Hi,

I got an SONY KV-M1421D Trinitron color TV.
It has a strange fault. If I turn on the TV it works great. Everything works
perfect. But after about 1 hour the picture gets darker and the sound gets
weaker. I can adjust it for a few minutes. But its get darker and darker.

Can anybody point me in the right direction for reparing my TV. I have got
electronic experiance but I can't find the fault.

Greetings Richard

Do some basic troubleshooting and post the results and then someone
might be able to point you in the right direction if you still are not
sure which way to go.
Some things you need to post:
What happens when you change channels in the fault condition?
Does the A/V inputs work (if it has them)?
Is the OSD also dark?
Describe how the sound gets weaker, does it just fade away or does it
start to get staticy and distorted?
... and any other troubleshooting results.

The repairfaq has some common faults on some older Sony sets you might
want to look at. www.repairfaq.org

Do some basic troubleshooting and post the results and then someone
might be able to point you in the right direction if you still are not
sure which way to go.
Some things you need to post:
What happens when you change channels in the fault condition?
Does the A/V inputs work (if it has them)?
Is the OSD also dark?
Describe how the sound gets weaker, does it just fade away or does it
start to get staticy and distorted?
... and any other troubleshooting results.

The repairfaq has some common faults on some older Sony sets you might
want to look at. www.repairfaq.org

CIP wrote:
Hi,

I got an SONY KV-M1421D Trinitron color TV.
It has a strange fault. If I turn on the TV it works great. Everything works
perfect. But after about 1 hour the picture gets darker and the sound gets
weaker. I can adjust it for a few minutes. But its get darker and darker.

Can anybody point me in the right direction for reparing my TV. I have got
electronic experiance but I can't find the fault.

Greetings Richard


I would start with the power supply, measure the voltages when first
turned on, then measure them when it starts to get darker, if one or
more is dropping then you know where to look.

"CIP" wrote in message
t.nl...
Hi,

I got an SONY KV-M1421D Trinitron color TV.
It has a strange fault. If I turn on the TV it works great. Everything
works
perfect. But after about 1 hour the picture gets darker and the sound gets
weaker. I can adjust it for a few minutes. But its get darker and darker.

Can anybody point me in the right direction for reparing my TV. I have got
electronic experiance but I can't find the fault.

Greetings Richard

Need more information. When it fails, what works and what doesn't. ie.
What happens on the A/V inputs? Is the OSD nice and bright? When you
change channels does it work momentarily? etc.

Also check out the repiarfaq for some common problems on older Sony sets.