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Matt kd4pbs · 2nd Apr 2021, 7:54 pm

Sorry guys - I've been swamped with some other projects as of late, and have not had a chance to visit you all. That's great news, Lex! I will certainly look there as well, and it sounds as if you saw the exact same thing with the 30MHz amp as I did. I finally called it a day on that one and moved on; I'm sure it's working fine. If something were bad, I'd see it at DC, or wouldn't be able to control the level through the amp, or would see lots of loss.
In the meantime, I did get some time to spend with the SpecAn, and got all of my extender bits in. The video game extender cables work, more or less. The leads are so long that it causes problems... the cabling is all unshielded conductors and are almost a meter long! I'll need to shorten those a bunch, but I actually do enjoy there being cables instead of a card. It makes it easy to lay the board on the table and work from there. For the smaller card edge cards, I did find an extender card. As such, I was able to go through part of the calibration - namely most of the stuff in the display chassis. What I found was that there were quite a few noisy trimmer pots, and I imagine this was causing some of my lock up problems. So far, between that calibration and finding a broken wire on that little YIG driver piggyback board modification, I am not having the lockup issues that I had before. Only one remains; with a signal in it or not, if I select a CF of 50.050MHz and a span of 500KHz, it freezes. I can do it all day long at 50MHz, or 50.1MHz. Even if I dial it into 50.050, it freezes. I haven't spun through the range yet to see if it freezes anyplace else. Quite aggravating.
I will certainly look closely at that filter section. I hope it is that easy.

2nd Apr 2021, 7:54 pm	#161
Matt kd4pbs Tetrode Join Date: Mar 2021 Location: Raleigh, North Carolina, USA. Posts: 62	Re: Spectrum Analyser TR4172 Sorry guys - I've been swamped with some other projects as of late, and have not had a chance to visit you all. That's great news, Lex! I will certainly look there as well, and it sounds as if you saw the exact same thing with the 30MHz amp as I did. I finally called it a day on that one and moved on; I'm sure it's working fine. If something were bad, I'd see it at DC, or wouldn't be able to control the level through the amp, or would see lots of loss. In the meantime, I did get some time to spend with the SpecAn, and got all of my extender bits in. The video game extender cables work, more or less. The leads are so long that it causes problems... the cabling is all unshielded conductors and are almost a meter long! I'll need to shorten those a bunch, but I actually do enjoy there being cables instead of a card. It makes it easy to lay the board on the table and work from there. For the smaller card edge cards, I did find an extender card. As such, I was able to go through part of the calibration - namely most of the stuff in the display chassis. What I found was that there were quite a few noisy trimmer pots, and I imagine this was causing some of my lock up problems. So far, between that calibration and finding a broken wire on that little YIG driver piggyback board modification, I am not having the lockup issues that I had before. Only one remains; with a signal in it or not, if I select a CF of 50.050MHz and a span of 500KHz, it freezes. I can do it all day long at 50MHz, or 50.1MHz. Even if I dial it into 50.050, it freezes. I haven't spun through the range yet to see if it freezes anyplace else. Quite aggravating. I will certainly look closely at that filter section. I hope it is that easy.