Polaroid 1913-TDXB 3 Seconds To Black

[SgtRock]

Dear BadCappers:

--This Polaroid 1913-TDXB TV, Monitor with DVD, has the typical 3 seconds to black syndrome. I am pretty sure the problem is on the inverter board, but it does not stay on long enough for me to tell if all the lights are coming on. Attached are two pictures of the inverter board. Could some one please tell me how to get it to switch on, with just the board, and the power supply, so I can determine if the problem is lights, transformer, caps or what have you. The caps are HEC, and probably crap, but they look fine and have not yet been checked and will be replaced as a matter of course if the inverter board is otherwise good. If the inverter and the light are good, I will then check the caps for capacity, open, short and ESR. Otherwise I will probably part the unit out. I am not sure I need a schematic, but it would be nice to have one, just in case, if anyone happens to know where to get one.

"If it were not for electricity, we'd all be watching TV by candlelight"
George Gobel 1919 1991

Best Regards
Clear Ether

[tom66]

Re: Polaroid 1913-TDXB 3 Seconds To Black

Do you see a pin marked BLON, B/L or ON/OFF?

[budm]

Re: Polaroid 1913-TDXB 3 Seconds To Black

Since it has 4 lamps, you can have one lamp plugged in one at a time, turn it on and see if you can see the screen light up, do it in a dark room. the inverter transformer also has two high voltage windings, you can check the resistance of the windings.

[SgtRock]

Re: Polaroid 1913-TDXB 3 Seconds To Black

Dear Tom & Budm:

--Tom: The second picture I posted shows the following labels for the plug:
+12V +12V
GND GND
ADJ BON
GND PON
GND GND
SB SB
+5V +5V
--I assume that BON would likely be the pin you are talking about. Do I short that to the +5V or what? Thanks?

--Budm: I have power supplies for testing the CCFLs and will do so when it gets dark. In the meanwhile I have ordered another one of those universal 4 lamp inverters from Hong Kong, I am not sure if it has enough connections, but I wanted one on hand anyway. I also have spare bulbs to test the inverter with. I sure hope it is not the bulbs. The last one I had fixed a Star Logic M17ANA Monitor, which I am about to flog on eBay, funds getting short.

--T&B thanks as usual for your quick and knowledgeable help.

"If you build a better mousetrap, you will catch better mice."
George Gobel 1919 1991

Best Regards
Clear Ether

[tom66]

Re: Polaroid 1913-TDXB 3 Seconds To Black

BON - connect to 5V but best to use a 100 to 470 ohm resistor in series.

[SgtRock]

Re: Polaroid 1913-TDXB 3 Seconds To Black

Dear Tom:

--Perfect, thanks. I will report back soon.

--I have made a couple of attempts at reballing the 380 spot 0.5mm ARM for the 32" Vizio, but no luck yet. Very hard going, so damn small, but will continue to try.

"Did you ever get the feeling that the world was a tuxedo and you were a pair of brown shoes?"
George Gobel 1919 1991

Best Regards
Clear Ether

[SgtRock]

Re: Polaroid 1913-TDXB 3 Seconds To Black

Greetings Badcappers:

--I found that one of the lamps had gone red. I took the display apart and replaced the bulb with one out of a junker, and now it works. Hooked up to HDMI the screen is stretched out beyond the edges of the monitor. It that probably due to caps on main board, or are there other probable causes.

"I'll have the Alfalfa sandwich, and the smashed yeast"
Woody Allen 1935 -

Best Regards
Clear Ether