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The Icom IC-PW1 Main Unit connects to the PX-1981 AC Power Supply CONNECT Assembly (A1A3).

The following is a description of the interface connections:

J4-1 J1-1 ID  PA Current Sample from PX-1981 for PW1 Meter-1 (ID)  
J4-2 J1-2 VD PA Voltage Sample from PX-1981 for PW1 Meter-2 (VD)  
J4-3 J1-3 REGF HI from Main Unit to Turn PX-1981 Fan ON at T > 50oC 1
J4-4 J1-4 REGHC HI from Main Unit (Drives HVSA LO) to Turn On HV (45V) 2
J4-5 J1-5 MAXI HI from PX-1981 when PA HV Current Exceeds 50A  
J4-6 J1-6 REGT HI from PX-1981 when its HV Regulator Temperature is Exceeded  
J4-7 J1-7 GND GND Ground Return between MAIN UNIT and PX-1981  
J4-8 J1-8 -13V -13V from MAIN UNIT for PX-1981 CONV-CTRL Assembly 3
J4-9 J1-9 GND GND Ground Return between MAIN UNIT and PX-1981  
J4-10 J1-10 H12 +12V from PX-1981 SUB-REG to power the PW1 (Low Voltage) 4
J4-11 J1-11 H12 +12V from PX-1981 SUB-REG to power the PW1 (Low Voltage) 4
J4-12 J1-12 SEL HI from MAIN UNIT to PX-1981 CONV-CTRL when 50 MHz is Selected  
1 The Power Supply Fan will remain on after the PW1 is tuned OFF (as required) until the temperature drops below50oC.
2 PA HV (+45V) is provided from the PX-1981 FIL-DC (A1A6) Assy. via EP19, 20, 21, 22 for PA1 through PA4.
3 PX-1981 CONNECT J4-8, J5-6, and CONV-CTL J1-6 should be labeled –13V (not –5V).
4 The PX-1981 REG-RELAY Assembly passes AC Power directly through to the SUB-REG (even when the PW1 and its associated HF Transceiver(s) are turned OFF).Therefore it should be noted that as long as the PW1 is connected to an AC Power outlet, the +12V, +18V, and –18V Power Supplies remain active (HOT).
Legal Notice and Disclaimer: I do not guarantee the accuracy of this information.It is provided for a general understanding of the operation of the PX-1981, which is not documented in the PW1 Service Manual (except briefly on the system Block Diagram as REGULATOR, PX-1981). Please understand thatI am not responsible for your use (or misuse) of it.

If you have information contrary to what I have provided, or have additional information, I wouldappreciate hearing from you.


Contents copyright © 2002 Ted Marston, WA2RPI, Rochester, NY 

A. Farson VA7OJ/AB4OJ created this page

Last updated: 09/25/2019

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