My faithful Drake TR7 (SN 3119/ purchased new in April of 1979) has
developed a power output problem. The TR7 generates normal power output at
turn on, but after a few minutes of transmission the ALC becomes active and
starts cutting back the power, with the output shutting down to a fraction
(1/10th) of normal power. It appears to continue to work (CW, SSB, and psk),
but the reflected power jumps up (suggesting out-of-band energy). The
antenna is not the problem. I have checked the transmit relay, cable and
board connections, and switch contacts. All appear to be OK and not
contributing to the output problem. Running reduced power (25 watts) slows
down the ALC coming on a little, but not for long. The TR7 receiving is
stable and normal for all modes and all bands. The problem is not band
related either.

Has anyone seen this problem or have an idea what is going on?

Any suggestions on the best place to get it repaired?

Andy, K4YKZ

Andy - Many of the DRAKE TR-7 problems can be traced to its type of
motherboard construction with daughter cards plugging into it. The
large number of connectors get flaky with time and cause all sorts of
problems. Can't say yours is this, but suggest getting a can of DEOXIT
[ http://www.craig.com ] or some such contact cleaner and go over every
contact you can find. Be careful in getting the cards replaced
correctly and without messing up a coax or wire, etc. Also don't forget
all the decks of the band switch.

BTW - I sell a set of 13 Extender boards and the Digital Jumper board
that were sold as a Service kit by Drake years ago. If interested
contact me directly.

Good luck with a great radio.

73 Bob W7AVK



AK wrote:

My faithful Drake TR7 (SN 3119/ purchased new in April of 1979) has
developed a power output problem. The TR7 generates normal power output at
turn on, but after a few minutes of transmission the ALC becomes active and
starts cutting back the power, with the output shutting down to a fraction
(1/10th) of normal power. It appears to continue to work (CW, SSB, and psk),
but the reflected power jumps up (suggesting out-of-band energy). The
antenna is not the problem. I have checked the transmit relay, cable and
board connections, and switch contacts. All appear to be OK and not
contributing to the output problem. Running reduced power (25 watts) slows
down the ALC coming on a little, but not for long. The TR7 receiving is
stable and normal for all modes and all bands. The problem is not band
related either.

Has anyone seen this problem or have an idea what is going on?

Any suggestions on the best place to get it repaired?

Andy, K4YKZ