CH721 Remote/ Front Head Swap

[snoopyII]

Anybody ever changed out CH721 heads on a M7300? I attempted to do this, it seems like a pretty straight forward operation similar to a M7100. However... I tried to switch a M7300 front mount scan to a front mount system. Using a known working system head from a remote mount setup. After I installed the system head, fired it up, it went into a continuous boot loop. For testing purposes, I removed the (system head) head and put it back onto the remote mount shell, and hooked the CAN and power connectors to the M73 in question, fired it up and it works fine. It looks like a power feed issue so I'm guessing there is a jumper, mini switch or something that needs to be moved to tell the head where to get the power from. When programming, RPM does not appear to differentiate between remote mount or scan mount pertaining to the CH721 head, it appears to be the same as on the M7100's. Can anybody point me in the right direction?

 

[greenthumb]

Did you update the code in the new control head to be compatible with the code in the MRU?

 

[snoopyII]

That thought crossed my mind. But when I temporarily re-configured the radio to a remote mount setup, I was surprised that it didn't exhibit the same behavior. Unfortunately I don't have ready access to the most current BootApp/ECP/Firmware files.

 

[low3oh]

The CH721 needs to be programmed and told whether it will be a front mount or remote mount CH.

Use this procedure to change the control head’s model information character.
The model information character is the sixth (6th) character in the head’s
12-character EID:
1. If a CAN cable is connected to the control head, disconnect it. The head
cannot be communicating with a radio.
2. Turn the control head off by rotating its on/off/volume control fully
counterclockwise to the off (detent) position.
3. Set a regulated-output DC power supply to 13.6 Vdc and connect it to the
control head’s DC power input connector using DC Power Cable
CA-012365-001 or CA-012616-001.
4. While holding the control head’s “C” preset button fully depressed, turn
the head on by rotating its on/off/volume control clockwise out of the
detent position. When it powers-up, it will indicate “NO MRU” in the
display. Disregard this indication. The head’s test command mode is now
enabled.
5. Using CH-721 Serial Programming Cable CA-104861 (or equivalent),
connect the Personal Computer’s (PC’s) serial port to the DB-9 serial port
connector on the rear panel of the CH-721. If the PC is not equipped with
a DB-9 serial port connector, the use of a suitable adapter is required,
such as USB-to-RS-232 Adapter Cable CN24741-0001.
6. At the PC, start the terminal emulation software such as Windows
HyperTerminal.
7. Configure the terminal emulation software for the respective serial
communication port (e.g., COM1) at 19200 bps, 8 data bits, 1 stop bit, no
parity, and no flow control.
8. Set the terminal emulation software’s function, arrow, and control keys to
act as terminal keys. For HyperTerminal, this is accomplished via the
respective serial port’s Properties dialog box (Settings tab), as illustrated
in Figure 5-3.
9. Set the terminal emulation software for TTY (teletype) emulation. For
HyperTerminal, this is accomplished via the respective serial port’s
Properties dialog box (Settings tab), as illustrated by the left-most dialog
box in Figure 5-3

10. Set the terminal emulation software to echo typed characters locally. For
HyperTerminal, this is accomplished via the respective serial port’s
Properties dialog box (and Settings tab), and ASCII Setup… button, as
illustrated by the right-most dialog box in Figure 5-3.
Figure 5-3: Configuring the Terminal Emulation Software
(e.g., HyperTerminal)
11. While in the terminal emulation software, enable “Caps Lock” by
pressing the respective key on the PC’s keyboard. The control head’s test
command mode only recognizes capital (upper-case) letters.
12. Type the following command to send it to the control head. This is the
“shown EID” command. <Ctrl B> means to hold the keyboard’s “Ctrl”
key down while typing the "B" key. Likewise, <Ctrl C> means to hold the
keyboard’s “Ctrl” key down while typing the "C" key. The space between
the “W” and the “E” must be included, and all letters must be in upper
case.
<Ctrl B>CH-SHW EID<Ctrl C>
The control head will respond with its 12-character EID string, as illustrated in
Figure 5-4. The sixth character in this EID string is the control head’s model
information character that must be changed in a subsequent step. The other
characters within this string cannot be changed.

