode individually without interference from other components. The display of OL is, I believe, short for OverLoad, or a resistance above the current setting of the meter. Diodes like to conduct in one direction only, that is why they are used to rectify AC current. They don't like to conduct in the opposite direction, thus the higher resistance when the probes are applied as directed. If the ohms are high in both directions, it is 'open', and if the ohms are low in both directions, it is labeled "shorted". Neither condition is optimum for rectifying electric current.
The packages that were referred to, mounted to the heat sinks, are a combination of 4 diodes set up to form a rectifier. AC in on two legs, and DC out on the other two. Internally, the diodes are joined head to tail to form a pair that conducts the 'up' AC current flow and another pair to conduct the 'down' flow, as viewed on a scope. I would test the input for AC and the output for DC. If none were there, I'd remove the rectifier and measure resistance out of circuit, or replace it or both.
tom

[PlainBill]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

yeah, he's my cousin.. but he's only got 20% of what i've got .. ha ha

he has a twin brother, ECC82 .. but i think he lives overseas... ha ha

.. a triode walks into a bar...

ok - i'll stop there...

I first heard it as 'A diode, a triode, and a power pentode walked into a saloon.....'

Good grief, the spell checker in Firefox doesn't recognize 'triode'!!

yeah well, we can see who the tube guys are here...

'unfortunately' it gives our age away a little bit - but really that was part of the joke in using that for a username.. it also tells me who is into guitar amps, radio, hi-fi, etc... i always say there's a reason that tubes are still in use nowadays ... they've yet to really come out with a solid state substitute .. semiconductor junctions are still just way too noisy.. that really does say something about an almost 100 year old technology.. amazing really...

I've mixed feelings about this. Yes, there are things that solid state circuitry still can't duplicate. On the other hand, in most cases, it's really niche applications. As far as the claims made by audiophiles... Well, I'm a skeptic.

p.s. mr bill, you do some great work on this forum.. i don't know how you find all the time..

Well, I'm disabled due to COPD. By my nature (and it's a guy thing), I'm a fixer. For the most part, electronics is easy. And a book with the title of 'Logical Troubleshooting' did a lot.

i hope some of these guys are sending you gift certificates for dinner or something.

Well, someone did send me a Dell monitor - but no base.

best of luck & good health on the upcoming operation - i hope we'll see plenty more of your incredible participation here.
(-:

I hope so too, it keeps me going.

PlainBill

[xclusiveplayer]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

A few points for your consideration:

The service manual is available for that TV set; it appears it will cost about $10-$15.

After some studying, I realized the only major cap on the 'live' side is the large one. If it doesn't have voltage on it, that's a problem. The center picture of post#11 in this thread shows the bridge rectifier. If you haven't already done so, check for 120VAC on the two center terminals of the bridge, and about 165 VDC on the two outside terminals.

Something to look for is bad solder joints, especially on the large transformers.

PlainBill

I tested the large cap multiple times and still get no VDC voltage from it. The smaller ones on the right side are giving the same result.

The bridge rectifier you mentioned is the one labeled GBU606? I measured both the inside and outside of those terminals while plugged in and got nothing.

Are you sure it's not a diode because it's labeled D020?

[Wizard]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

PFC circuit is OFF in standby hence little voltage on this capacitor, hence the confusion.

You have did few checks of standby voltage output? It is either 5V or 12V. Then move on to power on pin that is output from mainboard. Should change voltage when TV is on or off.

Quick check for standby is measure voltage on the IR sensor. It is present all the time.

If standby voltage is there but no change in power on pin, replace mainboard.
If standby is there, and power on voltage changes, replace power supply.

Cheers, Wizard

[xclusiveplayer]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

PFC circuit is OFF in standby hence little voltage on this capacitor, hence the confusion.

You have did few checks of standby voltage output? It is either 5V or 12V. Then move on to power on pin that is output from mainboard. Should change voltage when TV is on or off.

Quick check for standby is measure voltage on the IR sensor. It is present all the time.

If standby voltage is there but no change in power on pin, replace mainboard.
If standby is there, and power on voltage changes, replace power supply.

Cheers, Wizard

To be honest I have no idea how to check the standby voltage. Could you elaborate on this further?

[Wizard]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

Trickle of power to have microcontroller be alive on the mainboard itself while TV is in standby. Hence the term.

Remember, choose which ground to measure. Particularly power supply. If it is on hot side, always use hot side ground (this is isolated and is from negative side of main capacitor and measure hot side voltages. Careful!) Cold side is any ground that is metallic on the chassis also on the power supply's and mainboard's ground plane. You will not get right reading ACROSS hot and cold side.

Keep probing the power supply cold-side outputs till you find any voltage with negative probe on the cold ground of the chassis.

Cheers, Wizard

[PlainBill]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

I tested the large cap multiple times and still get no VDC voltage from it. The smaller ones on the right side are giving the same result.

