I have a CM7777 amp that I'm pretty sure isn't working properly (I'm using it in a fringe OTA area with a Winegard HD-8800). ChannelMaster says there's nothing wrong, and that it's too powerful, so I borrowed a 15db amp from a friend of mine. With the 15db amp, I get a great signal. With the CM7777, the signal just disappears. I've also tested it with a 16db attenuator, which should bring the signal to about the same level as the 15db amp, and I still get nothing. I also borrowed a Sedelco DisplayMax 800, and did a couple of full channel scans.
Here's without the amp:
I'm pretty new at this, so I'm not sure what I should see, but that seems like a lot of noise. There's also a huge 15db spike on channel 2, and we don't have a channel 2 around here (and it's a UHF amp).
So, going on the assumption that the amp is bad, I opened it up. The LM7808 regulator measures an output of 8 volts, and the +6v test point measures 7 volts, so those seem to be ok. I am concerned about inductor L8. It looks like it got squished -- at least, I sure don't see any way that that could actually have any inductance, and I suspect that it should look like L7.
Can anyone confirm for me what L8 should look like? If there is indeed a problem with the amp, does anyone have any other ideas of what I can check? I do have access to a signal generator and oscilloscope.