Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

[OCybress]

I just got this Tv from a neighbor today. He said he plugged his computer into it and when he turned it on the screen went blank he said it had happened to him once before but he left it alone for a while and it worked fine. Now its toast so i took it off his hands.

Iv torn the tv apart and looked at everything. The PSU is a IPOS150rev1.8 with no signs of dmg except one on the bottom of the board pic 1. the tv will power on with a red light and nothing else you can hear the speakers kick on but that's it. I've done some research on these forums and a few others and found that D10 is usually to blame I don't have a multimeter at my disposal as of yet. So I cant test voltages. "see what i can do to find one" on the bottom of the board where the leg of the Diode D10 connects the trace seems to be lifted off the board slightly. is this irreversible dmg to the board or can i just solder a new trace? Any help on this would be great would love to put this tv in the living room.

[steve2]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

The trace being lifted isn't hurting anything. As long as the pins are soldered to it good. The trace isn't broken. You can put a drop of super glue under it and hold it with a small screwdriver till it dries or leave it as it is. I guess that's D10 that is connected to the heatsink (pic 3). The heatsink looks like it got pretty hot. What's the number on the side of the diode?

[OCybress]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

Thanks for the fast reply.

the number on the side of the diode is
B608
R303

pretty much what i thought about the trace just double checking. everything els on the PSU and the main board look fine nothing out of the norm that i can see. trying to get my hands on a mutli.

[Dgtech]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

I was one of the ones that had found D10 to be bad. The component was labled as an HER304 or something like that. I'm glad that you were very descriptive in your post because I read somewhere that these TV's tend to die when they are trying to be used as a computer monitor. In fact, someone suggested putting glue over the VGA connector just to make sure nobody does this. I havent looked into it to determine why this is so.

I got one on my desk right now that has similar boards. Polaroid 32 with an IPOS Rev 1.5 i think. This one was simply two caps that killed the backlights.

Whenever you get a meter from someone this will be an easy check on the diode.

[Dgtech]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

Here is my post on the first one of these that I worked on. It was a Memorex with the same boards.

https://www.badcaps.net/forum/showthread.php?t=12886

[OCybress]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

thanks DGtech your post was one of the ones I came across. read the hole thing

[OCybress]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

I'm getting a multi brought to me soon tonight. I was wondering if you could tell me what voltages to expect coming off of or going into D10 and if there wrong where to back trace to. It's been a while since my training in the military for electronics "mainly a computer and console guy now". and if and probably is if the D10 is bad you got a link as to where i can buy one saw you mentioned one for round 3$ but i didn't see a link to it.

[OCybress]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

Ok so i got the Multi but im not used to this type of mutli and its been a while since iv used one. any direction on exactly how to use this one to check this diode and other components would be greatly appreciated "a refresher of sorts "

[OCybress]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

lol answered my own question. So i tested the Diode with x 10Ω and the reading was 0Ω with the black connected to the anode and the red connected to the cathode. same when reversed both read as 0Ω.

Testing a diode with an ANALOGUE multimeter

* Set the analogue multimeter to a low value resistance range such as x 10.
* It is essential to note that the polarity of analogue multimeter leads is reversed on the resistance ranges, so the black lead is positive (+) and the red lead is negative (-)! This is unfortunate, but it is due to the way the meter works.
* Connect the black (+) lead to anode and the red (-) to the cathode. The diode should conduct and the meter will display a low resistance (the exact value is not relevant).
* Reverse the connections. The diode should NOT conduct this way so the meter will show infinite resistance (on the left of the scale).

[steve2]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

You are right. The diode is shorted. That is with the diode out of circuit? If it's still in the board, you need to unsolder one end of it, pull it out of the board and check it. Your meter is different, but no diode will read 0 ohms, unless shorted.. What keyboard button is the OHMS/Omega symbol on? The replacement diode they used is an NTE576. http://cgi.ebay.com/NTE-576-SI-Gener...item256320aa42 There are many places that carry them but this one is $1.49 & $1.50 shipping plus free shipping if more than 1 bought.

[OCybress]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

Got a digital Multi now. Ok so i pulled D10 and got a 7.8ohms and 0ohms reversed "pretty sure im not very good at testing diodes lol". so i put it all back together and started testing

CON3
20V = 23.7vdc
AGND
GND
GND
12V = 11.5v - 11.6vdc
5V - no wire
5VSB = 5.09vdc
STB = 4.7dc

CON4
GND
no wire
BK_ON = 0.0vdc
no wire
no wire
APWM = 3.0vdc

none of those values change when i hit the power button cept on the point in this pic. when i push the power button it goes from 3.5vdc to 0.0vdc. and it looks like it has been referbed at one point in time. left of the point im checking are 3 risisters. connected to one point i get 0.0v on all.

anyhelp? would be great. and if im doing anything wrong plz let me know so i dont waste time trying to replace something i thought was bad.

[steve2]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

The digital meter probably has a diode checker on it. On the ohms scale you just read it on , it is shorted. Most digital meters have a diode symbol, you may have to hit range switch or function or something to go to diode (which should show on the display).

[OCybress]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

You are right. The diode is shorted. That is with the diode out of circuit? If it's still in the board, you need to unsolder one end of it, pull it out of the board and check it. Your meter is different, but no diode will read 0 ohms, unless shorted.. What keyboard button is the OHMS/Omega symbol on? The replacement diode they used is an NTE576. http://cgi.ebay.com/NTE-576-SI-Gener...item256320aa42 There are many places that carry them but this one is $1.49 & $1.50 shipping plus free shipping if more than 1 bought.

the Ohms button or combination is Ω U+03A9
Thanks Steve2 I'm going nuts trying to remember all this its been a long while since iv had to mess with a multi. and yes that was with the diode out of Circuit with the diode in circuit its 0ohms both ways.

The digital meter probably has a diode checker on it. On the ohms scale you just read it on , it is shorted. Most digital meters have a diode symbol, you may have to hit range switch or function or something to go to diode (which should show on the display).

ya your right it does have an Ohms symbol that's what i had it one when i tested the diode out of circuit.

[steve2]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

U+03A9 I don't get it. You type U+03A9 and then what?

[OCybress]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

U+03A9 I don't get it. You type U+03A9 and then what?

lol got it wrong its Alt+234 hold down the alt butten and hit 234 and you get Ω

[steve2]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

well, it worked on notepad, but when I tried it in message, it takes me back a page. Oh well, Ohms is a short word, so I will type it out. Thanks

[Scenic]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

lol.. doesn't seeem to be working properly. alt + 234 = Û and the other version i found on the net is alt + 8486 which also doesnt work for me as it gives me a "&"

[OCybress]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

weird 8486 gives me & and the 234 gives me Ω lol mm might be difference in OS to im running windows 7.

[Scenic]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

same. Win7 64bit w. Firefox 3.6

PS: lotsa symbols i didn't even know existed as such Oo
☢ ☣ ☭ ☮ ☯ ☂ ㎐ ㎑ ㎒ ㎓ ㎷ ㎸ ㎃ ㎄

[steve2]

Re: Polaroid 21-860-AZO-IPOS150H Rev1.8 Issue

ΩΩ woo hoo Win 7 64 here also. It worked after I hit NumLock. Scenic , you got some nice ones. Maybe I'll have to look em look and write em down.