PRINCETON RECORDING AMP®™
(This is the model name for warranty claims)
4
SERVICE NOTES
1.
CHASSIS REMOVAL
is accomplished by first
removing the cabinet’s upper back panel. Then
remove the two (2) screws from the cabinet
side panel and four (4) screws from the top of
the cabinet that secure the chassis. Disconnect
the ¼” speaker plug from the speaker jack.
Remove the reverb assembly from the cabinet
by 1) unscrewing its cable clamp from the baffle
and 2) separating the 2 sets of Velcro restrain-
ing straps around the reverb. Then slide the
chassis toward the rear of the cabinet.
2.
IO PCB REMOVAL
is accomplished by remov-
ing the nuts, washers, and screws that secure
the IO PCB to the chassis’ rear panel. This
PCB will have to be removed in order to work
on the Main Tube PCB. With cable ties re-
moved, there is enough cabling to remove the
PCB and place it behind the back of the chas-
sis. Care must be taken to ensure that the
removed PCB is insulated from any exposed
metal or other hardware when power is applied.
3.
TUBE CONTROL PCB REMOVAL
is accom-
plished by removing the nuts, washers, and
screws that secure the Tube Control PCB to the
chassis’ upper front panel. With cable ties re-
moved, there is enough cabling to remove the
PCB and place it in front of the chassis. Care
must be taken to ensure that the removed PCB
is insulated from any exposed metal or other
hardware when power is applied. This PCB
must be removed in order to work on the lower
front panel effects circuitry found on the TZ/FX
PCB below.
4.
TZ/FX PCB REMOVAL
is accomplished by first
removing the IO PCB per item 2, Tube Control
PCB per item 3, and then partially removing the
Main Tube PCB. (Do not remove wiring from
the Main Tube PCB. Remove the 12 screws
securing the standoffs to the chassis. Also re-
move the tubes. Rotate this PCB so that the
standoffs face the back panel of the chassis.
Now there is enough room to remove the TZ/FX
PCB.) Remove all nuts and
washers from the
controls at the lower front of the chassis except
for the trans-impedance attenuator. This must
be disconnected from the board inside the
chassis at P23. Disconnect all fastons and rib-
bon cables from the TZ/FX PCB while cutting all
necessary cable ties. Next, remove two (2)
screws from underside of chassis first (these
are located directly beneath the heat sink) and
then the nine (9) screws around the board in-
side the chassis. Slide the board toward the
rear of the chassis until all potentiometers are
clear of the front of the chassis (wires from
transformer may be tucked under the board or
pulled through bottom of chassis if they obstruct
this step) and finally remove the board.
5.
MAIN TUBE PCB REMOVAL
is accomplished
by first removing the IO PCB per item 2. It is
recommended that as much troubleshooting
and rework as possible be performed with this
PCB installed in the chassis with the IO PCB
removed. Should you need to remove it, next,
remove eight (8) screws that secure the stand-
offs around the preamp tubes and then the four
(4) screws securing the power tube sockets.
Disconnect the ribbon cables from the main
PCB at P5 & P7. Numerous faston connection
receptacles will need to be disconnected from
their associated FASTON blade (keep notes!).
Some wires and all coax will need to be unsol-
dered to fully remove the PCB.
