jvc av-36f702! won't turn on. timer light flashes red.


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jvc av-36f702! won't turn on. timer light flashes red.

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erickeri
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Jul 20, 2008, 7:33 PM

Post #1 of 16 (11468 views)
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jvc av-36f702! won't turn on. timer light flashes red.	Can't Post

I got a jvc av-36f702 that won't turn on. The front panel L.E.D. light blinks.
I did some research and found posts about a 1000uf 50v cap that goes bad. But the problem is that I can't find the location of that cap.
Is it possible that there is no location or bad cap and that there is a different problem?

When you turn the TV on you can hear it charge up and then go out. I can hear the relays!

Repair man
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Jul 21, 2008, 5:23 PM

Post #2 of 16 (11441 views)
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Re: [erickeri] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

It sounds to me like it is either a bad vertical IC or possibly a bad Flyback transformer.
A test for the flyback transformer is to desolder the collector of the Horizontal Output Transistor, apply a cable signal to the set and try powering on the set; if the it comes on with audio an no video then you have a bad flyback.
The only test for a vertical IC is to change the vertical IC. -- Dan

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erickeri
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Jul 21, 2008, 5:48 PM

Post #3 of 16 (11438 views)
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Re: [Repair man] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

In Reply To

I have changed a horizontal output transistor and a flyback once before on a different tv. (easy to do) this tv has 2 piece's that look like the H.O.T. I'm not sure which one is the H.O.T.
Which one is the vertical IC?
When you turn the TV on you can hear the relay then you can hear the tube charging up then it goes into safe mode! (powers down)

I double checked and I found the H.O.T. (it says D2645) it has 3 pin leg. The other one has 5 pin leg so that isn't it..

Now I should remove the H.O.T right? then try to power it up.

(This post was edited by erickeri on Jul 21, 2008, 6:03 PM)

erickeri
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Jul 21, 2008, 7:15 PM

Post #4 of 16 (11432 views)
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Re: [erickeri] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

Ok I took the horizontal output transistor out. Plugged everything back together and I plugged in the tv.
I didn't touch anything. (meaning the power button).
red light came on about 6 secs later the red light started to blink. tried to turn the tv on but NO GO. (safe mode)

Repair man
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Jul 21, 2008, 8:23 PM

Post #5 of 16 (11429 views)
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Re: [erickeri] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

Solder the H.O.T. back in but only solder the Emitter and the Base of the transistor, do not solder the Collector (make sure the collector is not touching the print of the circuit), then try the set. If you have sound and no picture you then need to change the Flyback -- Dan

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erickeri
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Jul 21, 2008, 11:52 PM

Post #6 of 16 (11425 views)
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Re: [Repair man] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

Which one is the collector?
Lets say im looking at the chip 3 legs. (number of the chip facing me.) left middle right.

Thank you
Eric

Repair man
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Jul 22, 2008, 12:04 AM

Post #7 of 16 (11424 views)
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Re: [erickeri] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

It will be marked on the board. It could be on the top or bottom but it should say 'B' 'C' 'E' beside the legs, not necessarily in that order -- Dan

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erickeri
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Jul 22, 2008, 12:19 AM

Post #8 of 16 (11423 views)
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Re: [Repair man] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

I got it. Thanks It does say it on the board. C is the middle leg of the transistor. I will do what you said.. I will resolder the HOT back in and leave the collector out..
Thanks Repair-man!

erickeri
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Jul 22, 2008, 12:42 AM

Post #9 of 16 (11422 views)
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Re: [erickeri] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

I just tried it out. Still the samething. Plugged in the tv and red light comes on, about 6 secs later you hear a relay click and the red light starts flasking on the front panel.

Repair man
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Jul 22, 2008, 1:38 AM

Post #10 of 16 (11419 views)
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Re: [erickeri] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

Have you checked the H.O.T. to see if it is good or not? Do you know how to check it with a meter? I would try to replace it next and if that doesn't fix it, the next step to try is to replace the vertical IC. it is mounted to a small heat sink and can have anywhere from 6 to 10 legs. Vertical ICs often start with LA (example: LA7838) -- Dan

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(This post was edited by Repair man on Jul 22, 2008, 1:39 AM)

erickeri
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Jul 22, 2008, 1:58 AM

Post #11 of 16 (11416 views)
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Re: [Repair man] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

Where do i get the part numbers for the vertical IC and the H.O.T.
I do have a volt meter and have a little experience with solder and testing but not a whole lot..

erickeri
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Jul 22, 2008, 3:02 AM

Post #12 of 16 (11415 views)
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Re: [erickeri] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

Ok i found the vertical IC (LA7841).
How do I test the vertical IC and The H.O.T?

Repair man
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Jul 22, 2008, 2:33 PM

Post #13 of 16 (11408 views)
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Re: [erickeri] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

It's hard to explain how to test them but I'll try, it's often easy and cheap to change them.

You can but them both for under $5 . The H.O.T. is $2.15 and the vertical IC is $1.19 from HERE when ordering the H.O.T. you must add 2S in front of the part number 2SD2645

To test the HOT check to see if it's shorted across all of its legs, if it is it's bad.

The vertical IC has 7 legs and none of them should be shorted to each other.

To test for shorts using your meter, set it to the lowest setting on the ohm scale (or ideally if your meter has a diode setting use it). Touch the two leads of your meter together and observe the meter reading, this is a short. Now test between the legs of the IC, if you have this same short or same reading then the IC will be damaged and needs to be replaced.

To test the HOT, between the emitter and the collector it will read shorted, this is normal but it should not be shorted across any other legs, if it is in needs to be replaced.

When I say it's normal to be shorted across the emitter and collector, this is only for some Transistors, your 2SD2645 is one that will read shorted, this is due to some internal circuitry of that particular transistor.

To test these parts, they have to be out of the TV.

Dan

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(This post was edited by Repair man on Jul 22, 2008, 2:51 PM)

erickeri
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Jul 22, 2008, 4:57 PM

Post #14 of 16 (11398 views)
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Re: [Repair man] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

I'm going to order those parts. I didn't test them yet but For that price I will just order new ones. Before I order them. Just incase Those are not the problem whats the next part.
I rather order them all at the same time.

Repair man
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Jul 22, 2008, 5:36 PM

Post #15 of 16 (11392 views)
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Re: [erickeri] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

If the H.O.T. is shorted, a bad flyback transformer is usually what takes them out. I'd try the HOT and Vertical IC before ordering a flyback -- Dan

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If you (or anyone reading this post) have any further questions or need clarification please feel free to contact me direct; you can find my email address by clicking on my user-name.

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erickeri
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Jul 22, 2008, 6:32 PM

Post #16 of 16 (11391 views)
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Re: [Repair man] jvc av-36f702! won't turn on. timer light flashes red. [In reply to]	Can't Post

This tv set was repaired before. There are some wires on the top and some resistors soldered on the bottom.
there is a wire by the vertical IC. and the are wires by a chip that looks like an eeprom but it is smaller.
I'm just wondering if there can be a problem at those spots.
I wish I can post an image here. Here is my email address. If you want I can send you a picture. ericstheman@alloymail.com

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