Toshiba 32HL86 Sound + Backlight - No Pic

[mmartell]

Suspect tcon but impossible to test for voltage as it is mounted beneath the metal panel all the other boards are screwed down to. I tested the fuse F1 which was good then inadvertently found it shorted to ground. Removed all cables/ribbons from it and was still shorted. Removed tcon and reassembled set.

I turned it on looking for 12v at the lvds cable but only found 5.25v among other lower voltages. There was no input connected at the time.

Should i not be seeing a 12v supply at the lvds connector ? Don't pretty much all tcons use a 12v supply ?

[mmartell]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

D301 by the fuse was found to have a crack in it. Removing it cleared the short circuit condition. Fuse F1 is still good.

The marking on it as per the pic below is CCD with KE printed below. Anyone know what value that is or what discreet component I can replace it with ?

[multimeter]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

http://www.datasheetarchive.com/ccd%...datasheet.html

[mmartell]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

Thanks. I googled it and got nothing. I've never even heard of a "variable capacitance diode". Are these common ? I was hoping to harvest an smd diode from a junk board in my small pile.

[mmartell]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

I have here an HS1M, an SK14 and an SK34 which are the same form factor, the latter two which are Schottky I think. Would it be ok to replace the original diode with one of these or even a regular IN4007 ?

[budm]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

Is the banded side connected to the fuse and the other end is connected to Ground? If that is the case, then it is more likely to be TVSS/clamping diode.

[mmartell]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

Yes it is bud. I know that you and some others here can replace components by understanding the circuit they are being used in but as a rookie I fall short. Would you mind explaining what you mean with repsect to what might be a suitable replacement part ?

[budm]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

BTW, the LVDS will not be at 12V, they are active with very high frequency in 100Mhz range and likely to be <5V, you will need scope to check them.
Do you get 12VDC at both ends of the fuse (black probe on the chassis)? If you do have 12V then if nothing else is damaged, the T-CON should work without that Diode for now.

[mmartell]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

That's the thing I can't check the voltage at the tcon because of the way the damn thing needs to be assembled to function. The fuse checks good. And by 12v at the lvds connector I meant the voltage to drive the tcon not the signal voltages. I only saw 5.25v but as it turns out the tcon was likely dragging that voltage down.

Ok will try without the diode. If all goes well can you suggest a suitable replacement ?

[budm]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

OK, l look closer at the picture, the this T-CON runs on 5VDC not 12VDC. You can see V5V label close by the fuse.
Did some one work on this TV before? I wonder if more than 5VDC was applied to the T-CON.
The 5VDC is fed on the right side pin of the LVDCS connector which you should be able to trace that side back to the main board. You can post close up pictures of the LVDS connector on the main board then I may be able to show you the test point for the 5V feeding the T-CON board.
Shopjimmy does not have this model on the list.

[mmartell]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

That is wherw I already saw the 5v supply on the mainboard side of the lvds cable but was confused because I was expecting 12v. Thank you for confirming the proper supply to be 5v as I thought 12v was universal. I will try the tcon tomorrow morning.

That 5v supply was running direct to ground afaik and the fuse didn't even blow. Shouldn't a direct to ground short have popped it ?

[budm]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

That fuse should have popped, so I do not know why.

[mmartell]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

Ughh.. put it all back together and half the screen is messed up like a tab bond failure. Makes me wonder though since the tcon had a component failure if it could be that. If you look in the corners on the bad side the raster is rounded slightly like a crt tube. Odd.

[mmartell]

Re: Toshiba 32HL86 Sound + Backlight - No Pic

Took it apart again and reseated the panel ribbons at the tcon and reassembled without the metal tcon cover. Was set to poke gently at the ribbons through some ventilation slots but when I turned it on all was normal. Guess the ribbons weren't quite seated right. Thanks to budm for explaining about the tvs diode.

This tv has one hdmi port but no digital tuner, just an old analog one. Oh well.