VXR-7000U can't change "Tx Inh" on transmit frequency

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Hans
Posts: 4
Joined: Thu Nov 08, 2018 5:57 pm

VXR-7000U can't change "Tx Inh" on transmit frequency

Post by Hans » Fri Nov 09, 2018 5:56 pm

Howdy.

We just acquired a used Vertex VXR-7000U and it works great except that I cannot change the transmit frequency on 2 channels. It reads "Tx Inh", which I assume means "Transmit Inhibit". It will let me temporarily enter the frequency but will revert back if I open a menu or write to the radio. I took a peek at the transmit levels by channel but all of them are set the same (0).

- CE27 v1.01 both in dealer mode ("-d) and in user mode
- Firmware v1.19
- Windows 7 64 bit
- Good quality USB cable
- Only channel #2 and channel #3 affected

I can successfully change other settings and channels. I am guessing one of three things:
1) There is a setting that I am missing.
2) The codeplug is corrupt.
3) It was written with a more recent program.

I am working to get v1.08 (international - need wideband). I'm thinking of looking at the codeplug with a hex editor and seeing if there is a discernible pattern to edit it. Anyone have any thoughts, comments, or advice?

Thanks.

Hans
Posts: 4
Joined: Thu Nov 08, 2018 5:57 pm

Re: VXR-7000U can't change "Tx Inh" on transmit frequency

Post by Hans » Fri Nov 16, 2018 9:07 pm

I had to wait for the OP to pass moderation before I could reply to my own thread. 8)

The issue has been resolved. CE27 1.08 didn't fix it. There were no settings that I could find; even in manufacturer mode "-m". It turned out that the codeplug was corrupted. I used a hex editor to fix it. Once I figured out where the channels were stored in the codeplug, it was a pretty easy fix. For anyone else needing to go this route, I'll try to document roughly how I did it.

If it seemed like I was being overly cautious; I was. I did not want to brick the repeater as I do not know how to recover this device should it get bricked by invalid eprom settings.


!!! This is for educational purposes only. I do NOT recommend anyone doing this. If you brick your repeater, that is on you. !!!

I loaded a blank default UHF codeplug and looked for sixteen repeating blocks of data to correspond with the sixteen channels. I made small changes, one by one, to a test copy of the default codeplug. This was to determine which locations within each channel block were relatively safe to change. Then, I settled on a block that was likely the meat of each channel setting. I changed the Tx frequency of channel 1 in the default codeplug and compared that to the unchanged second copy. I flipped back and forth between the two screens until I was very confident that I identified the Tx setting location for channel 1. I took two fresh copies of the default codeplug and changed the last field (can't remember the name) of channel 1 and again compared that against an unchanged copy. I was assuming that the codeplug had a direct linear relationship to the programming screen. I repeated this process on two new files but changing both settings and both channels to verify that there were no interactions between settings; that it was indeed linear and simple. It was. Once I was very confident, I cleared all of the test files from the hex editor and loaded up a backup copy of the codeplug that I had saved from the repeater when we first got it. I opened another copy and saved it as a fix file. I went to channel 1 location in the backup and highlighted from a few bytes before what was determined to be the Tx frequency to what was determined to be the last field. I copied that to the clipboard and pasted it over the complimentary locations in channel 2 and channel 3 in the fix file. I then double checked my work to make sure that I had not added nor deleted any bytes from the fix file. I certainly did not want to create a frame shift. The section copied and pasted from backup looked just like channel 1, 2, and 3 in the fix file. I saved the fix file out and then loaded it into the repeater. All was well after that.

!!! This is for educational purposes only. I do NOT recommend anyone doing this. If you brick your repeater, that is on you. !!!

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