Polaroid 4011-tlxb black screen

[salo123]

Hi I'm working on a polaroid with black screen and not sound I bought the T-con
but still the problem I notice when I turn on the tv then I can't turn off the tv .I read some post about this problem and the problem can be the power supply and the main board but I really a don't know where to start (I don' know what is the part's name I think is the inverter because has connectors for the bulbs (back-light)has something like someone spill liquid on that part thank for your help

[selldoor]

Re: Polaroid 4011-tlxb black screen

Hi I cant see any references on this forum regarding this particular model.

We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, and problem parts (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

Please can you also update your profile with your Country and mains voltage

[salo123]

Re: Polaroid 4011-tlxb black screen

Thank you for your help and here are some pictures

[awyatt2]

Re: Polaroid 4011-tlxb black screen

have you checked for 24v going to the inverter. first check all the voltages they are marked on the board.also chek the voltage across the main cap the 450v 0ne meter on dc and be carefull it should be somewhere in the neighborhood of 250v if not the main is not starting. as i said carefully so you dont short it. i had this on one and tom 66 helped me with it the smaller cap was not letting the main fully charge.anyway the cap was a small one 10uf and a diode under one of the sinks was shorted. i think 17 volts was going to the inverter. when the 24v came up so did the backlights and tv

[selldoor]

Re: Polaroid 4011-tlxb black screen

have you checked for 24v going to the inverter. first check all the voltages they are marked on the board.also chek the voltage across the main cap the 450v 0ne meter on dc and be carefull it should be somewhere in the neighborhood of 250v if not the main is not starting. as i said carefully so you dont short it. i had this on one and tom 66 helped me with it the smaller cap was not letting the main fully charge.anyway the cap was a small one 10uf and a diode under one of the sinks was shorted. i think 17 volts was going to the inverter. when the 24v came up so did the backlights and tv

Depending on your mains voltage which is why I asked you to update your profile
Do any of the heatsinks come off easily.

@awyatt2 whilst the Inverter voltage check is a valid test, the way this reads is that you were working on the same model whereas I believe it was a different model with a totally different power supply.

[awyatt2]

Re: Polaroid 4011-tlxb black screen

power supply looks exactly the same, as does the rest of tv, still no voltage no work. the top of the sinks on mine came off by phillips screws that you see looking at the ps ,i think it was made by insignia if it is not the same it looks exact.either way i do not believe the power supply is fully starting.

[selldoor]

Re: Polaroid 4011-tlxb black screen

power supply looks exactly the same, as does the rest of tv, still no voltage no work. the top of the sinks on mine came off by phillips screws that you see looking at the ps ,i think it was made by insignia if it is not the same it looks exact.either way i do not believe the power supply is fully starting.

Sorry - I thought you were talking about the polaroid that Tom gave similar advice on.

[vinceroger69]

Re: Polaroid 4011-tlxb black screen

salo123 in you second picture your power supply can you remove the covers from the heat sinks and take some good pictures of the board?

[awyatt2]

Re: Polaroid 4011-tlxb black screen

have had quite a few polaroids in lately. all but one had the startup cap at least bad, i remember one had a small smd diode which was also bad. one the main cap was 20. esr on, and the last one had cold solder joints and a bad bridge rect.they all would not turn off(light would not go from blue back to red) when plugged in all lit red hit power button turned blue and then she stopped.tom 66 led me to the first one flm3201 and after that i started checking because it was cheaper than a new power supply. notice in the first line when i turn on tv i cant turn off, classic symptom of a failing supply,my experience at least.may not even be related but i am curious.if he dosent post anything else he gave up i guess.

[selldoor]

Re: Polaroid 4011-tlxb black screen

"if he dosent post anything else he gave up i guess."

Bit early to say people who post 6 pics dont usually give up, also the power board has Brown Blue Green/yellow ground lead so he may be in the UK.
We have had cracking good weather this weekend so anyone with kids will probably be out enjoying it - we dont get great weather that often. Its too hot for me so i am tapping on here.

[awyatt2]

Re: Polaroid 4011-tlxb black screen

the polaroid ps that were in the set i worked on had 2 but the provision was for three and a jumper changed the voltages. the mains were at least 450v with the ones that had two caps 500v 2 x 250v.just about bet the ps is made by insignia.

