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-   -   Found a 36" Sanyo AVM 3659G Won't power up. (http://www.videokarma.org/showthread.php?t=177870)

MRX37 08-06-2008 07:58 PM

Found a 36" Sanyo AVM 3659G Won't power up.
 
The people I got it from said it flickered once, then went out for good. I plugged it in and heard a faint, high pitched sound coming from it. Pressing the power button did nothing.

Don't know when the TV was made, but it seems to be pretty new.

radiotvnut 08-06-2008 08:49 PM

That set probably uses a switching power supply. If it's making a high pitched noise, that probably means there is something shorted on the B+ line, loading down the power supply. My first checks would be the horizontal output transistor and the big diode in the B+ line.

You can probably get some semi-decent $ for that if you fix it. Around here, 36" sets still fetch $200+ in good condition. Don't know how long that trend will last, though.

radiotvnut 08-06-2008 08:51 PM

It's in Sams 4404 (too new for me). That set was probably made in the early 2000's.

MRX37 08-06-2008 09:56 PM

I found another answer that said it might be a bad HOT...

Crap...

Well, I dunno... I've been saving boards from 36" TV's... maybe I have a spare HOT on one of them.

andy 08-07-2008 12:47 AM

...

MRX37 08-07-2008 02:51 PM

Yep. Found a large 3 pin transistor near the flyback. (Q 404 ) It reads as a dead short on all 3 pins.

I can't really make out the numbers on it. I'm wondering if I can substitute another HOT from the board of another 36" TV?

Hell, what do I have to lose?

MRX37 08-07-2008 03:32 PM

Since I couldn't obtain a part # off the old HOT that I removed. I went and put in another HOT from a different TV chassis. However, I have NOT plugged the TV in yet.

What's the worst that could happen? My guess is the worst that could happen is the new HOT would short. Should I take some precautions before plugging the TV in?

andy 08-07-2008 04:18 PM

...

MRX37 08-07-2008 04:27 PM

I made sure the new HOT got a good amount of heat dope before mounting it to the heatsink.

Hoo... Okay. I guess I'll find out in a little while...

MRX37 08-07-2008 04:44 PM

Okay. Plugged it in, and the TV worked!... for about a minute.

The picture was concave, but it was there. After a minute, the TV shut down and that noise came back. The second it did, I unplugged the TV.

So all this TV needs is a better HOT...

radiotvnut 08-07-2008 05:31 PM

If the picture is concave, you have problems in the horizontal circuit. Probably bad caps around the flyback and HOT. These won't be electrolytics. They will be low value capacitors probably rated at a high voltage. If there are any diodes in that area, check them also.

MRX37 08-07-2008 05:54 PM

Could the pic have been concave from a HOT not rated for the TV? I used a hot labeled D1554 that came from a 19" TV.

MRX37 08-07-2008 09:45 PM

There are mostly lytic caps around the flyback. There is one disc cap, but it looks fine.

I've scavenged another HOT from a Magnavox chassis. I'll try it after I test the caps.

andy 08-07-2008 11:25 PM

...

radiotvnut 08-07-2008 11:53 PM

I checked tritronics website and the HOT should be a 2SD1880. An NTE2353 is the generic sub. This HOT does have the damper diode built in. The 2SD1554 is the same as an NTE2331, which is not as heavy duty as the NTE2353.


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