Hey Scott.
Thanks for writing back. You did some work for me not too long ago. I sent up a spectra-tac receiver that you retuned for me while Kevin was busy somewhere. We swapped the vibrasponder tone element too. I needed 131.8, and you took what was in it and put that one back in.. Remember? Anyhoo... I got this unit about a year ago, and it looked brand new.. Not a scratch on it. Still had that new smell too. I employed it as a IRLP link radio. It's a 10w unit. I'd often try to operate the IRLP node and it would not respond. Turned out to be this unit's receiver. I opened it up last nite. Looked totally virgin inside. I cleaned the connectors where the boards(top and bottom) attach to the chassis. I had to take the lid off what I'm assuming is the VCO compartment to get at a couple of screws to lift the board. It's the shiny lid that presses down over a couple of sections inside the radio, correct? I'll open it up again this evening and take a measurement at the test point you indicated. I'll assume I don't need a signal present to make this measurement. Might be good if you could give me a pointer to location of the RX VCO coil too, so I can tweak if it's out of spec.. Is it labeled? What voltage would be considered acceptable? 7 +- 2v or so??? It really doesn't seem temperature related. The unit operates in a climate controlled room. I may send it up to you for a look if I can't make any headway, if you work on these... 73s, and thanks again for writing back. Russ From: Scott Zimmerman [mailto:[EMAIL PROTECTED] Sent: Wednesday, October 03, 2007 2:26 PM To: [email protected] Subject: Re: [Repeater-Builder] Help with Motorola Radius M120 - Intermittent Recieve Russ, If the receive is intermittent, your problem is likely NOT the LO being off-frequency. An LO that was off would rear its head as sounding off frequency or poor sensitivity. I have had some problems with the LO crystals drifting as of late, but I don't think that is your problem from the description you provided. At any rate, the second LO crystal frequency is 44.645 NOT 45.645. The IF frequency is 45.10, so 45.100 - 44.645 = 455KHz. It sounds to me like you might have a broken/cracked solder joint somewhere inside the radio or that the Rx VCO is going out of lock. Does it seem to be temperature related? If so, that would lead more toward the VCO. You can open the radio and VCO compartment and see what the voltage is on the test point marked "SL." It should be around 7v or so. If not, you can adjust the Rx VCO coil to get it more in-line where it needs to be. Good luck, Scott Scott Zimmerman Amateur Radio Call N3XCC 612 Barnett Rd Boswell, PA 15531 ----- Original Message ----- From: "russcrisp" <[EMAIL PROTECTED] <mailto:rcrisp%40gmail.com> > To: <[email protected] <mailto:Repeater-Builder%40yahoogroups.com> > Sent: Wednesday, October 03, 2007 1:44 PM Subject: [Repeater-Builder] Help with Motorola Radius M120 - Intermittent Recieve >I have a Moto M120 UHF that has intermittent receive. Doesn't work more > than it does.. A friend suggested that I count the Second LO, and make > sure it's at 45.645 Mhz. I have no service documentation on this model, > so rather than poke all around looking for something that may not be > there, I thought I ask the group here for assistance. > > Does anyone have experience with the M120? Is this indeed the correct > setting for the second LO for a UHF radio? 438-470.. Where is the > proper place to attach a counter to measure this? > > Any help would be greatly appreciated. This radio is used in a link. > > Best regards, > Russ Crisp > K4RCC > > > > > > > Yahoo! Groups Links > > > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.488 / Virus Database: 269.14.0/1046 - Release Date: 10/3/2007 > 10:08 AM > >
