Sylvania lc320ss2 LCD TV keeps blowing fuse

[kevinm34232]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

Yes

[tom66]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

25V will be fine... it is just preventing mosfet gate exceeding 30V on transient and start up.

[Beowulf]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

Sorry I've been a little away, little sick.

If you still need help I can provide more info of what I did, if it's not already here.

I dont have the TV with me anymore.

Also keep in mind that in my case I may have had more defective components than I should since somebody went and installed a higher rated fuse that I assume may have contributed to mess up some extra components.

Regards,

[kevinm34232]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

Yes I can still use some help. I replaced 2 shorted diodes D604 and D607, open R608,shorted Q600 and Q601, and plugged it in using a light bulb.

Bulb lit up for a second then went out. I had 120vac and 160vdc at main cap.

So I decided to replace fuse and see what happens. Plugged in and TV still dead, but fuse did not blow. After a little bit a saw a puff of smoke coming from area where I replaced the parts.. I unplugged it, and the heat sink for Q600 was VERY hot.. I think most of the components I replaced shorted out again, the 2 cement resistors are showing open now and were find before.

[kevinm34232]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

There are 3 SMD capacitors on the bottom of the board close to other shorted components, 2 show low resistance in circuit around 20 ohms, the other is around 250 ohms.

[kevinm34232]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

Well looks like Q600 Q601 D607 R602 R611 went bad this 2nd round time. 2 resistors R605 and R606 also read too low and out of spec. Read thru entire thread again and saw you had shorted D640 on secondary side bottom of board, mine was also shorted. So maybe this was what I missed before, will order the parts and try again.

I'd appreciate any other info you can share about what you replaced though, I did not replace photocoupler IC601 it seems to be OK. I pretty much tested everything else I could find..

[kevinm34232]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

As Im waiting on more parts for this one to arrive, I just have a question regarding the 4 SMD capacitors on the bottom of the board (these are the only components on the on the bottom of the hot section of the board except for 3 SMD 220k ohm resistors that test good. 3 are in close proximity to the shorted components C605 C606 and C608. The only way I know to test these is with my ESR meter in circuit and it shows open circuit/low capacitance not sure if that's correct way to do it tho, don't really wanna remove them and I heard they dont go bad too often..

Is it possible if one of these was bad to cause a major short the would short out the transistors and diodes?

[Beowulf]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

Hi,
I didn't have any defective surface-mount component other than the diode D640. I dont believe those smd caps are part of your problem.

Regards,

[kevinm34232]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

Finally got the parts and this TV is back to life. Here is the complete list of what I replaced:

Q600 - FET MOS TK10A50D - Mouser
Q601 - TRANSISTOR 2SC2120-Y(TE2 F T) - Ebay
D604 - DIODE ZENER 27BSB-T26 - Part # 568-5893-1-ND
D607 - SWITCHING DIODE 1SS133(T-77) - Part # 1SS133T-77CT-ND
D640 - DIODE SCHOTTKY SMD SK2B-TR - Part # SS210-TP
R602 - CEMENT RESISTOR 5W J 2.2 OHM H 10MM - Part # 280-CR5-2.2-RC
R605 - RES CARBON FILM T 1/4W J 220 OHM - Part # 291-220-RC
R606 - RES CARBON FILM T 1/4W J 180 OHM - Part # 291-180-RC
R608 - METAL OXIDE FILM RES. 2W J 0.18 OHM - Part # PNP300JR-73-0R18
R611 - CEMENT RESISTOR 5W J 2.2 OHM H 10MM - Part # 280-CR5-2.2-RC

[microvibe]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

i have same tv with power supply issue, i have replaced the shortedcomponents, i need q600 - tk10a50d. i have a bunch fet here can i substitue a tk10a60d instead of the tk10a50d. or what others would work

[tom66]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

There should be no problem with that substitution, the breakdown voltage is higher on the second part.

[microvibe]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

i replaced d640 that was shorted and also q600, pluged it all in andnothing, at least its not blowing fuses anymore but i get no clicking when power plugged in and no lights ethier. there is nopower at q600 fet any suggestions where to start

[kevinm34232]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

Did you check the list of parts in post #109, likely you have more bad components in the area..

[microvibe]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

i checked that list best i can , not very experienced testing the electronics but i can replace them. i had this board in for testing all they told me was q600 and d640, so i started testing the list on 200 ohm setting and i get no readings on the cement resistors, the other resistors check out, i dont have diode test function so i cant test the zener or switching diodes. i am not sure how to test the transistor as well.

are there other substitutions one can use for the cement resistors, i have tons of broken circuit boards i would like to salvage what i can. nothing i have has cement resistors that size and shape.

thanks

[kevinm34232]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

Most of those components will show short between pins if bad. The cement resistors are 2.2ohm resistors if you get no reading they are bad:

http://www.mouser.com/ProductDetail/...G8M/MHAUC2dQ==

[Lockley]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

Can someone tell me where to get the 1ZB36 D610 on board? Dave

[Hombre]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

It's a 36V zener diode (http://html.alldatasheet.net/html-pd...3/2/1ZB36.html), try ebay, mouser, digikey...

[gthorn]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

When testing the power supply on this tv or one like it (lc320em2f ) emerson ,does it need to be hooked up to the other boards or will it blow the fuse ? I read most of the posts about it and they are very helpful. I have parts on order and hope this fixes it. does anyone have a schematic or diagram for this tv? Thanks you've been a great help already.

[chris1123]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

I'm about to repair one and was wondering has anyone changed out D610
1ZB36 and used 1N4753A-T as a replacement? If not, does anyone know where to get the 1ZB36?

[budm]

Re: Sylvania lc320ss2 LCD TV keeps blowing fuse

1N4753A will be fine, it is 36V 1 Watt rating.