Seems like I remember an issue something like this during the initial beta testing of Ken's controller... specifically the stamp going wacko and locking the controller. I have a tendancy to agree with Matt's analysis regarding the PNP. You never mentioned a specific type of transmitter... only that you replaced the entire RF deck.
mike -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] Behalf Of DCFluX Sent: Wednesday, April 27, 2005 3:18 PM To: [email protected] Subject: Re: [Repeater-Builder] Mystery: Repeater Problem of the Month Club. Most likely: Audio from the radio which may be biased at 5, 6 or 10volts is not being passed through a non-polarized capacitor to isolate the AC audio from the DC bias and is possibly charging capacitors backwards, causing them to fail/short and pulling the op-amps or audio switches to a DC power bus. Audio switches just go buggo when they see voltage on the lines they are switching that is greater than Vcc. Solve by placing a 1uF non-polar ceramic in the audio line. Possible: Audio is not padded or power surges are getting into the controller audio input line and blowing up the audio switches which may consist of 4051, 4053 or 4066 ICs. To solve this build a simple 1.2V hard clipper from a bridge rectifier. Possible: Bad PNP transistor that is driving a FET that the audio runs through. PNP will slowly "creep" to an on state and mute the audio. I have seen this problem but it was the keying circuit in a MASTR-II base. Would cause the transmitter to key and jam on about 2 minutes after the controllers PTT signal droped. On 4/27/05, vmckever <[EMAIL PROTECTED]> wrote: > > Sounds like you have another radio getting into the controller. Could be > one of the connections i.e. audio cables is resonant at the offending > radio's freq. > > Vincent N6OA > > ----- Original Message ----- > From: "skipp025" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Wednesday, April 27, 2005 2:01 PM > Subject: [Repeater-Builder] Mystery: Repeater Problem of the Month Club. > > > > > > > Mystery: "Repeater Problem of the Month Club". > > > > I just repaired a problem with our 224 Mhz > > Repeater System. Let's see how you fair with > > a guess? > > > > Symptom: Repeater audio would fail, not pass > > the receiver to the transmitter. Controller CW > > and speech audio ok. > > > > Initial Service: Missing Repeat Audio would return > > after re-seating the Link RLC-6 Audio Board chips. > > The repeater would run fine for 1-3 days before the > > problem returned (missing repeat audio) > > > > Second Service: Replaced the RLC-6 board and > > firmware, returned the repeater to service. > > Lasted 1 week before the audio again failed. > > > > 2nd Symptom: Arrived to find the main Controller > > locked in a quasi reseting fault mode. Replaced > > the controller with a spare. Unit lasted about > > 3 days same problems return. > > > > 3rd Trip: Replaced entire Repeater RF deck and Link > > RLC-6 Board with spare (different brand and model) > > Repeater. Controller is still the replaced 2nd unit. > > Everything bench tested for 2 days at the shop. > > Unit failed after 1 day back at the site. > > > > X-Number Service Call: Found 2nd Controller in > > loop fault reset problem (same as the first). > > > > All supply power normal, the same supply operates > > three other repeaters in the same rack. At this point, > > the entire repeater had been swapped out for spares > > and the DC Power Supply tests and works normal > > (operated no where near its max capacity). Stand > > back and scratch your head, then tell me what you > > would do now? > > > > ***** > > > > I found the problem, care to guess what it was? > > > > Your turn > > skipp > > > > ps: Answer in a follow up post: > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