The bridge rectifier you mentioned is the one labeled GBU606? I measured both the inside and outside of those terminals while plugged in and got nothing.

Are you sure it's not a diode because it's labeled D020?

GBU606 is a bridge rectifier. Depending on where you were educated, where you live, who your boss is, and the day of the week it could be designated D020, BR020, Rect1, or whatever. With the TV plugged in you should see AC voltage across the two center pins. If you don't something is bad on the AC input.

I've marked up the picture of the bottom (good thing you took that) What I would suggest is to check continuity of the entire power input system. Have the power cord plugged into the TV, but NOT the outlet. Set your DMM to the lowest ohms scale. At the top right I've marked the terminals of the bridge rectifier. Counting from the left, terminals 2 and 3 are the AC input.

Hold one probe on terminal 2 of the bridge rectifier. Working down the board, you should get continuity to the top left terminal of L011, the bottom left terminal of L011, the top left terminal of L010, the bottom left terminal of L010, the left terminal of the AC input connector, and finally, to one of the two blades of the power cord. If at any point you lose continuity, you have located a problem. Pay special attention to the solder on the pins of L010 and L011.

If you got continuity all the way out to the power cord, start by putting one probe on pin 3 of the bridge rectifier, and working your down the right hand side through the NTC, the right terminals of L011, the right terminals of L010, the terminals of the fuse, and finally the AC connector and the power cord.

PlainBill

[xclusiveplayer]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

Hold one probe on terminal 2 of the bridge rectifier. Working down the board, you should get continuity to the top left terminal of L011, the bottom left terminal of L011, the top left terminal of L010, the bottom left terminal of L010, the left terminal of the AC input connector, and finally, to one of the two blades of the power cord. If at any point you lose continuity, you have located a problem. Pay special attention to the solder on the pins of L010 and L011.

All of this tests pass all the way out to the cord.

If you got continuity all the way out to the power cord, start by putting one probe on pin 3 of the bridge rectifier, and working your down the right hand side through the NTC, the right terminals of L011, the right terminals of L010, the terminals of the fuse, and finally the AC connector and the power cord.
PlainBill

Two bottom solder points for fuse failed and right side of AC in failed, also cord test failed The right solder point for the AC IN also looks like a bad joint. Possibly a blown fuse causing the right side to fail? However I am getting proper VAC through the fuse when plugged into an outlet.

Picture to explain things better. BLUE = PASS & RED = FAIL.

[PlainBill]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

All of this tests pass all the way out to the cord.



Two bottom solder points for fuse failed and right side of AC in failed, also cord test failed The right solder point for the AC IN also looks like a bad joint. Possibly a blown fuse causing the right side to fail? However I am getting proper VAC through the fuse when plugged into an outlet.

Picture to explain things better. BLUE = PASS & RED = FAIL.

You've found the problem. Good job of marking the results.

Bad fuse, bad solder joints on fuse holder, clips on fuse holder not holding the fuse tightly. Pull the fuse, test it (it's not beyond the realm of possibility that the fuse is intermittent), resolder the top AND bottom contacts on the fuse holder, reinsert the fuse, making sure it clips in firmly. Then verify the right side shows continuity from the lead on the bridge all the way to the end of the power cord.

PlainBill

[xclusiveplayer]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

You've found the problem. Good job of marking the results.

Bad fuse, bad solder joints on fuse holder, clips on fuse holder not holding the fuse tightly. Pull the fuse, test it (it's not beyond the realm of possibility that the fuse is intermittent), resolder the top AND bottom contacts on the fuse holder, reinsert the fuse, making sure it clips in firmly. Then verify the right side shows continuity from the lead on the bridge all the way to the end of the power cord.

PlainBill

Definitely a blown fuse, I took it out and the continuity test failed. Where can I find the exact replacement. I know it's a littel fuse and rated 3.15a 250v.

[xclusiveplayer]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

I think something disastrous just happened. I tried a cooper bussman fuse rated at 3.15a 250v ceramic fuse and the continuity test pass all the way to the cord.

As soon as I plugged in the power cord to the outlet a spark appeared and a nasty smell. Now one of the resister is all black out and possibly blown. Silly me to have tried this.

[xclusiveplayer]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

Just bought a new power supply from ebay for $50 shipped. Will update you guys further when it arrives. Picture of the blown resister below. Horrible mistake on my part.

Lesson learned: NEVER REPLACE BLOWN FUSE WITH DIFFERENT TYPE/RATING.

[xclusiveplayer]

Re: PHILIPS 32" LCD 32PFL7332D/37 WILL NOT POWER ON!

Is it possible to find a replacement resistor for this board. I remember the color on the resistor was brown black red gold = 1000 ohm axial type. Did a search on digikey but too many results showed up.

I believe the reason why this resistor blew was because I replaced the T3.15 250V (T=Time Lag) with an F3.15 250V (F=Fast Acting).

This is actually my first time really testing circuit, so I am just beginning to learn these information.

Question for Bill, what could cause the fuse to blow in the first place?