Sylvaina 27 inch Tv Won't power up..

[Michael Kennedy]

I have a 1987 27 inch sylvaina tv. When you push the power button you can
hear the caps whining on and off on and off. Sort of a pulsing sound. The
tube doesn't light up as far as I can tell. The channel number blinks, like
it is not getting enough power. I think there is something wrong with the
power supply, but I have no idea where to start.

The model number of the tv is RNH4601 WA01
The Chasis model # is 26B1-06AA
Manufacture date October 1987

Any ideas?

- Mike

 

[William R. Walsh]

Hi!

Something in your TV is shorted or the regulation in the power supply has
become faulty.

What you are seeing (and hearing) is the power supply attempting to come up
and then shut down again. Normally this happens when the outputs of the
supply are shorted or even overloaded. Since you mentioned seeing channel
numbers flicker on and off on the set, it is very possible that the power
supply itself is where the fault lies and that the rest of the set is fine.
As a wild guess, I would say that bad capacitors in the power supply are
likely.

If you don't know where to start and you want to have the TV fixed, then it
might be advisable to take it to a shop and get an estimate on repair.
Provided the TV was working well prior to its failure the cost of repair may
be worth it. If you want to learn to repair electronics, I wouldn't start
with a TV set. There is just too much inside that can give you a nasty
surprise or even ruin the whole day (and a lot more) if you don't know
what's all going on in there.

William

 

[Michael Kennedy]

I know what not to touch inside a tv. I've read up on crt safety in the past
because I have had a few projects where I had to remove a tv from its case
and mount the crt in a fixture. I know how to ground the crt tube and caps.
My biggest problem is finding the bad component. Would you suggest replacing
all of the caps in the power supply section of the chasis? You said a short
in the power supply sounds like a possible problem, could I check the caps
with a ohm meter and just replace whichever one is bad?

One thing I just remembered. This tv gave me trouble (doing the same thing)
in the past and if it were upside down it would work. So I assumed that
there was a cold solder joint somewhere. I thought I had fixed it because
the solder was cracked on a large capicator and I reflowed it. It worked
fine for a few weeks. Then it started working some times and not others. A
good whack used to fix it. I havn't used the tv in a while but the problem
started again and now it just won't power on at all no matter how much you
hit it.

I think I will check for shorted out capicators with the good ole ohm meter
and look to see if that cap came loose again. I'm not sure that was the
problem to begin with, but the solder was cracked on it.

 

[Michael Kennedy]

I found the repairfaq.org tv page. It looks quite useful, but we will see if
I can fix this thing..

- Mike

 

[Michael Kennedy]

The problem was just some cold solder joints. I reflowed the solder and
Volia!