148 GTL post clarifier mod alignment

Shadow · Post by **Shadow** » Friday 21st Nov 2008, 11:22

Hey guys, im hoping someone can help me out here. I recently unlocked the clarifier on my PC-412/MB8719 148 GTL using Ricks method (BTW, thanks Rick!)

1 Remove D52
2 Remove R44
3 Remove R174 and solder a jumper in its place.
4 Unsolder the red wire that comes from the Voice Lock pot from the PCB and solder in to pin 1 IC4 MB3756.
5 Change R175 to a 1K

After that I adjusted L21, L22, & L23 to bring the radio to frequency on LSB, AM, & USB with the clarifier knob centered. Is there something else I need to adjust? It seems as if my RX is off frequency (transmissions are hard to understand) I've also noticed that my NB switch has little or no effect. Everything else seems to work fine.

euhara · Post by **euhara** » Friday 21st Nov 2008, 16:29

There is another setting you need to do to center the transmit and receive to the same frequency, I'm not a tech but I believe VR5 or VR7 centers the frequency, also I believe CT2 needs to be adjusted you can find the alignment procedure at cbtricks.com radio information. So don't take my word for certain.

Hope this helps you,

Regards, Jim

Shadow · Post by **Shadow** » Friday 21st Nov 2008, 16:58

hey thanks man, i know that there is something else that needs to be done. I once got a cobra 29 from someone that had the same problem and it was an easy fix, im assuming this is along the same lines but gotta find the right thing to tweak.

RedEye · Post by **RedEye** » Sunday 21st Dec 2008, 1:31

I may be wrong, but when you remove R44 the unit will adjust RX/TX together. VR5 or VR7 is not in the circuit anymore.

I had the same prob a long time ago, Rick corrected the procedure for me, look here in this forum...

http://www.radiomods.co.nz/forum/viewto ... =5274#5274