DRAKE TR-4CW - Chapter V: Maintenance; Service, Troubleshooting, and Covers

DRAKE
CHAPTER V
MAINTENANCE
5-1. SERVICE DATA.
We will check and align your transceiver at the
factory for a nominal fee if it has not been tam-
pered with. Transportation charges are extra. Any
necessary repairs will be made on a time and
material basis. Please write or call the factory for
authorization before returning your unit for align-
ment or service. Address your request for authori-
zation to:
R. L. Drake Company
540 Richard Street
Miamisburg, Ohio 45342
ATTN: Customer Service Department
Telephone: (Area Code 513) 866-3211
(Code-A-Phone Service after
1630 Hours E.S.T.)
WARNING
Extreme caution should be exercised
when the top and bottom covers are
removed. High voltage which is present
at several points can cause a lethal elec-
trical shock. Repairs and adjustments
should be made only by a qualified
electronics technician. Disconnect the
Power Supply from the TR—4C before
removing covers.
5-2. TOP COVER REMOVAL.
Remove the three top screws on each side of the
TR—4C and remove the cover by first pulling up
on the rear and then the front of the cabinet.
5-3. BOTTOM COVER REMOVAL.
Remove the three bottom screws on each side of
the TR—4C and lift the chassis out of the bottom
cover.
5-4. TUBE REPLACEMENT.
In general, most trouble in electronic equipment of
good design is due to tube failure. The best method
of finding defective tubes is by direct substitution.
It is best not to rely too heavily on tube checkers.
The TR—-4C has been designed so that, with the
exception of V8, V9 and V10, tubes can be replaced
without need for realignment. These tubes are to
be replaced with a matched set of the same brand
as originally supplied. If a different brand is used,
alignment of T7,T8, T9 and final amplifier neutral-
ization is recommended. Matched sets of Sylvania
6JB6’s are available directly from the factory. To
replace the 6JB6 tubes, it is necessary to remove
only the top of the final amplifier cage. To do this,
remove the sheet metal screws holding the PA cover
to the cage. A disc-handle is provided on the cover
to facilitate removal. To replace the PA cover,
simply reverse the process. Be sure the parasitic
suppressors do not short to the cage.
5-5. TROUBLE SHOOTING.
Careful consideration has been given in the design
of the TR—4C to keep maintenance problems toa
minimum. However, it is quite possible that some
problem will arise which cannot be cured by tube
substitution. If this occurs, it is suggested that the
TR—4C be returned to the dealer or you may write
to the Customer Service Department at the address
given in paragraph 5-1. Be sure to describe the
problem in detail. Include full information con-
cerning external connections, control settings, tubes
substituted, serial number, etc. Always include the
serial number when requesting service information.
Before returning equipment to the factory, it is
necessary to get prior authorization. In case of mal-
function, first check the power supply fuse, the
filament fuse in the TR—4C and the number 12
fuse lamp near the relay assembly for continuity.
The voltage and resistance charts in this chapter
should be valuable in isolating minor problems.