I find the receivers strange back of receivers both say 4200c. The firmware says 4200v ? Both work different. I know on the 4dtv receivers they can change firmware and channel map remotely why not on the 4200. The good thing is both receivers are not receiving trips[hits] so nothing will change.
I am wondering if any services are supporting receiver now ? Now the the schools have switched to DVB ?
The firmware in the 4200 CAN be upgraded via the sat signal. I've posted about this before, but I had my original 4200V upgraded about 12 years ago. I think that most 4200s of all models had a 000030 firmware version. Back in the late 90s, KET (Kentucky Ed. TV) started uploading a nasty firmware version on their transponder that made boat anchors of the receiver, it would happen automatically if you happened to leave your receiver on that mux, but you could stop it from uploading if you switched the power off once it started loading. I think that this firmware had a number something like 000054. Several 4200 owners complained to GI, since they had purchased the expensive (I paid more than $1100 for mine) receiver due to it's ability to view free ZK and FP channels. GI agreed to create a good version of firmware with a number higher than the KET version, so that it would fix the receivers that were killed by the 5400 version , and prevent other receivers from accidently picking up the 5400 versions. The GI techs went to KET, and arranged with 4200 owners to tune in to KET over a weekend. I did this, and watched while my 4200 upgraded from 000030 to 00007C. I think it's the second row in the Diagnostics A screen which shows the firmware version. The first number should be 000030, which was the original firmware version originally installed on the receiver. The last of the firmware numbers is the version currently running. The middle firmware numbers have something to do with the upgrade process, ie I think one indicates that a new firmware download has been detected, another indicates that a download has been initiated, and another indicates the download is complete, and will be installed on next reboot....... or something like that. So if your receiver has anything other than 000030, it has been upgraded.
HOWEVER, the firmware upgrade should not change a B model or C model into a V model, even though it apparently does change the model number listed in the diagnostic screen. Ie my B model, which I bought used, had also been upgraded to the 00007C version, and it was still functioning as a B model, and I know of people with the C version who upgraded, but it didn't change their receiver into a V model. I am pretty confident that the differences in the models are hardware, not firmware, perhaps the daughter board I mentioned, or perhaps some component differences, such as tuner or chipset. THe motherboard itself looks the same, but there are some minor differences in components around the area of the daughterboard.
Anyway, I really suspect that either the motherboard on your one receiver was switched, or perhaps it was sent back to GI for servicing, and they made some hardware changes that upgraded it to a V version. That is assuming that it really can receive the additional modes. I'd suggest that you try tuning in the 3780 NET mux on G28. I think that one is a 29270 Q/I split mode that the 4200V tunes fine, but the 4200B or 4200C should not be able to tune. Ie I think that it is possible that somehow the firmware got corrupted, and the receiver somehow THINKS that it's a 4200V, but isn't really capable of receiving those other SR values. However, it occurred to me that you said that one of your receivers worked, and the other one didn't, so I'm not sure whether the one that gets the whole spectrum of 4200V SRs is the one that works or the one that doesn't work.
In any event, it's an interesting situation
Also, BTW.... I don't use it anymore, but I once programmed one of my JP1 programmable remotes to run the 4200. I basically just altered a device code set for a 4DTV. I think mainly just added that important "TIME" key. I'm sure I still have that JP1 device code around here somewhere if anyone needs a remote for a 4200 and has a programming adapter for JP1 remotes.