Batboard

I have a UHF BPR40 that has no PL or DPL encode. It also has poor receive sensitivity. It takes 6.5 microvolts to decode and have audio and audio drops out at 4.3 microvolts. Also, squelch is open on CSQ. I have not adjusted squelch pot. I have inspected both sides of board for physical and liquid damage. I have not checked IF filters yet. I did reprogram with no help on problems.

Poor receive sensitivity brings to mind the recent FSB describing defective antennas that the OEM supplied with the BPR40s. The antenna stud was too long causing a direct short to ground inside the portable when the antenna was installed. However, this may not apply since you may have checked sensitivity with the BNC adapter installed and using a service monitor. I've never seen information on the availability of a schematic, and there's nothing in the service manual that I have on the BPR. You may have to do a back cover kit replacement if there's no schematic information available.

I have a SM with schematic for the MagOne radios.

For a $150 radio it doesn't even pay to send it to the Depot. If it isn't readily apparent, replace it.

Andreas,

If you have a service manual and schematic how about scanning it and making it available to others.

Regards,

Allen

arlojanis wrote:I have a UHF BPR40 that has no PL or DPL encode. It also has poor receive sensitivity. It takes 6.5 microvolts to decode and have audio and audio drops out at 4.3 microvolts. Also, squelch is open on CSQ. I have not adjusted squelch pot. I have inspected both sides of board for physical and liquid damage. I have not checked IF filters yet. I did reprogram with no help on problems.

Sounds like the reference oscillator is way off...it's the timing base for everything & will cause many issues if it's drifted a few KHz.

The tone level pot was open. PL and DPL are both controlled by the same pot. I adjusted wide and narrow squelch pots and squelch is now closed. I still have audio problems and sensitivity problem.

if it is a receive problem when programeed for narow band but works in wide band, motorola knows of a crystal filter problem in early series,and has new filters.