NEC TV goes to stand-by when searching for channels!

[Shahriar]

Hi

I Have a NEC 21" TV (model= MH5) and it goes to Stand-By after 10-12 minutes working in normal condition with perfect

Image and it goes to stand-by very quickly in Auto-Searching mode but It doesn't go to Stand-by when the antenna is disconnected. I thought maybe sth. gets hot so
I made different parts hot with a Hair-drier(a device which is used to make Hair dry  :'( ). when COLD Power supply section and around it (Horizantal section; These two section are close to each other on Chasis) gets a little hot, The TV goes to stand-by faster (i.e. Every 20-30 SECONDS) I changed all tarnsistors and regulator and ICs around it but nothing special happened. Today I changed the tuner and what Happened!!!!!! the TV powers Up and goes to stand-by as soon as I connect the Antenna to the Tuner. The Components which I HAVE NOT changed yet are the diodes and Resistors. Can you guess what Happens?

P.S. The schemtic below is related to models with PIP. The Model I am working on does not have PIP Module

ThanX in advance
Shahriar

MH5.pdf

 

[vigosport]

Your  TV repair completed ?.

 

[Shahriar]

Dear vigosport

I am still working on it and it is going to become an impossible for me to do it.


ThanX In advance
Shahriar