[budm]

Re: Polaroid 4011-tlxb black screen

This looks like FSP power supply, do you have the number as printed on the board? The aluminium plates come off easily. This power supply has PFC voltage booster, so check the DC voltage on that large cap in the primary side when the TV is off, and when the TV is on, it should have about 165Vdc when off, and about 400Vdc when the TV is on, if it does, then the PS_ON signal is OK since PS_ON is use to turn on the PFC and the 12/24Vdc power supply.

[awyatt2]

Re: Polaroid 4011-tlxb black screen

nope, that tv has been gone for a little over a week. sold it to buy another one to fix. last one was a phillips, had a bunch of cold solder joints on the ps. a little over three hours to desolder and resolder everything on it with 60/40 multicore solder. dont like the rohs(lead free) stuff

[salo123]

Re: Polaroid 4011-tlxb black screen

thank you for your help about the inverter the backlight is working because I can see the backlight (the backlight is always on) when I power the TV is not showing the picture and I can't turn off the TV here is some pictures from the power supply

[selldoor]

Re: Polaroid 4011-tlxb black screen

Ok Awyatt2 will point out which diode/ cap he replaced - There is one in Pic 8 perhaps you can test in circuit. Have you tested voltages down all the voltage out connectors on the board - can you list them on here by connecter/pin. We will also need good clear pics of the other boards -Fronts to start with.

Please can you update your profile with country and mains voltage.

[awyatt2]

Re: Polaroid 4011-tlxb black screen

the 47 and the 10 uf @ 50v near the mains xformer they both lead out to the controller chip. 47uf was the problem but i changed both for future failure. both were less than a buck 50.

the diode is surface mount underside the board he will need a meter to find it. there are several nested in a clump i did not save the number. if as in mine it will read shorted both directions.

tom 66 led me along on one and i went and checked some ps boards i had scrapped as well as several i have fixed since.it pretty much a no brainer less than a fwe dollars for parts or 50 to 150 on a ps.
thanks to Tom 66 on this he has saved me a fair bit on these that i was scrapping for parts, now they are mostly all repaired except two one has traces blown off the board and the other one is cracked .

selldoor he has never posted any voltages for any part of the set, we are working on assumption. if the power supply is working partly is all we can do is guess.right now he says inverter is working thay is only one part of the ps what about the rest of voltages?if the 12v, 5v 3.3v etc is not there it's not going to boot.maybe he has no meter to use, either way we are going to have to have some ref point as to where to start.

what i did notice even with the bad startup cap the ps would try to start and some of the voltages were ok. others would rise and fall real quickly. the inverters were the most starved though. if he has inverter voltages his problem lies somewhere else, however in each case the ps light would light as normal but you could not cut it off by the power switch, only unplugging set from ac would reset it.using polaroid as a ref the blue light signals set on red led stby, switch would cut on(blue) but not off(red).

[selldoor]

Re: Polaroid 4011-tlxb black screen

If only he would update his profile we could at least guess when he is meant to be about or asleep. Got over your Flu?
Having back lights is at least something as you suggested if he has a bad start up he may not have all the others. or not at the correct level.
Really he needs to check all the voltages at the power out connectors and list them.

[awyatt2]

Re: Polaroid 4011-tlxb black screen

nope the flu still has me, i will be 55 soon and feel every bit of it. just can'thake it when you get older. dont mean this in an akward way, but i have a friend who tries to fix tv's and would really be better off if he would stay out of them than try to fix them. this is true, he thought he was strapping fuses with wire and had a half dozen inductors and at least 9 sm caps strapped on a mainboard. when i told him what he had done he said i had did that. then i refreshed his memory, still had the email he sent where he had tried this.i won't be following him anymore inside a tv, if he pulls the back he finishes what he started.
back on the subject though,i agree wholeheartly with you. we can only assume until we have something concrete to go on. i had one tv last week , a phillips the thing was it would not start no matter what you did, had the voltage correct at the ps. i think to myself this thing has to have a bad fuse somewhere. spent two hrs finding and testing fuses and all was good. went to remove my probe from the powersupply plug and boom it started. yep bad solder ring on the inverter.first one ever in phillips.