[Repeater-Builder] R100 stays keyed up
Hi all, I have a Motorola R100 2-10w UHF repeater on the bench. It was working fine (pulled from of working service) until a frequency programming change (only 25 kHz). Now it stays keyed unless I change the repeater disable switch on the board. It does pass receiver audio normally but the repeater never drops the carrier. In fact it keys up immediately upon power on. I disconnected the receiver to make sure it nothing was causing the transmitter to trigger. I am not too familiar with troubleshooting these repeaters as they have always worked well in the past. Am I looking at a codeplug corruption issue or is it a coincidental hardware issue. Any tips or sharing of common failures appreciated. Thanks. - Rob
Re: [Repeater-Builder] R100 stays keyed up
I'd start at http://www.repeater-builder.com/motorola/r100/r100-index.html and download the service manual. Start at the transmitter PTT line and see if it's pulled low. If it is, backtrack on the schematic / transmitter board and see what's doing it. If it's not, then I'd look at the codeplug. Mike WA6ILQ At 08:52 AM 12/30/09, you wrote: Hi all, I have a Motorola R100 2-10w UHF repeater on the bench. It was working fine (pulled from of working service) until a frequency programming change (only 25 kHz). Now it stays keyed unless I change the repeater disable switch on the board. It does pass receiver audio normally but the repeater never drops the carrier. In fact it keys up immediately upon power on. I disconnected the receiver to make sure it nothing was causing the transmitter to trigger. I am not too familiar with troubleshooting these repeaters as they have always worked well in the past. Am I looking at a codeplug corruption issue or is it a coincidental hardware issue. Any tips or sharing of common failures appreciated. Thanks. - Rob Yahoo! Groups Links
Re: [Repeater-Builder] R100 stays keyed up
Some repeaters have the option of letting the VCO run continuiously and they key the power amp circuits, The benefit is the PTT rise time goes from 50-100mS down to like 4mS. The disadvatage is that any radios in close proximity to the repeater hear the VCO running due to leakage, is that the case here? Do you actually have full power out of the repeater all the time? Also you might try removing the programing cable from the repeater as it appears to share the PTT line.
Re: [Repeater-Builder] R100 stays keyed up
DCFluX wrote: Some repeaters have the option of letting the VCO run continuiously and they key the power amp circuits, The benefit is the PTT rise time goes from 50-100mS down to like 4mS. The disadvatage is that any radios in close proximity to the repeater hear the VCO running due to leakage, is that the case here? Do you actually have full power out of the repeater all the time? Also you might try removing the programing cable from the repeater as it appears to share the PTT line. It is full output (10W) as measured on the Telewave meter. I did remove the programming cable when I did the power cycling. Thanks, - Rob
