Humm ... Have you measured right across the battery terminals at 20V??? That's definitely a defective battery now.??
Good morning Andy,
Thank you for the reply. This unit uses a 12 volt gel battery. Open circuit voltage is at 23 volts. When loaded with a half amp load it will drop to 20 volts. When I connect a new battery the voltage goes to around 18 volts. This would destroy the new battery in a very short time. This is the same voltage right of the bridge rectifier before the regulator circuit. The regulator circuit is powered up at all times and does keep things at 13.6 at all times. when the unit is turned on, the battery gets the 13.6 regulated voltage. The way it behaves is rather odd and cant see it being done by design.
Alan
If that is the case, you have a bad battery.?? It's likely the battery won't power the unit.? Once you confirm that, it's probably the only issue.?? A lot of manufacturers went with a trickle design to charge the nicad, which means that if the battery opened, you would see that high voltage.
Andy Zorca
WJ9J
Hello all,
I have been looking for some older schematics for a Com3 service monitor. I have a earlier design with a serial of 1554 and a RF board?from 1986 as etched in the board. The schematics on repeater builder which is the same ones across?the internet are later that do not match up to what I have mainly for the power supply. Yes, I could remove the RF board and reverse engineer it but would rather not if I don't?have to.
The problem is while doing some maintenance, cleaning the noisy controls and replacing the internal battery I noticed while the unit is powered off there is 23 volts going to the battery. Ouch. When the unit is powered on the voltage goes to 13.6 volts. Voltage throughout the Com3 is at the regulated voltage thank goodness. Going by the schematics available this doesn't?add up and appears virtually impossible to happen. Maybe someone has run into this or can see things differently or even have some schematics?that match this unit.
Thank you in advance for any information.
Alan Bartkowiak N2ZVN
