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Inspection and Preliminary Reassembly
Inspect your work for good solder joints and freedom from solder bridges. Touch up any
questionable connections now.
Install the phono preamp adjacent to the selector switch using 6-32x1/4” screws and the
holes you drilled in an earlier step. You may have to finesse the existing wires on the
selector switch, but the new phono preamp PCB will slide in there nicely.
Final Sanity Checks
Here are a few last tests before you reconnect your PAT-4 to your music system. With
the top still off, plug in the AC mains. Turn on the power switch. Set your meter to DC
volts. Connect one lead of the meter to ground.
Be careful! These steps are performed with the power connected and
turned on!
Done
Done
The voltage on the NEG17P5 terminal of the new phono preamp should
measure between -17 and -18 Volts DC (with respect to ground).
The voltage on the POS17P5 terminal of the new phono preamp should
measure between 17 and 18 Volts DC (with respect to ground).
The voltage on eyelet 12 of both original preamp PCB’s should
measure between 36 and 40 volts DC (with respect to ground).
Prepare to Reconnect your PAT-4 to your Music System
Turn off the power.
Remove the AC plug from the wall socket.
Replace the cover.
Reinstall the four screws that hold the cover in place.
Reinstall the PAT-4 to your music system.
Notes:
o
Use the PHONO LOW input for your turntable. The other two PHONO
inputs, PHONO HIGH and PHONO CER are disconnected.
o
Given the 5 high-level and one phono wiring, then:
The TAPE HEAD input is a high-level input
The SPECIAL input is a high-level input
Record Playing Reminders
If it has been a while since you’ve played records here are a few hints that you may find
useful.
The ground wire between the turntable and the ground screw on the back-panel of
the PAT-4 preamp must be connected to minimize the hum. Usually, that wire
runs loosely along with the RCA cords.
Check your tracking force and anti-skating force. Re-balance your tone arm if it
has been a while.