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Just had an issue that just started tonight. My Anytone 6666 had the carrier just drop almost completely out, but the modulation is working. I can communicate on AM just fine, but if I keep it keyed down, the carrier drops down to almost nothing. I wasn't paying attention to my meter and started...
OK, this is kind of backwards from what everybody usually experiences from a PC. Usually it's PC is interfering with the receive in a radio. In my issue the radio is interfering with the USB in my PC. I have a backlit keyboard and whenever I xmit on SSB the lights go out on my keyboard and I...
I believe the amp to be AB biased. I have ran it on SSB with crystal clear audio reports. I am getting around 700w on SSB just using the Anytone to drive it and my MFJ 891 meter reading the output. The day I used FM, I seen around the same amount of wattage on FM as I was seeing on SSB PEP. So...
I just read back thru it 3 times and have yet to see anywhere you posted that it's a comp cobra 29. (maybe I'm going blind) if it was posted I apologize.
It is a straight 4 pill. I am using an Anytone 6666 to drive it. I was told the maximum deadkey after the amp that I should see with the amp on would be around 100w. I've already had to send the amp back due to popping a transistor and now I'm scared to put the amp back inline with the 1.9swr...
OK, here's my situation. Shockwave antenna with 50ft of lmr-400 into an MFJ meter with a 6ft lmr-400 jumper into the radio, and I know the radio swr may not be perfect but at the radio it is showing a 1.0 swr. I also tested the swr without the radio plugged in with a Nano VNA and swr is around...
I just got one of these myself, It has 8 tubes in it. In the OP's pictures it looks as if his only has 6. What kind of drive should I drive this with. With a 2 watt carrier I can get about 450-500w PEP. Could I hit it with 10w swinging up too 75w?
@nomadradio
Am learning a little as I go. Would love to hear a full explanation as to what actually happens when something such as this happens in an amp. I know it causes high reflect, but why? I mean I have an idea, but it's just an idea. I think it has to do with balancing something within...
I understand what you're saying now. it may not be ground, but it does connect between the 2 sides of the stackpole. In the picture it's C14. The negative side of the mica had come lose.
OK, so I found part of the problem. on top of the stackpole there is a 1000pF stacked mica. The solder connection between one side of the pole and the ground on the stacked mica had broken lose. I soldered the mica back in and the below video is what I get now on the meter.
It has DEI transistors.
@Mustang 131
I don't have a dummy load available, but it does happen with another radio also.
@nomadradio
I did some probing around testing some of the caps while I had it open. I did come across C3 which is very near the input (while using the schematic from cbtricks)...
not sure how to check the impedance on the amp. Is there a way i can do this with a multimeter with the amplifier off? I did check the ohm on C8 and am getting 0.5 with the meter set on 200
Just got this amp for real cheap from someone local. I know it probably had issues, but it was so cheap I couldn't pass it up. So got home and hooked it up on my MFJ-891. It's showing high reflect no matter what setting I have it on. On max setting and with meter set on the 200 watt scale, both...
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