For the GE units I have seen, the battery leads came out the large hole in the back of the supply where the DC leads to the fuse mounted on the rear panel emerge. The Repeater-Builder site has the battery backup mod documentation and I downloaded it there. I can look it up if you can't find it.
We had a lead inside a GE supply come loose after we hauled it across the country in a pickup, and ran the repeater off a 20 amp Astron with no problem. It was a 30 watt UHF unit, so the current draw was not too high. One of the larger Astron supplies should run the high power units OK. We repaired the GE supply and it is still in service. There is a Molex plug on the back of the supply, and you have to connect your supply to both the wires in the plug and the two leads to the final amp. The GE supply has a little extra filtering on the low current output and provides a low value fuse in that line. You would be wise to provide a 5 amp fuse in line with the low current Molex connector going into the receiver and exciter area when using a non-GE supply. If the repeater is located in an area where there are people, the buzz from the ferro-resonant transformer will become annoying after a while. And the effeciency of the GE supply is not as good as an Astron. But don't go for a switching supply if you can help it. They are prone to have more problems when operated 24/7 in repeater service. 73 - Jim W5ZIT "Willis M. Hagler" <[EMAIL PROTECTED]> wrote: Hello Jim Thank you for the information. If my GE power supply had the modification installed with a relay to switch to battery power then I would assume there would be some sort of battery terminals on the power supply. Mine doesn't have anything that looks like that so I'm guessing the power supply I have was not built with that mod. Do you (or anybody else) know if it's possible to modify the power supply to add these parts or if anything like this has been done before? Also I am considering not using the GE power supply at all and using a newer one with battery service built in. This is assuming that the GE Master II will run fine off of a regular 13.8v power supply rated for sufficient continuous duty current. If anybody has experience along these lines I'd be interested in hearing about what you've done for power supply that isn't the original GE one. Thanks all, this is a great group of people and I enjoy reading this list! Mark Hagler W7WMH Seattle --- In [email protected], Jim Brown <[EMAIL PROTECTED]> wrote: > > Willis, I have run across two different versions of a factory mod to apply a backup battery to a Mastr II. One has a built in charger and the other uses an external charger. > > The stock GE power supply has a bleeder resistor across the output to keep the voltage in check when lightly loaded, and that has to be disconnected in battery service. The relay in the power supply changes the source over to the battery when the AC power fails and disconnect the bleeder at the same time. It would quickly discharge the battery if it were left connected. > > The filter caps are still in the circuit when the battery is engaged, so there will be no interruption of service when the AC fails. Not even a glitch on the transmitter if it happened to be keyed. > > Here is a link to a recent backup system I installed on a GE Mastr II repeater. It did not have the built in charger, so an outboard charger is used. > > http://sbarcnm.org/forum/index.php?topic=102.0 > > 73 - Jim W5ZIT > > "Willis M. Hagler" <[EMAIL PROTECTED]> wrote: Hello All, > > I have acquired a UHF Mastr II station in great working order. It's > got what appears to be a 65-watt mobile type PA (approx 2" high > heatsink that sticks out the back) so someday I'd like to upgrade that > to a continuous duty model when I run across one. > > In the mean time I am wondering how to adapt a battery backup system > into this unit. I've got the original 30 amp (I think) GE power > supply, where the station gets power from the classic Molex-style > connector and the PA gets power through the large fuse on the rear of > the unit. > > What I don't see anywhere back there is any designated place to hook > up a battery circuit. > > I'm pretty sure there are hundreds of these things across the country > in amateur service and undoubtedly many of you have made some battery > system for this very same setup. If anybody could share how you've > worked in a battery backup and some sort of charging system I'd love > to hear about it. > > Thanks all!! > > Mark Hagler > W7WMH Seattle >
