J
Jumbaliah
Guest
Hi, last year around this time my HR-S4700U SVHS vcr started acting
up.
See http://groups.google.ca/groups?q=jvc+jumbaliah&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=b83b4153.0209030858.6501b7ab%40posting.google.com&rnum=1
I found that the electrolytic caps were the problem and replaced every
one with 105degree versions with the same capacitance and at least the
same voltage rating. I didn't go into detail to match the ESR ratings
of the caps (maybe I should have). Well, just a few weeks ago my VCR
turned off and the display went dead. I got the 'here we go again'
kind of feeling and opened it up. I'm not sure but there seems to be
smoke marks on the perferated metal lid of the power supply. I don't
recall seeing it last year when I fixed it before. So, I think
something burnt up this time and that's why she died.
I just tried my scope (didn't have one last time) on the removed and
unloaded powersupply (PCB shows PB10559 as a model number/part
number). I followed the AC input (120Vac btw) through the fuse (not
blown) and the big inductors (LF1 on the PCB) to the bridge rect (D1).
The AC inputs (~) on D1 look identical to what's on LF1. The outputs
of D1 (the + and -) don't seem right, I'm getting about 8Vpp on each
that looks like a pulse train and not a rectified AC waveform. I did
notice when it first powered up I was getting something else from that
exact point. So I think that D1 is damaged. The smoke marks are
above the area where D1 is on the PCB.
Would caps with a different ESR cause problems with the other parts?
Would it cause an increase in current thus damaging D1 or other parts.
Any other points I should test? Any one know the part number for D1
or an equivalent? That part of the board is packed tight and it makes
it hard to see. Vlad, you answered my post last year and said you had
a service manual for your HR-S8000U, if you read this please respond.
I'd like a scan or two from your book. Or anyone else for that
matter.
Thanks for your help,
Jumbaliah
up.
See http://groups.google.ca/groups?q=jvc+jumbaliah&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=b83b4153.0209030858.6501b7ab%40posting.google.com&rnum=1
I found that the electrolytic caps were the problem and replaced every
one with 105degree versions with the same capacitance and at least the
same voltage rating. I didn't go into detail to match the ESR ratings
of the caps (maybe I should have). Well, just a few weeks ago my VCR
turned off and the display went dead. I got the 'here we go again'
kind of feeling and opened it up. I'm not sure but there seems to be
smoke marks on the perferated metal lid of the power supply. I don't
recall seeing it last year when I fixed it before. So, I think
something burnt up this time and that's why she died.
I just tried my scope (didn't have one last time) on the removed and
unloaded powersupply (PCB shows PB10559 as a model number/part
number). I followed the AC input (120Vac btw) through the fuse (not
blown) and the big inductors (LF1 on the PCB) to the bridge rect (D1).
The AC inputs (~) on D1 look identical to what's on LF1. The outputs
of D1 (the + and -) don't seem right, I'm getting about 8Vpp on each
that looks like a pulse train and not a rectified AC waveform. I did
notice when it first powered up I was getting something else from that
exact point. So I think that D1 is damaged. The smoke marks are
above the area where D1 is on the PCB.
Would caps with a different ESR cause problems with the other parts?
Would it cause an increase in current thus damaging D1 or other parts.
Any other points I should test? Any one know the part number for D1
or an equivalent? That part of the board is packed tight and it makes
it hard to see. Vlad, you answered my post last year and said you had
a service manual for your HR-S8000U, if you read this please respond.
I'd like a scan or two from your book. Or anyone else for that
matter.
Thanks for your help,
Jumbaliah