G2 CHASSIS REPAIR TIPS        07-08-99

PROBLEM: Cassette insertion will not activate tape loading. Without a tape,
simply blocking the IR light to the takeup sensor should activate it (and it says
so right on the top of the carriage), but it wouldn't in this deck.  CAUSE:
cassette-down switch contacts are tarnished or misadjusted. Note that the
adjustment of this switch is critical. It is what caused the intermittant problem
(switch contacts were touching or corrosion was conductive across the gap) in my
deck. The switch assembly should be replaced, but it can be taken apart, cleaned,
and some anti-oxident applied. It's a bit tricky, but I repaired mine.
     This switch is mounted on the same plastic base as the record prevention
safety switch. There are only two wires going to the dual switch, so it may fool
you into thinking there is only one switch there. The two switches have a single
(hidden) ground return to the chassis. Note: if the two-wire plug from the
carriage to the deck is disconnected, when a tape is inserted, it will go in and
down but will immediately be ejected before loading tape. That's the symptom you
get if the switch never closes. It is the brown wire in the two-wire connector.
The red wire is for record prevention, and that switch is open with no tape or if
tape has no record tab. It closes if a tape is inserted with tab intact. The
carriage can be removed and reinstalled in the deck without mistiming the loading
gears to gain access to the switch. The VCR should be in the full eject position
where the loading motor will be at the end of travel.

PROBLEM: Another common failure in this deck is the carriage right side plate
moving away from the drive gear on the deck and allowing the carriage to jump
timing.  CAUSE: With the carriage removed from the deck, there is a small white
nub of plastic sticking up from the metal chassis. That nub was extruded through
a hole in the metal when the deck was manufactured. It is there to hold the right
side plate in place so the drive gear and slider gear do not slip. If the nub is
sheared off by too much force used to insert a tape or a bad mode switch putting
too much stress on the gears, you get the characteristic "clack, clack, clack"
sound as the slider gear and the drive gear jump timing. You can reset the timing
and the VCR will work again, but will continue to jump timing intermittantly...
and produce a callback! I'd be willing to bet a lot of those machines have been
thrown away because of repeat loading problems.
     There is a way to repair the deck if the plastic nub is missing, but take
care of the cause first. Replace (or at least clean) the mode switch (it's on the
bottom of the deck in this model). If you clean it, make sure to add some kind of
anti-oxident to the PC board inside. Replace or clean / lube the cassette-down
switch as well.
     Since the plastic nub is part of the chassis pan, it would seem to be
unrepairable. Glue would not hold the broken part in place (assuming you can even
find it again). Epoxy might, but it would need to be reinforced somehow. On the
last one I worked on, I positioned the broken part over the hole and marked a
pencil line on the deck where the nub was positioned. I noticed that it was not
directly over the hole, but offset towards the right side of the deck. I drilled
out the hole in the deck (but not through the plastic underneath) and inserted a
piece of large buss wire (from some 12-2 Romex house wiring) and pressed it into
the plastic with a hot soldering iron. I applied a blob of solder on top of the
buss wire and then trimmed and filed it to match the original nub of plastic.
With the carriage in place, the new nub fits the space in the right side plate
and holds the carriage tight into the drive gear as before.

Ray Carlsen
CARLSEN ELECTRONICS... a leader in trailing-edge technology.