vm
Video Corner
Servicing the Hitachi VM Series
camcorder
By Timothy W. Durhan
VHS camcorders from all manufactur-
ers have a lot in common. They have to
have a lot of similarities in order to record
and play back on the same VHS tape cas-
sette. On the other hand, manufacturers
also have a great deal of freedom in the
details of how they design and construct
their camcorders.
This article will describe procedures
for servicing Hitachi models VM 3000
through VM 5000 camcorders. Many of
the problem symptoms and actions to cor-
rect the problems will also apply to other
brands and models of camcorder.
Hitachi manufactured thousands of
camcorders in the late 80’s as models VM
3000 to VM 5000. Radio Shack, RCA and
Sears sold these units too, using their own
names and model numbers. All feature
the same tape mechanism. The capstan,
Durhan is an independent consumer electronics
service
ing
technician
and
a
freelance
technical writer.
mode cam and tape wind functions are
actuated by belts.
Symptoms of worn rubber parts
You probably know rubber parts dete-
riorate in time, even if they’re not used
often. Chances are, a five or six year old
camcorder will need new rubber. Some
common symptoms of worn belt prob-
lems include:
l Tape starts to load, then camcorder
shuts off.
*Tape runs, then after a while, shuts off.
l Camcorder eats tapes.
l Tapes won’t play or record.
If you have serviced VCRs with simi-
lar problems, you know it’s not too diffi-
cult to replace worn rubber parts.
Many VCR technicians are reluctant to
service camcorders, even though they
wouldn’t think twice about opening up
and repairing a hand held remote control.
If you can repair a remote control unit
without destroying the case or losing any
of the buttons, performing a mechanical
repair on a camcorder shouldn’t be too
difficult. Lost screws, pinched wires and
broken pc boards can be avoided by using
a systematic disassembly and reassembly
procedure.
Getting started
Start by powering up the camcorder
using the customer’s ac adapter, since a
defective battery may also be the cause of
any of the symptoms mentioned earlier.
Moreover, there is nothing more frustrat-
ing than running out of power in the mid-
dle of a repair. If your customer didn’t in-
clude the adapter along with their cam-
corder, put this repair on hold until they do.
Slide the power switch to on, and press
eject. If the mode belt is in good shape,
the cassette lid should pop up. If it doesn’t
1. Upper Cylinder (Video Head)
2. Audio/Control (A/C Head)
3.
Dew Sensor
4.
Pressure Roller
5.
Capstan Motor
6.
Capstan Flywheel
7. Take-up End Sensor
8. Take-up Reel Disk
9.
End Lump
10. Take-up Guide Roller
11.
Supply Reed Disk
12.
Tension Band
13.
Tension Arm
14. Supply Guide Roller
15. Supply End Sensor
16.
Impedance Roller
17. Full Erase Head
18.
Cylinder Brush
Figure 1. Tape transport mechanism-Top View.
60 Electronic Servicing
&
Technology November 1993
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