Notes on AL-1200 (2) Linear
Bought by K8ND and picked up in Wheeling, WV, by K8ND in February 2009.
25 March 2009
Reassembled and set up in Curacao. Set filament voltage tap for 232 volts and blower on high speed. First QSO today on 14.167 with K8ND. In East closet. (Needs filament transformer and HV supply mods. Parts are on Curacao.
October 2010
T/R relay was hanging in RX now and then at the end of a transmission. Tapping foot switch cleared it. W0CG made several hundred QSOs and the problem seems to be clear now.
27 October 2010
Failed during heavy use on 15 meters making 10-10 QSOs. K6AM found a bias board that is not even on the circuit diagram that down-biases the tube during RX. He is removing the board entirely.
28 October 2010
Linear is back in service. K6AM found the cathode current path through that board to be open. He will take it back home and reverse-engineer it and possibly do a repair. Amp worked well at station # 2 for CQWW SSB, 14,328 QSOs on 10 and 80.
2 November 2010
T/R relay now hanging pretty much every other transmission -- removed from service.
11 December 2010
Board replaced by W0CG. Amp works perfectly now. Board was Ameritron PN 50-9453-1, "SA PCB assembly, 12/15/82 relay," price 36.28. Click here for the part invoice. Board replacement required unsoldering 15 wires from the old board, two of which were coax. Click here for W0CG's cheat sheet on making the repair. Here is a photo of the new board. Click here to see the old board prior to removal. The old board was cleaned up and put into AL-1200 spare parts in Box 9. Placed back in service at Station # 2.
13 January 2010
K8LEE ordered caps and resistors to upgrade HV power supplies. He will bring to the island in February. Click here for that Digi-Key order.
5 November 2011
HV supply failed. K8LEE installed a new HV module with success.
18 October 2014
Continues in service at Station 1.
31 March 2015
Removed to the storage for purposes of crop rotation. Worked perfectly for all of Fall 2014 - Winter 2015 contest season.