Table of Contents
Advertisement
Quick Links
Care and Feeding of Icom PW1 1,000 Watt Solid State Power Amplifiers
W6DE, November 2017
Use the following information at your own risk. No warranty is offered, implied
or expressed. I make no warranty as to correctness or completeness of the
following information. I am not associated with Icom, nor has the information
contained herein been approved by Icom. Modifying, repairing and/or
following these procedures may void Icom's original Manufacturer's warranty.
If you undertake any repairs and/or adjustments to your PW1 amplifier based
on this information you do so at your own risk.
This is a compilation of replies I have made to the Yahoo! PW1 on-line forum. This is loosely organized
around the causes of why PW1s fail, how to protect PW1s and how to repair some PW1 failures.
Setting up a PW1 with an Icom Radio:
Some folks find the ALC Level adjustment confusing. I drive my PW1 with an Icom 7600 radio which I'll
refer to as exciter and/or radio. I adjust my ALC level on 20 or 40 meters. I use the Icom supplied cable
to connect the radio ACC2 connector to the PW1 ACC1 connector. The Icom supplied cable routes the
ALC and PTT signals between the radio and amplifier.
The following advice about setting the ALC level is not the Icom recommended method. While I believe
this is a safer method to adjust the PW1 ALC, you follow this advice at your own risk. Here is how I
adjust the ALC:
--#1 rule: Never use the radio/exciter's antenna tuner when operating into a PW1!
--#2 rule: Everybody should have a dummy load. If you don't have one, borrow or buy one—tuning and
adjusting into an antenna is just looking for trouble. A good dummy load is always on the right
frequency and always has low SWR.
For the following steps do not engage the PW1's "TUNER" you should be operating into a matched load
of 1:1 SWR!
--PW1 should be connected to the mains power. The PW1 power can be on, but the "TUNER" and
"AMP/PROTECT" LEDs should be off. That is; the amp should not be amplifying and is in "by-pass"
mode.
--When setting ALC, set the PW1 meters to read PO (on the left meter), and ALC (on the right meter).
--Set your radio's meter on Power Out. Set your exciter power out to its lowest position. Set your
exciter to CW mode and use a hand key to transmit; a second way to generate the correct amount of RF
is to select FM and the press TRANSMIT key on the radio front panel. DO NOT use or connect the hand
mic to the radio, the mic may pick up sounds and effect the readings.
--In contrast to Icom directions: start setting ALC with lowest exciter power and then slowly turn up the
exciter's drive.
--When you get to around 100 Watts out of the exciter (remember the amp is off), Stop raising the
exciter's power, stop transmitting.
Copyright 2017, All rights reserved.
W6DE
Page 1
Advertisement
Table of Contents
Related Manuals for Icom PW1
Summary of Contents for Icom PW1
- Page 1 The following advice about setting the ALC level is not the Icom recommended method. While I believe this is a safer method to adjust the PW1 ALC, you follow this advice at your own risk. Here is how I adjust the ALC: --#1 rule: Never use the radio/exciter’s antenna tuner when operating into a PW1!
- Page 2 Care and Feeding an Icom PW1 --On the PW1 meter, switch the right meter from ALC to SWR, transmit again. Look at SWR. If it isn’t below 1.2 or 1.3, stop and find out why it isn’t closer to 1:1. Do not continue until you fix the SWR.
- Page 3 THIS. Please note: this is when will the failure occur not an IF the problem can occur! Yes, this means if you have a (1) PW1, (2) an Icom radio and (3) a computer on the CI-V buss you are just waiting for the problem to happen! This is how an “Automatic”...
- Page 4 VFO-B) and you requested/made a band change and you did not cancel split. On the new band your VFO-A and the PW1 went to the new frequency, but your radio was still in split and transmitted on VFO-B, which remained on the previous band. There is a 50/50 chance you will then transmit into a band pass filter that will try to eliminate your 1 KW signal all by itself.
- Page 5 It may be that you can find a match at a lower PW1 power level that still works without a tuner run-away.
- Page 6 Care and Feeding an Icom PW1 Copyright 2017, All rights reserved. W6DE Page 6...
- Page 7 Put cotton towels (NO synthetic material!) under the amp to help slide it around. In the end, you will scratch whatever you have the PW1 sitting on—don’t use the dining room table. Have a space with about an extra 12” to 18” around all sides of the amp while you work on it.
- Page 8 It may be that you can find a match at a lower PW1 power level that still works without a tuner run-away.
- Page 9 PA boards. The PA boards are sold by Icom for about $250 to $300. They are listed as a single item, but they come as pairs—thus, for a purchase of the Icom PA board item you get two identical boards. However, the PA boards do NOT come with the MRF-150 devices.
- Page 10 Care and Feeding an Icom PW1 across the PA assembly (when assembled this bar is partially hidden by the combiner cables). In addition there a lot of screws on the back panel. You also have to remove the back left corner foot to slide the PA assembly forward (required in order to slide the PA forward because the foot’s screw...
- Page 11 MRF-150 devices or just buy two from stock? You can replace a set of finals on one board of the four PA boards in a PW1. That is, you only have to replace the finals on the bad board. You should replace both finals on a board as a set.
- Page 12 Care and Feeding an Icom PW1 adjustments by adjusting each side separately with the other side biased off and then checked the current draw for both. The balance potentiometer is very, very touchy, only about 2% or 3% of the entire range of the pot is used to actually adjust the bias.
- Page 13 Care and Feeding an Icom PW1 Regarding: My PW1 won't tune up on 6 meters even into a dummy load. All other bands will put out 1000 watts but not on 6 meters. Note: This is symptom can also apply to other bands not working.