I've had this Sony CCD-FX620 since it was new in 1994. A while back I
replaced the smd caps on the audio/video board and it restored the poor
picture and audio back to normal. I powered it up a few days ago, ejected
the tape that was in it, and inserted a brand new one. Then it went dead. I
tried a different battery and still nothing. Upon disassembly, I noticed
that one of the two 1.6 amp fuses, F951, in the power supply was open. I
mulled over the situation, replaced the fuse, and powered it up again but
this time with my bench power supply hooked up to the battery terminals. My
bench supply can be set to shut down at a predetermined current threshold. I
set it for about 1.8 amps and it powered up again no problem. I then tested
my battery to see if it wasn't holding a charge. It's a Sunpak 3000mAh
RB-90. I used the charger that came with the camcorder which is an AC-V25A
to charge this battery. I was quite surprised to see that my meter displayed
a reading of 8.18 volts. It's supposed to be a 6 volt battery. The schematic
indicates the battery input as the 6.5V unregulated supply. Despite this
finding, I hooked up the battery again to the camcorder and the same fuse
immediately blew. I've not come across this type of situation in the past
where a battery would charge to a voltage so high, that it would take out a
fuse in a portable device. I suppose there could be something wrong in the
camcorder which cannot tolerate an 8 volt input. I've had this battery for a
while and never had this problem before. I tried to disassemble the charger
but there is something preventing me from opening it without an extreme
amount of force. I don't want to use a crow bar on it just yet.

I'm anxious to hear the s.e.r. wisdom as to what could be causing the high
battery voltage or the camera's quick blowing of fuses.

Thanks for your reply.
--
David Farber
David Farber's Service Center
L.A., CA