Lowband Mocom 70 audio

n3chu · Post by **n3chu** » Wed Jun 14, 2006 4:06 am

Hi all, I know, I know its an old radio. I seem to remember there was an audio mod for the transmitter to give the Mocom 70 more pleasing audio but I cant seem to find the artical. Maybe one or two caps changed??. cant remember. I have changed over to the Mitrek controls and Syntor-x mic. but that dosent change it. any help will be greatly appreciated. thank you. Davie n 3 C h U at atlanticbb.net

Will · Post by **Will** » Wed Jun 14, 2006 3:08 pm

Dave, I think I remember that mod, will have to look in my archives for it.
There may even still be some Mocom 70 parts in the storrage, gota take a look!!!

n3chu · Post by **n3chu** » Fri Jun 16, 2006 1:25 am

Thank you Will! I appreciate your help. P.S. why would a 42-50 Mocom 70 thats rated at 100 watts only put out 40 watts? maybe the driver with the little stud on top? thanks. Davie n3chu AT atlanticbb.net

bernie · Post by **bernie** » Fri Jun 23, 2006 8:35 pm

My two bits worth:
It has been many years since I worked on a LB M70.
I do not recall a mod in the audio circuit.

There are many reasons the PA may not come up to power:
Out of band operation comes to mind.
Test using a known good dummy load.
The PA transistors have many individual transistors on a single substrate, with on chip combining.
It is possible for a transistor to lose gain if an individual transistor fails.
I think the manual has a trouble shooting guide.