[Icom] PW1 AC Power Supply (PX-1981) Information for the Technically Inclined DIY

[Ted, WA2RPI]

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  I have had PW1 owners ask me about the interface between the PW1
MAIN UNIT and the PIX-1981 AC Power Supply, and therefore have provided the
following which may be interesting to other PW1 users with a technical
curiosity.


  ICOM PW1 / PX1981 AC POWER SUPPLY INTERFACE DESCRIPTION

  The Icom PW1 Main Unit (only) connects to the PX-1981 AC Power Supply's
CONNECT Assembly (Ass'y) A1A3.

  The following is a description of these interface connections:

MAIN UNIT J4-1 / CONNECT Ass'y J1-1: [ ID ]
PA Current Sample from PX-1981 for PW1 Meter-1 (ID).

MAIN UNIT J4-2 / CONNECT Ass'y J1-2: [ VD ]
PA Voltage Sample from PX-1981 for PW1 Meter-2 (VD).

MAIN UNIT J4-3 / CONNECT Ass'y J1-3: [ REGF ]
HI from Main Unit to Turn PX-1981 Fan ON at 50 degrees C.
This Fan will remain on after the PW1 is tuned OFF (if required) until the
temperature drops below 50 degrees C.

MAIN UNIT J4-4 / CONNECT Ass'y J1-4: [ REGHC ]
HI from Main Unit (Drives HVSA LO) to Turn ON PX-1981 HV (45V).

MAIN UNIT J4-5 / CONNECT Ass'y J1-5: [ MAXI ]
HI from PX-1981 when PA HV Current Exceeds 50 Amps.

MAIN UNIT J4-6 / CONNECT Ass'y J1-6: [ REGT ]
HI from PX-1981 when it's HV Regulator Temperature is Exceeded.

MAIN UNIT J4-7 / CONNECT Ass'y J1-7: [ GND ]
Ground Return between MAIN UNIT and PX-1981.

MAIN UNIT J4-8, CONNECT Ass'y J1-8: [ -13V ]
-13V from MAIN UNIT for PX-1981 CONV-CTRL Ass'y.  See Note 1.

MAIN UNIT J4-9 / CONNECT Ass'y J1-9: [ GND ]
Ground Return between MAIN UNIT and PX-1981.

MAIN UNIT J4-10 / CONNECT Ass'y J1-10: [ H12 ]
+12V from PX-1981 SUB-REG to power the PW1 (Low Voltage).  See Note 2.

MAIN UNIT J4-11 / CONNECT Ass'y J1-11: [ H12 ]
+12V from PX-1981 SUB-REG to power the PW1 (Low Voltage).  See Note 2.

MAIN UNIT J4-12 / CONNECT Ass'y J1-12: [ SEL ]
HI from MAIN UNIT to PX-1981 CONV-CTRL when 50 MHz is Selected.

  Notes:

  1. The PX-1981 CONNECT J4-8, J5-6, and CONV-CTL J1-6 lines are -13V (not -
5V).

  2. The PX-1981 REG-RELAY Ass'y passes AC Power directly through to the
SUB-REG Ass'y (even when the PW1 and it's associated HF Transceiver{s} are
turned OFF). Therefor it should be noted that as long as the PW1 is
connected to an AC Power outlet the +12V, +18V, and -18V Power supplies are
active (HOT).

  3.  PA HV (+45V) is provided from the PX-1981 FIL-DC (A1A6) Ass'y via
EP19, 20, 21, and EP22 for PA1 through PA4.

  Legal Notice/Disclaimer:  I do not guarantee the accuracy of this
information, it did
not originate from Icom, is my interpretation, and is only 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 that I'm not responsible
for your use (or misuse) of it.

  If you have information contrary to what I have provided above, I would
appreciate your passing it on to me.

  I would like to hear from anyone with the Blue Book, as I'm sure that we
could share information that would be beneficial to us.
  Thank you in advance, and for this correspondence please contact me direct
at
wa2rpi@netacc.net.

  Ted WA2RPI, Rochester, NY