M7100 Ignition Sense

[KG5HHS]

Hello everyone,
I am installing a VHF P25 M7100 in my crown vic. I have it all connected and it is working fine, except it will not turn off. I have the yellow wire from the control head fused and connected to a charge guard that shuts off after 10 seconds, however the radio is still not shutting off. I also tried turning the volume knob all the way to the left, the radio reads "Vol=Off" but the radio does not power down. I remember reading a thread a while back about a dip switch, but can not find it. Is this something I can fix in Programmer or by a dip switch?

 

[emtLarmy15]

There’s a switch under one of the panels.

 

[KG5HHS]

It took me forever to find the little switch, but I got it. it's working perfectly now.

 

[kb4cvn]

M7100 Ignition Sense Voltage Spike Issue & Fix

[FONT=&quot]I STRONGLY suggest putting a noise filter in the ignition sense (yellow) wire on any M7100 radio. Back in the mid-2000's there was an issue with the M7100's with a short NEGATIVE voltage spike (>100 V) occurred in some vehicles, when the vehicle was started, destroying the MOSFET ignition sense device in the M7100's. The usual symptom observed by the user is the radio will not turn-off.
[/FONT] See Image.
[FONT=&quot]
[/FONT]BACKGROUND:
[FONT=&quot]In the Orion radios, this switching function was handled by an [analog] relay (K601), which was "upgraded" to a solid-state device in the M7100's. [/FONT]


[FONT=&quot]First observed in February 2008, the spike was only detectable on a storage Oscilloscope. Too fast for the VOM, DVM, VTVM to detect. The preventative fix was to place an inexpensive 5 Amp (or less) DC Noise Filter in the [Yellow Wire] Ignition Sense circuit. This recommendation was implemented in the M7100’s Installation Manual [MM102342V1], and an extract of this page is attached below as a PDF.[/FONT]

[FONT=&quot]For radios already damaged, replacement of the Mosfet is the only remedy.[/FONT]

 

[KG5HHS]

[FONT=&quot]I STRONGLY suggest putting a noise filter in the ignition sense (yellow) wire on any M7100 radio. Back in the mid-2000's there was an issue with the M7100's with a short NEGATIVE voltage spike (>100 V) occurred in some vehicles, when the vehicle was started, destroying the MOSFET ignition sense device in the M7100's. The usual symptom observed by the user is the radio will not turn-off.
[/FONT] See Image.
[FONT=&quot]
[/FONT]BACKGROUND:
[FONT=&quot]In the Orion radios, this switching function was handled by an [analog] relay (K601), which was "upgraded" to a solid-state device in the M7100's. [/FONT]


[FONT=&quot]First observed in February 2008, the spike was only detectable on a storage Oscilloscope. Too fast for the VOM, DVM, VTVM to detect. The preventative fix was to place an inexpensive 5 Amp (or less) DC Noise Filter in the [Yellow Wire] Ignition Sense circuit. This recommendation was implemented in the M7100’s Installation Manual [MM102342V1], and an extract of this page is attached below as a PDF.[/FONT]

[FONT=&quot]For radios already damaged, replacement of the Mosfet is the only remedy.[/FONT]

I think it maybe too late for mine... I have the yellow wire fused (3Amp) and ran to a charge guard, Which does turn on and off properly when the charge guard shuts off, but it will not shut off when I turn the volume knob to the off position. It still just shows "VOL=OFF".

 

[kb4cvn]

I think it maybe too late for mine...

Oh boy.

 

[kb4cvn]

Ignition Sense Lead Fuse Rating

OH, one other tid-bit....


The manuals and parts list for the Orion, J725m and M7100 have always had an error.


The IGNITION SENSE FUSE is listed as a 3.0 Amp item. This is a typo. It should read 0.3 Amp.


I brought it to the attention of the Product Manager one day. He refused to 'fix' it, as he "did not want to spend the money to revise everything" !!!