Toshiba 37HVL66 Main Fuse

[mark2924]

the main fuse in my toshiba 37HVL66 tv keeps blowing and I"m having a hard time figuring out where to even start testing as nothing looks damaged. Any one have similar problems? I'll post a picture soon

[Dgtech]

Re: Toshiba 37HVL66 Main Fuse

did you check the bridge rectifier in the middle of the board -- right near the elbow? These are usually to blame.

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

What values should I be looking for?

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

everything seemed to test fine..... 70 ohms through those diodes sound right?

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

if i measure between these two different objects, my resistance is 1.2 ohms... im not exactly sure what they are, one is marked like a diode and the other a cap... but the don't look like thats what they are

[budm]

Re: Toshiba 37HVL66 Main Fuse

Can we see the good clear pictures of the bottom side of the board, the Blue component is the safety cap, the Gray component may also be a Ceramic safety cap or Thermister for in-rush current limiter.
I see the bridge rectifier, black rectangular, next to two diode DE02, 03. You should remove them to test them out off the board for true reading.

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

Sorry, had a long day... but here are those pictures... I should find the time to start testing parts off the board tomorrow and I will keep you informed... thanks for all your help so far.... battery just died as i tried to upload them from my camera.... ill post them at at lunch time tomorrow

[Dgtech]

Re: Toshiba 37HVL66 Main Fuse

Sorry I didn't get back to you. Type in the part number of that rectifier. A replacement should be easily found. Very cheap too.

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

Here are those pictures

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

d3sb 60 65 is what i can read on it

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

how can i test that rectifier? i've only got mild experience from when i was in class and wed take the diodes away from the bridge to test them individually

[budm]

Re: Toshiba 37HVL66 Main Fuse

Example of how to test bridge rectifier:
http://www.youtube.com/watch?v=dqkT6hF0O3E
Or just Google how to test bridge rectifier.

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

okay, ive got it tested, going from one of the sign waves and negative i get 0.8 ohms, going both ways, that classifies it as bad right?

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

yeah, i googled it, i was just unfamiliar with a bridge rectifier being in an ic.... im just now starting to dip my toes into the water a little further... thanks again for helping the new guy

[budm]

Re: Toshiba 37HVL66 Main Fuse

That is bad! You test it out off the board, right? It has to be removed from the board for testing since the board may have shorted load that will give you false reading.

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

my next question is, do i need that part number or can a get any 600v 4a rectifier?

[budm]

Re: Toshiba 37HVL66 Main Fuse

Same rating and the pin spacing that will fit the solder pads will be OK. So, did you test it out off the board? You should be to get it from Mouser or Digikey.
When you remove the bridge, use the meter to check the resistance between the pads for the + and - pins to see if it show very low resistance reading to be sure nothing else is damaged beside the rectifier.

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

I did, the pads for + and - where the rectifier would be?

[mark2924]

Re: Toshiba 37HVL66 Main Fuse

250 ohms sounds too low, what do you think?

[tom66]

Re: Toshiba 37HVL66 Main Fuse

250 ohms measured between + and - on board?