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Plz help! M216 Low band will Tx OOB, won't Rx, need to tune!
Posted: Tue Apr 10, 2007 5:02 pm
by Paramedic606
I have a Radius M216 Low Band that I've SHIFT'd to program OOB to 33.46 & 33.52 respectively. The Radio will TX there but won't RX (even with open monitor). I've even bitbanged to change the MDF but the radio still won't receive. I think I have to turn down the spectrum just a touch (I don't use anything in the upper end)...can I just adjust a pot by a tiny bit or am I going to need tuning equipment?
Any help would be appreciated...THANK YOU, you guys are the best!!!
- Paul
Posted: Tue Apr 10, 2007 5:17 pm
by Max-trac
Is it a 36-42 split?
Tweak the VCO a little.
Posted: Tue Apr 10, 2007 7:53 pm
by Paramedic606
Yes, it is a 36-42 split...I know this is a DUMB question, but is the VCO readily identifiable and I should probably tweak it just a touch COUNTER-clockwise, eh?
Thank you for your reply!
Posted: Tue Apr 10, 2007 11:25 pm
by Will
There are two VCO's, one for RX and the other for TX.
Clockwise, need to add a bit of inductance....
Posted: Wed Apr 11, 2007 11:06 am
by Paramedic606
Thanks, Will...I'll give it a shot. You helped me out a few years back in the message board as well...nice to see you're still here!!
- Paul
Agawam, MA FF/PM
two pots...
Posted: Wed Apr 11, 2007 11:32 am
by Paramedic606
I popped off the silver cover inside the radio and thought I'd find the VCOs, only to find the firmware chip (and a few others). The only pots I see are two near the heat sink portion of the radio...a red one in middle and a brown one near the side. As these are the only two pots in the whole radio, I assume they control the VCO. There ARE Two big upside-down white cylindrical discs with solder at four 90-degree points...Me thinks the VCO is on the UNDERSIDE of this? One is slightly larger than the other (I would assume the larger one is the TX)...I've removed all of the screws on the PC board and the antenna ring but I still cannot locate the actual VCO...

Posted: Wed Apr 11, 2007 1:31 pm
by Max-trac
....The firmware chip is on the logic board.
The VCO is on the RF board on the OTHER side of the radio.
Under the 2nd cover......
Arghhh....
Get a manual....
Or stand by while I take a jpg of the area.....
You DONT'T need to open the PA.
Posted: Thu Apr 12, 2007 12:49 am
by Paramedic606
I don't know what I'd do without you guys! THANK YOU!
Posted: Thu Apr 12, 2007 7:40 am
by Max-trac
OK, on the RF board, (not logic or PA)
Pop off the cover that looks like this;

Posted: Thu Apr 12, 2007 1:24 pm
by Paramedic606
That looks like a piece of paper??? Just kidding...will do!! Thanks!