Hello, I have put the installation instructions at the link below in PDF. Very sorry for the terrible quality but these were done on a phone in 15 seconds (not near a scanner). If you look at the IF/
Hi Doug, I have a Omni VI+ that needs some repair (a couple unstable LOs) so I had the same question as you did, assuming I can find the problem. I'll be interested to follow the answers. 73 Phil W1P
Hi Malcolm, I have an Omni VI+ and a good cellphone camera. Please contact me off list and I will find the diodes on the board and send you a marked photo. I have the rig open for repairs so it will
Hi Stuart, Also in play is the diode capacitance (related to switching speed of course) and the forward resistance. The BA482 high speed diodes specified on the BPF board have only 1-2 pF capacitance
Hi all, The saga of the deaf Omni VI+ continues. As a reminder, the rig had a repair to the post-mixer amplifier on the BPF/front end board and then I found it was deaf on RX for four low bands (160
Hi all, (I hope someone else someday can make use of this VI+ debugging information..) I'm still troubleshooting my VI+, which you can follow by searching the archive. In particular, I'm still figuri
Hi again, [Forgot to mention: I jumpered across this filter (from D41 to D36) with a 0.01uF capacitor and the receiver came to life on 40 and 30 meters, so this latest problem is definitely in the ba
Hi again, I was hoping to avoid the words "coil rewind" but I guess you're right. Time to break out the magnet wire. Rats. By the way, for posterity, the bandpass filter topology is interesting and b
Hi all, Will KD4FOV and I have been removing what hair we have left trying to troubleshoot a XO/LO board problem for the VI+ under surgery. (See the archives for more detail.) The difficulty has been
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
Hi all, [Sending this to the list instead of directly to Gary and Peter, the usual suspects, in case the results are generally useful.] In the process of buttoning up my repaired (mostly) Omni VI+, I
Hi Gary, Good tip on the filter bypass. If not too much trouble, I'd be most grateful if you measured the IF filter board "gain". While you are in there, it would also be very helpful to check and re
Hi Pete, Hmm - already checked the LO level coming in to the BPF board on connector 26 during an earlier investigation. Depending on band, I got a sine wave with +/- 0.5 to 1.35V using a 1 Mohm input
Hi Pete, Scratch that - forgot a square. The range of LO drive is actually +7 dBm to +15 dBm. The +7 dBm is in fact on 40 meters where I was testing - definitely low. Maybe that increases the convers
Hi Pete, Got a few minutes today. Discovery #1: the post-mixer JFET amplifiers were all shut off because they were not receiving any DC. Culprit was a bad inductor (not a soldering problem) - L39, a