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M1225 Option Bd ?

Posted: Thu Feb 04, 2010 1:48 pm
by Satelite
Hello:
I have a Motorola M1225 UHF 20ch mobile radio that i have been sitting on for awhile and am now just getting around to repairing.
Did the repair and want to remove the hln9511a quick call bd.
After removing the bd i do not have any recieve audio and i do if i put the bd back in.
What do i need to do to be able to remove the option bd and return to normal operation for recieve audio ?
Im sure its more than likely in the rss programming or at least i think so.
Thank you.
Satelite

Re: M1225 Option Bd ?

Posted: Thu Feb 04, 2010 5:48 pm
by Bill_G
According to the manual there is a shunting resistor R551 between the input and output pins of the option board. Theoretically you should be able to install or remove the board without any problem. However, if someone removed R551 near J13, then your audio path would be dead with the board removed. According to the manual, R551 is located behind the display centered about pin 8 of J13 and parallel to the connector. It's 30k.

Re: M1225 Option Bd ?

Posted: Fri Feb 05, 2010 1:20 pm
by com501
The option board instructions say to remove the jumper(R551). At least they do on these ancient Scholer-Johnson boards I have here.

Re: M1225 Option Bd ?

Posted: Fri Feb 05, 2010 5:18 pm
by Bill_G
Well, there you go. Sweet. Easy fix.