eHam Forums => Amplifiers => Topic started by: G0JKZ on May 17, 2010, 10:45:01 AM

Title: Microwave Modules MML 432/50 70cms Linear help needed
Post by: G0JKZ on May 17, 2010, 10:45:01 AM
Hi all.

Just picked up a second hand linear for 70cms and it has a strange problem. when powered up it runs fine, getting 40w out for 8w drive which is within the spec of the rf transistor. the problem is under power down conditions....

It seems to suck the 8w drive and lose it internally... showing no output on the power meter placed after the output. to me that sounds like a relay problem but it still goes into rx fine, and using the local repeater as a test source, is still allowing my old ft-726 to hear the signal.

When I opened up the case on the linear, it looks like someone has been playing in there, bypassing a bfy43, i'm assuming that this is an rx preamp circuit but I could be wrong....

Does anyone have a circuit diagram of this amp (they are almost as old as the ft-726 now) and Microwave Modules as a company haven't existed in the UK for a lot of years. Web searches don't seem to come up with anything.

Thanks in advance
George G0JKZ