Hi all, I've just acquired an Omni VI+ with all the filters including the Inrad roofing filters. It is very sensitive as far as RF goes on all bands using a HP 8640B signal generator as a calibrated
Haven't tried TX mode yet because I didn't have a dummy load when I was doing testing. I was hoping there was a quick way to test the meter without that. 73 Phil W1PJE -- -- Phil Erickson phil.ericks
Hi John, Good suggestion - I'll try measuring the coil resistance. I think I might also set up a potentiometer and a battery and try feeding some current in to check needle deflection. (The meter doe
Hi Jim, Thanks - already checked that part out with the S meter unplugged. I could adjust R25 through its full range and see the voltage on a DMM go up and down, so the pot wasn't at a dead spot, but
Hi all, Spent a few minutes more with the VI+. I hooked it to a dummy load and keyed the transmitter in TUNE mode. With the knob on FWD power, the meter did move in sync with the power being drawn fr
Hi all, Thanks very much to this list for the S meter troubleshooting on my Omni VI+. Still finding time to effect that repair but I know now what to do. I have discovered something else though: the
Hi all, Today I had a chance to open the Omni up, desolder the S meter and get the face off. Indeed, the needle was good and stuck mechanically against the internal spring. Gary W0DVN had the answer:
Hi all, Thanks again to this list, I've fixed the earlier S meter problem on my Omni VI+. The remaining problem that persists is low output and input on 12 meters. Initially, Dave K1FK indicated the
Hi Peter, I'll check that next, but I'm a bit mystified if this is the problem since I see there are only 6 LPFs in the bank. So I'm not sure why I would be getting full power on 15 and 10 meters but
Hi Gary, Perfect! Makes sense when I examine the schematic. I should be able to probe around there and see how the 12 meter Y6 crystal is doing and whether it gets through D14. Will check back afterw
Hi all, More investigation has narrowed the problem to the BPF/front end board 81593. We'll use 15 and 10 meters as our "working normally" and 12 meters as "working abnormally" for this discussion: -
Hi Peter, Perfectly happy to not touch the coil slugs! So switching diode check first then resoldering seems to be in order. At least the chassis has plenty of room inside for my fat fingers and for
Hi Gary, Thanks! I'll check the switching diodes first as the easiest thing to remedy before engaging your kind offer of trying a spare board. The temporary 0.01 uF capacitor across the bandpass filt
Hi Gary, The wand detuning technique is one I had not thought of, and is much preferred to touching the coil slugs. If I have to get there, it's non-destructive and I'll definitely try that one as a
Hi all, Thanks for the suggestions. Further investigation on the BPF board using an injected receive tone: - Switching diodes are being correctly biased when 12m is selected (and not biased when it i
Hi all, Success! The "low 12 meter" problem was a cracked solder joint on one of the coils making up the 12m BPF. Tough to spot. Wiggling the coil a bit caused things to jump to life intermittently,
Hi all, If this list will indulge a further curiosity: With my VI+ back together, I measured the filter response of the two SSB filters @ 2nd IF : the default one (2.4 kHz nominal) and the one that I
Hi all, Got it. Barry's link is comprehensive. I will try the noise technique. I have access to a calibrated VNA that I can use for S21 type measurements as well to compare with the simpler noise mea
Hi all, The filter checked out OK using the noise technique, and things were better with my test methodology after a bit of a BFO alignment as well. Still, there is no doubt these rigs are not aging
Hi all, Almost buttoned up my VI+ and making sure now of final things. What is the correct ALC behavior? In CW keyed or TUNE mode, the ALC light is lit no matter what the output power setting is. Hav