Table 5-1: Control Head’s Model Information Character
Definitions (6th Character in the 12-Character EID String)
6th
CHARACTER CONTROL HEAD MODEL
5 Front-Mount System Model Control Head
6 Remote-Mount System Model Control Head
7 Front-Mount Scan Model Control Head
8 Remote-Mount Scan Model Control Head
13. Select only the twelve reported EID characters and copy them to the
Windows clipboard.
14. Open a Windows Notepad session and paste the 12-character EID string
into Notepad.
15. Using Table 5-1 as a guide, determine the proper new character for the
control head conversion, for example, if converting a System model
control head from a remote-mount to a front-mount, the correct new
character is 5.
16. In Notepad, change the sixth character of the 12-character EID string to
the proper character. The other characters within this string cannot be
changed!

17. Copy only the 12-character EID string to the Windows clipboard (with
the new 6th character).
18. Within the terminal emulation software, type the following command to
send it to the control head. The space between the “D” and the “S” must
be included, and all letters must be in upper case.
<Ctrl B>CH-LOD SFM<Ctrl C>
<Ctrl B> means to hold the keyboard’s “Ctrl”
key down while pressing the "B" key. Likewise,
<Ctrl C> means to hold the keyboard’s “Ctrl”
key down while pressing the "C" key, then
release both keys before pressing the key for the
next character.
19. Within the terminal emulation software, type the following command to
send it to the control head. This is the “clear EID” command. The space
between the “R” and the “E” must be included, and all letters must be in
upper case.
<Ctrl B>CH-CLR EID<Ctrl C>
The control head will respond with a cleared EID (all 12 characters set to
“F”), as illustrated in Figure 5-5.
Figure 5-5: Clearing the Control Head’s EID (Example)
20. Send the revised EID to the control head by sending it the following
command. Spaces are significant, and “Revised_EID_Characters” is

use a paste function within the terminal emulation software to enter the
EID, before typing the <Ctrl C>:
<Ctrl B>CH-SET EID Revised_EID_Characters<Ctrl C>
CAUTION
Verify the entered string is correct before sending the
<Ctrl C> to the control head. If the string is not correct, press
the Backspace key until the string is erased, type or paste in
the correct string, and then press <Ctrl C>.
An example is shown in the following figure:
Figure 5-6: Sending the Revised EID to the Control Head (Example)
The control head’s EID is now revised to match the new
mounting configuration.
21. Disconnect DC power from the control head, and then disconnect the
serial cable.
22. If performing a front-mount to a remote-mount conversion, connect the radio
to the control head via the CAN link, power-up both units, and verify basic
control head operation. Be sure to terminate the radio’s antenna port with
an appropriate antenna or 50-ohm load.
If performing a remote-mount to a front-mount conversion, continue with the
hardware conversion procedure presented in Section 5.1.2.

 

[low3oh]

information is from the publication marked MM-014494-001

 

[ElroyJetson]

On a slightly related note, I'd like to ask if an M7200 really supports two radios on one control head.

Does anybody know for sure?

 

[snoopyII]

The short answer is no. It does not. (sorry I meant to get back to you on that)

 

[snoopyII]

low3 - thanks for the info, that's exactly what I was looking for.

 

[low3oh]

Sure thing. Shoot me a PM with an email address and i'll see about shooting the whole manual over.

 

[snoopyII]

PM sent.

 

[snoopyII]

Update: the above procedure went as expected, changing of the EID was pretty straight forward. Now I have come across another mystifying problem, after the radio was re-assembled, re-programmed everything seems to work ok...until you turn off the power. When you turn the power back on, the control head seems to revert to the default scan head programming. Interestingly enough, if you plug in the radio to maintenance, the click "jump" causing it to reboot, the scan head programming comes back, (so I know its in there somewhere) until again you turn off the power. I've verified that the EID is set properly. It just cant remember the system control head programming. I've re-installed the original scan head, an it works (and remembers) fine, no problems at all. Bad system head maybe?

 

[ElroyJetson]

I have a related question concerning an M5300 I just picked up.

The radio works and I have my file programmed into it.

The scan button does not put the radio into scan. The scan add/delete rocker does not add or delete talkgroups from the scan list.

Other buttons programmed to valid functions on the keypad section (CH721 system control head) also don't do their functions.

Every button does beep when pressed.

The system rotary (below the volume knob) works.
The group rocker next to it works.

I even saved a control head file first.

I note that you don't have the option to load a control head file like you can with an M7100 or Orion.

I need to test and see if a mic needs to be grounded in order for the radio to scan, but that wouldn't explain why the scan program rocker isn't doing its thing.

Ah, the learning curve...always frustrating at first, but rewarding when you have learned something.


And...never mind. I checked the features list and it's the only EDACS radio I've ever seen that doesn't have EDACS talkgroup scan in it!
I'll have to get that corrected.