They gave good pictures and there
were lots of different models available which had interchangeable
parts.
Today I got a VT130E in for repair. It had a nice charcoal coloured
front panel.
Unfortunately the Eject button was missing and part of the bottom
plastic edge had disappeared from the front left.
There was a cassette inside which was neither fully inserted
nor eject-able.
Obviously the cassette couldn't be ejected because the eject
button was missing.
Simple! Just fit an eject button and all would be well.
No. I removed the front panel and looked around for a replacement
from a scrap machine.
I found a scrap VT128 and detached its front.
It seemed to be all there so I fitted it to the VT130.
OK.. except it didn't have a button for slow motion.
Still
if the customer wanted slow motion
I can't
imagine for what
he could use his handset.
It clicked into place and I pressed "Eject".
Nothing happened.
I removed the cassette carriage by unscrewing its two securing
screws.
After winding the motor by hand the cassette slipped out.
I refitted the carriage and re-inserted the tape.
It slipped in and correctly flopped onto the deck floor.
I pressed "Play".
Motors whirred and the tape began to spool out around the drum.
The two threading arms started their threading action.
The right one was OK but the left one was a little reluctant
to engage.
I helped it by pushing it into place.
For a moment all seemed well then the machine aborted and turned
itself off.
I tried again and the same thing happened so I ejected the tape.
After rummaging around for ten minutes I found my dummy cassette.
This is a plastic affair with no tape and is supposed to fool
most machines into thinking a cassette with a tape has been loaded.
When I pressed "Play" motors whirred and everything
seemed normal except after a few moments the machine aborted.
Now this is not abnormal.
For many machines one must wind the take-up reel or the supply-reel
by hand to simulate a tape being wound or unwound.
I tried again and peered into the machine.
The left hand reel was turning briskly and the right hand reel
was stationary.
Surely this wasn't right?
I fiddled with the right hand reel.
There was absolutely no force being applied and what's more the
idler arm was firmly in place to the left.
I gently touched the pressure roller.
It was turning clockwise.
I thought for a minute or two.
I traced the motion in the air and thought that it should have
been turning anticlockwise for play.
The right hand reel should be rotating and the left hand reel
should be free to move, governed by the friction band.
Clearly here, the reverse was the case.
I tried "Play" again.
The VCR was definitely playing backwards!
Was it a faulty capstan motor?
I checked on my CD database for the capstan motor.
Willow Vale said that the VT130 capstan motor was the same as
that for the VT150.
I looked at my scrap VT128
Was the motor the same?
The labelling declared it to be so.. the wrong motor was fitted!
Could a previous repairer have fitted an incorrect motor?
Maybe the VCR had been repaired and it still didn't work so it
had been brought to me?
Not an uncommon occurrence!
I looked in the GRANDATA catalogue.
The VT128 capstan motor was the same as the VT 130 motor!
The motor was the correct one after all.
I removed the motor from my old VT128 and fitted it to The VT130.
With the greatest of confidence I inserted a tape and pressed
"Play"
It played backwards!
That wasn't the answer!
Maybe one of the power rails was off.
I didn't have a circuit diagram so couldn't check.
The VT128 power supply looked identical so after a lot of fiddling
with leads I'd replaced the VT130
PSU for the one from the VT128.
I inserted a tape and pressed "Play".
It played backwards.
Next I decided to use logic.
I traced the circuit and discovered a chunky motor controller
chip screwed to a chunky heatsink.
I removed the chip from the old VT128 and the one from the VT130
and fitted the one from the donor machine.. no mean feat as the
securing screws used a loktite compound and I had to use a stubby
screwdriver because of the limited space!
I inserted a tape and pressed "Play".
The VCR played backwards.
What next?
Ditch the VCR and tell the customer it wasn't a viable repair?
No. I'd already spent too long on it and I was now determined
to fix it!
Adjacent to the controller chip was IC602 a large microprocessor-sort-of-chip.
I reached for the unsoldering gun, positioned the donor machine
under the light, fitted my magnifying goggles and started to
unsolder the huge 64 pin chip.
After ages of unsoldering and fruitless tugging the chip eventually
parted company with the circuit board.
I repeated the actions on the customer's machine.
I then marked the two chips and soldered the replacement chip
into the problem video.
With a resigned look on my face I inserted a cassette and pressed
"Play".
Good gracious it works!
After a minute or two I'd discovered a perfect picture, perfect
sound and all functions working normally.
For interest I looked in CPC's catalogue for the chip.
It wasn't listed.
I looked in SEME's catalogue and it was £23.
I checked GRANDATA and it was listed at £22.
I sighed and made out the invoice
repair of Hitachi VT130
VCR
. £25
I don't know why I bother! |