hello all. I was given a Gray G300 amp because it didn’t work. After removing the case I noticed there were 2 blown ceramic disk cap. These were attached to a diode off the power switch wire before it ran into the transformers. One is completely gone only the legs left and the other has no visible markings on it. I need to know what to caps to put back on that diode. I’ve looked on line for a few days and can not find the info.
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Gray G300 amp blown caps
- Thread starter 200eazy
- Start date
That's a rare problem. I have seen lots of blown electrolytic capacitors but no ceramic disc. Did you look at CBTRICKS.com? The member named Nomad might have information on your unit. He has an amazing stock pile of documents.
Are you sure nobody tried to connect 120 Volts out of the wall into the power leads?
Does the diode "off the power switch" have one side soldered to the ground foil?
Haven't looked inside one of these for years. Don't have any pics in the library here.
Any chance you can snap a pic of this and post it here?
I have a suspicion that your "diode" could be a gray ferrite bead slid over a bare wire, maybe?
73
Does the diode "off the power switch" have one side soldered to the ground foil?
Haven't looked inside one of these for years. Don't have any pics in the library here.
Any chance you can snap a pic of this and post it here?
I have a suspicion that your "diode" could be a gray ferrite bead slid over a bare wire, maybe?
73
That would be the reverse-polarity protection diode. It's there to do nothing when the positive and negative wires have the correct polarity connected to them. If you get positive and negative reversed, this diode serves to pop your fuse and protect the amplifier. The banded end (cathode) connects to the positive power lead wire. The other end goes to ground. Those disc capacitors are only to filter RF signal that can leak out of the amplifier through the power wire. Not sure how to make them blow up.
Except maybe lightning? If it was connected to a power supply plugged into a wall outlet, you can get a surge that comes out of the wall socket, and goes to ground through your amplifier and out the antenna coax shield. Only has to strike a utility pole near the building to do that.
Simply clipping them out won't affect how the amplifier functions on the antenna. And if there is more damage than just the two caps, this won't make it work any better.
Do you have a wattmeter? A dummy load? A general-purpose test meter of some sort?
73
Except maybe lightning? If it was connected to a power supply plugged into a wall outlet, you can get a surge that comes out of the wall socket, and goes to ground through your amplifier and out the antenna coax shield. Only has to strike a utility pole near the building to do that.
Simply clipping them out won't affect how the amplifier functions on the antenna. And if there is more damage than just the two caps, this won't make it work any better.
Do you have a wattmeter? A dummy load? A general-purpose test meter of some sort?
73
I put 2 .01 if back across the diode. Checked it with my meters. Driving it with a 2 watt deadkey it was swinging 100ish on the lowest setting. My current power supply will no supply enough amps to swing it to wide open. Using my ground plane a buddy 12 miles out said it was clean and clear with good modulation.