Hi Eric .Two radios here are not working properly and I found in one that the 8meg crystal was 2.4khz off frequency and in the other radio there is no 8 megs at all.so this should explain the radios not working .on a good radio the ctcss was 131.8 and the crystal was very near to the 8.2944mhz .On the service monitor the 131 was stable but the .8 was flicking up and down a little but it never altered from 131hz Thank You, Ian Wells, Kerinvale Comaudio, 361 Camboon Road.Biloela.4715 Ph 0749922449 or 0409159932 or 0749922574 www.kerinvalecomaudio.com.au -------Original Message------- From: Eric Lemmon Date: 18/10/2009 09:16:09 To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Maxon sm4450sc Ian,
The CTCSS tones are derived from the timing of ASIC IC107, and are independent of the carrier frequency control circuit. Use your service monitor to "sniff" around the CPU to see if the clock is running at or very close to 8.2944 MHz. If it is way off, you'll need to replace the X1 crystal since there is no adjustment. Crystal X1 is type HC-184, part number 260-862-6Z. 73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups com] On Behalf Of kerinvale Sent: Saturday, October 17, 2009 2:36 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Maxon sm4450sc Hi guys .Has anyone come across the ctcss frequency being a little off frequency on a maxon sm4450 I.e. For 123 Hz the radio produces 122.5hz or below is there anyway to make the radio produce the exact programmed Hz Thank You, Ian Wells
