Great troubleshooting tale. Glad you didn't want to kill a working instrument to get a part. I wonder if it would be possible to substitute something like a Mini-circuits LK-3000+ in place of the HP hybrid??
Unfortunately I don't think you can. If you look at U4 on SS17A it has an on/off control. There is a schematic of what might be on the hybrid so you might be able to create a small discrete board replacement. Alternatively there may be a controllable doubled that you could cobble into place.
@@tgsoapbox 6 years ago but I give it a shot... According to your video's it looks like we're running into the same issues with the HP gear. You wouldn't have found a source for that doubler? I just can't find one and I hate the idea of buying and scavenging a 8901.😬 Great Video btw! Cheers
@@McZaustria I never really looked into it very much - I managed to get a replacement board from a HPAK group member that addressed the issue so I was lucky that I didn't need to - At this stage you're probably going to have to part a unit out to get a replacement or try to create a component from something more modern to fit in.
@@tgsoapbox Thank you for responding. The problem I have is on the 8902A. Specifically, the machine 8902A measured at 10 MHz frequency; 20 MHz; 1.3 GHz. But at 125.6 MHz, 700 MHz the machine shows 4 dashes. Can you please advise me? Thank you very much
@@KhuêNguyễn-p7w I replied to your other comment on this - I would start by testing the front-end amp (U1) to ensure that it is working correctly - If it is then you'll need to follow the signal path through to see if you can find the issue - The numbers your mentioning don't ring a bell with me as key points in the frequency range unfortunately.
Great troubleshooting tale. Glad you didn't want to kill a working instrument to get a part.
I wonder if it would be possible to substitute something like a Mini-circuits LK-3000+ in place of the HP hybrid??
Unfortunately I don't think you can. If you look at U4 on SS17A it has an on/off control. There is a schematic of what might be on the hybrid so you might be able to create a small discrete board replacement.
Alternatively there may be a controllable doubled that you could cobble into place.
@@tgsoapbox 6 years ago but I give it a shot... According to your video's it looks like we're running into the same issues with the HP gear. You wouldn't have found a source for that doubler? I just can't find one and I hate the idea of buying and scavenging a 8901.😬 Great Video btw! Cheers
@@McZaustria I never really looked into it very much - I managed to get a replacement board from a HPAK group member that addressed the issue so I was lucky that I didn't need to - At this stage you're probably going to have to part a unit out to get a replacement or try to create a component from something more modern to fit in.
@@tgsoapbox Thanks, I had a feeling you'd say that 😁.
Great videos on the 432 meter. Looking forward to more content.
Cheers!
You held me. 8902a measurement frequence indicator - - - -. You advice me? Thank you
Happy to try and help but I don't understand what the problem you're having is. Can you try explaining it again?
@@tgsoapbox Thank you for responding. The problem I have is on the 8902A. Specifically, the machine 8902A measured at 10 MHz frequency; 20 MHz; 1.3 GHz. But at 125.6 MHz, 700 MHz the machine shows 4 dashes. Can you please advise me? Thank you very much
@@KhuêNguyễn-p7w I replied to your other comment on this - I would start by testing the front-end amp (U1) to ensure that it is working correctly - If it is then you'll need to follow the signal path through to see if you can find the issue - The numbers your mentioning don't ring a bell with me as key points in the frequency range unfortunately.