Notes on AL-1200(6)

Bought 8 March 2018 from K4JRS in Atlanta and picked up by NK4U, Tim Lemmon 11 March 2018.

SN 12392

I picked up the amp at the Hamvention from W8HC who was kind enough to drive it from Atlanta and keep it in St. Albans, WV until mid-May. It had two golf cart rides at the Hamvention to get to my car.

Tested at W0CG. Made QSOs on 20 meters, seeing easy 1600 watts of output into my perfectly matched monoband yagi. Packed this date for shipment in three separate pieces.

Assembled and placed in service at Station 1 by W0CG. Initial tests on 160 meters look good. Primary was wired exactly the same as the above photo from AL-1200 (4).

HV was popping about once every three minutes. N7IR replaced all HV components this date.

Somebody placed this in service in January after N7IR rebuilt the HV supply. It was used very hard in CQWW CW and in casual QSOs by K8ND.

Removed from Station 1 service by KB7Q and W0CG. Needs to be placed near bottom of pile.

K8ND removed the old T/R board. Did not quite complete the replacement of the board. W0CG finished the install and cleaned up the soldering (January 24). W8WTS found bad diode connection at board (January 25) and resoldered it. This was a factory defect. Amp works correctly now. In service at Station 1.

W8WTS is taking all three old bad T/R boards homw as a guide to reverse engineer new ones. There are still two good boards on site, part number 861-0453 Rev 3.

W8WTS also determined that part of the circuitry on the T/R board delays TX until the relay has keyed so that it won't hot switch.

All: I had posted a photo of the AL-1200 project on Facebook, and lamented that the T/R board replacement was a pain. Tom W8JI posted a reply today: "That board is a mess. The wiring is a mess. There are so many ground loops it is a wonder it works at all. Someone at MFJ stuck that board in without understanding or thinking about how RF works. https://www.ctrengineeringinc.com/relays/" The link is to a replacement relay board. $49. Information to keep in back pocket, since the T/R board is no longer available from Ameritron. 73, Jeff PJ2ND K8ND

You replied on Fri 05-Jan-24 13:53

G'day Tom, I'd like to order one (1) of these boards: $49 basic UNRS-12 12Vdc. Ameritron and other 12Vdc T/R relays Please advise how I should transfer payment to you. I am currently in Curacao. I'd like the board shipped to: Walter J Aucoin, Jr 581 BUCKINGHAM AVE MELBOURNE, FL 32935 He is coming to the island soon, and will bring the board down. 73, Jeff PJ2ND K8ND