Help Converting analog SPECTRA A-5 to A7 etc

[RFI-EMI-GUY]

Motorola Spectra

I have two Motorola Spectra's.

The first is a UHF Model D44KMA7JA5BK (UHF A-5) it has a HLN6094B Command Board and HVN6013A V2.16 (HLN6110B) MLM. This radio was used in a vehicle for a number of years and developed the "capacitor problem". I use it for HAM and GMRS.

15 years back I recapped the UHF A-5 radio with what I felt were appropriate parts, but it has a popping noise when the audio opens and closes. I suspect the command board might have residual traces of electrolyte though it appears clean. So for past 15 years it has been shelved.

The second radio is an 800 MHz model D35KGA5JC7AK (800 MHz C7). it has a HLN6094C Command Board and HVN6026A V6.06 (HLN6160B) MLM.

This 800 MHz C7 radio has operated flawlessly as a desktop monitor until this past year, as it is now functionally obsolete due to P25 system change-out and thus I would like to use it to repair and upgrade the UHF A-5.

What I am seeking to do is:

1) Swap the good HLN6094C Command Board into the UHF A-5 radio to restore its functionality.

2) Swap the 800 MHz C-7 Front control head onto the UHF A-5 radio and upgrade it to an A-7 model.

I am pretty certain I have the "tools" to do this, however it has been so many years since I have programmed these (yes I have a low clock speed DOS workstation).

Can someone outline the procedures I will need to follow to accomplish this? I am certain I will have to record the tuning values from the A-5 radio beforehand in order to get it close to operational. But I am wondering if having the C-7 MLM will streamline the model conversion.

Thanks! Joe K4SAT

 

[rescue161]

Just look up Bit Banging a Spectra for the address changes for the conversions.

 

[jim202]

i guess my post didn't make it the first time.

Here is a link to the repeater-builders site that provides the info your looking for to change control head models. It also has some other good information.

Spectra Hachs and Bit-Banging

The Spectra has been a workhorse for many years and still going strong. I have a number of them that I use on both the VHF and UHF ham bands. Have modified the codeplugs to allow for multi PL and zone operation.

I use the zones for the different regions that I drive into frequently. This way I can program up the repeaters for each of the zones and not have to worry about do I have the channel in the radio or not.

The multi PL selection lets me program up 16 of the more common TX PL tones so that I can change the tone on the fly if I need to.

Contact me if you run into problems and I can probably steer you in the right direction.

 

[RFI-EMI-GUY]

Thanks Jim;

Would it be best to do the board replacement service with the RSS on the target UHF radio, then swap MLM's and bit bang the upgrade MLM to match the UHF radio? I assume this would restore the tuning values to the command board?

After bit banging should I be able to install a UHF codeplug from archive?

It is a bit unclear what happens when I change the frequency band and model of the MLM. At some point there will be a mismatch of the 800 frequencies and C7 model contained in it and the new UHF A5 conventional personality the MLM supports.

Also, is there any cross reference to see what features are gained by using a later MLM version? I am surprised no one has documented that.

 

[cmdrwill]

Best to fix the problem instead of just 'swapping boards' which I do NOT recommend.

Jamming in codeplugs is not recommended either.

You can run either A5, A7, C5 or C7 control heads on the A5 radio.

 

[RFI-EMI-GUY]

I am pretty sure the command board has electrolyte contamination, so swapping a working newer version of command board is what i intend to do.

Please reread my original post.

 

[RFI-EMI-GUY]

Also I want all the button features of the -7 control head. I dont think that will happen with tha A5 radio unless I bit bang the MLM.

 

[cmdrwill]

I still disagree with your assumptions.

 

[RFI-EMI-GUY]

Please explain how I should fix the radio in question and upgrade the model to A7

 

[RFI-EMI-GUY]

I still disagree with your assumptions.

So are you saying I can just attach the C-7 head and the radio will recognize it? I haven't tried that.

 

[cmdrwill]

So are you saying I can just attach the C-7 head and the radio will recognize it? I haven't tried that.

Yes the C7 head is the same circuits as the A and B heads.