I have a Sony VCR Model # SLV-740HF (about 4-5 yrs old?) that died during a
recent storm during which we lost power several times. There were no
lightning strikes but high winds did bring power down a couple of times. A
day or so after, I went to turn on the unit and there was no response.

I am an electrical engineer so I was at least qualified to open it up and
further the damage. I removed the top and bottom covers, checked the line
input fuse (good), and looked around for burned components. I read AC on
the power supply board but on the test points of the regulated voltages (6V,
13V, 18V) there is no DC on any of them but I do see about 5VAC on the 18V
rail.

All the regulation circuitry appears to be in a rf shield/cage so I cannot
easily inspect this circuitry for visibly ruined components.

QUESTION: At this point this unit isn't really worth repairing is it?

ProdigySBC:
Power supply problems are "usually" some of the simplest and least
expensive repairs on a VCR for an experienced shop tech.... not always,
but usually.
The SLV-740HF is an excellent VCR and will easily outperform just about
any new, cheaply built machine regardless of price...
..... so I guess my suggestion to you is to TAKE it to a service shop
for, at the very least, a repair cost estimate, usually the price of a
cleaning, so you can make an intelligent repair decision with facts
instead of guesses.
If you want to give this a go yourself then you should visit the
website for this newsgroup at:
http://www.repairfaq.org/
there, with some searching you will find a wealth of troubleshooting
tips, repair proceedures, component testing methods and important
safety information.
Note that this VCR uses a switch mode power supply, or SMPS, and is not
as straightforward to troubleshoot and repair as a simple linear supply
so if this is beyond your patience level then, BEFORE you "do further
damage" at least get a repair cost estimate from a shop before you make
a decision to keep and fix or to discard.
electricitym
..
..
..

On Thu, 13 Oct 2005 02:10:22 GMT, "ProdigySBC_SUX"
wrote:

I have a Sony VCR Model # SLV-740HF (about 4-5 yrs old?) that died during a
recent storm during which we lost power several times. There were no
lightning strikes but high winds did bring power down a couple of times. A
day or so after, I went to turn on the unit and there was no response.

I am an electrical engineer so I was at least qualified to open it up and
further the damage. I removed the top and bottom covers, checked the line
input fuse (good), and looked around for burned components. I read AC on
the power supply board but on the test points of the regulated voltages (6V,
13V, 18V) there is no DC on any of them but I do see about 5VAC on the 18V
rail.

All the regulation circuitry appears to be in a rf shield/cage so I cannot
easily inspect this circuitry for visibly ruined components.

QUESTION: At this point this unit isn't really worth repairing is it?


The modular power supply(rf shield cage?) is most likely fried.
They're usually held down with one or two screws and can be easily
removed. Pull it out and check it out for a part #.
I don't know about Sony, however many vcr manufacturers used a PS made
by Panasonic that was prone to easy failure.
I used to get mine at Herman electronics in Miami at a fair price.
They can also be had at many local parts houses, at least in the
larger cities.
Herman might even have that PS if it's made by Sony etc....
If you can post the part # off the PS someone here might be able to
tell you if it's worth repairing.(some are, some not.)


http://www.hermanelectronics.com