Tom, I will attempt to help - you know that the problem is on the Control Board (and its connectors), so proceed this way.
First (with the Control Board plugged in), be certain there is continuity between Control Board Q8 emitter and RF Board R98 (on the bottom of the board). Also check the integrity of the VRFDET signal on the Control Board, it should measure 820 ohms between U6 pin 2 and the end of RF Board resistor R66 (checking the connectors too). Then check the other end of things - Control Board U8 pin 2 to the inner end of R22 (marked as D3 on the board). Check the voltage at the collector of Q8 - should be 8 volts both for transmit and receive. Check all the components shown on the part of the Control Board schematic in the upper left section marked 'ALC'. Are all those parts correctly connected? Especially check the location of the ones mounted on the bottom of the board. If all is correct with everything above, it should provide power control. 73, Don W3FPR > -----Original Message----- > > anyone advise > i have a problem on controll board > no control over trans mit out put > with power control set to almost minimum i get full output > 15 watt > i thout it was proberbly a alc fault > changed u 10-u8 and q8 high out put dosent allow me to take > votage readings on transmit > i have used a known working controll board and every thing > works fine was > able to cary out alingment on transmit > thanks > g0lne -tom > _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
