Yep, I have one of these things. Went through and did a recap, found several bad caps that looked OK from the top, but the leads were an odd shade of green. Also had a problem with the 8 volt regulator, but a quick replacement and that's sorted now. Then found a broken coax jumper that went between the transmit board and the SWR/antenna switch board. I had a bit of coax from an SDR kit (cheap dongle, cable, rabbit ears) that I hacked up to replace that.
It's been modded for extra channels at some point in the past with a small PC board that has the two MC14008 adders on it that were moved from the PLL baord, and an extra chip (MC14081) and a transistor (2N3904) plus a few other components. Had a problem with the channels sort of jumping back and forth that I traced to a wire that had broken off the mod board.
Now for the weirdness. I went through and started checking the PLL programming, because all channels are 10kHz down from where they should be on receive. And it tracks across all 40 channels. Also, it transmits on a different frequency than it receives on, and it's a different frequency for all 40 channels that seems to follow the same 40 channel pattern. When checking the PLL N-Codes against the service manual, I found that on receive the PLL was getting the transmit N-Code (the PLL gets shifted up 455 KHz between RX and TX) and it's the correct one for that channel. On transmit, the PLL is getting an N-Code that is the same as receive +91. So it's still doing the 455 kHz shift up on transmit that it's supposed to, it's just giving a weird result.
At this point I think there's a problem on the mod board with one of the adders or the other chip. That or the darn thing was wired wrong and has always been messed up. I'm pretty sure the microcontroller is OK, but I need to figure out if it's actually putting out the codes it's supposed to. It probably is, since it seems to put out the correct patterns for tuning 40 channels with the adders doing the rest of the work.
I know the ARF 2001 is considered "rare" (although some consider it junk), but I was wondering if anyone has ever had anything like the problem mentioned above. The mod board seems to have been a popular option as I have a printed page documenting it, sort of, although I can't find a source for that. But it's enough to tell me that someone else has probably done this mod or bought a unit with it installed and may have seen this or a similar problem.
Thanks for reading my stream of consciousness post. I'll post pics of any part of the radio if you all think it will help.
TL;DR: Fancy radio broken, but not as bad as it used to be.
It's been modded for extra channels at some point in the past with a small PC board that has the two MC14008 adders on it that were moved from the PLL baord, and an extra chip (MC14081) and a transistor (2N3904) plus a few other components. Had a problem with the channels sort of jumping back and forth that I traced to a wire that had broken off the mod board.
Now for the weirdness. I went through and started checking the PLL programming, because all channels are 10kHz down from where they should be on receive. And it tracks across all 40 channels. Also, it transmits on a different frequency than it receives on, and it's a different frequency for all 40 channels that seems to follow the same 40 channel pattern. When checking the PLL N-Codes against the service manual, I found that on receive the PLL was getting the transmit N-Code (the PLL gets shifted up 455 KHz between RX and TX) and it's the correct one for that channel. On transmit, the PLL is getting an N-Code that is the same as receive +91. So it's still doing the 455 kHz shift up on transmit that it's supposed to, it's just giving a weird result.
At this point I think there's a problem on the mod board with one of the adders or the other chip. That or the darn thing was wired wrong and has always been messed up. I'm pretty sure the microcontroller is OK, but I need to figure out if it's actually putting out the codes it's supposed to. It probably is, since it seems to put out the correct patterns for tuning 40 channels with the adders doing the rest of the work.
I know the ARF 2001 is considered "rare" (although some consider it junk), but I was wondering if anyone has ever had anything like the problem mentioned above. The mod board seems to have been a popular option as I have a printed page documenting it, sort of, although I can't find a source for that. But it's enough to tell me that someone else has probably done this mod or bought a unit with it installed and may have seen this or a similar problem.
Thanks for reading my stream of consciousness post. I'll post pics of any part of the radio if you all think it will help.
TL;DR: Fancy radio broken, but not as bad as it used to be.