Motorola Handset HMN1086A HUB Detection

[N3KGD]

Hello all,

I have an MCS2000 installed in my 2008 Chevy Impala. I just recently purchased and installed a (used) Motorola HMN1086A handset. The handset came with the cup holder and of course the handset. I have the cup holder drilled through carpet using 3" screws into the sheet metal below for a secure install. However, it seems that my MCS2000 thinks the handset is off the hook even when it is installed in the cradle. Thus, I always have audio coming from the handset only and never the external speaker.

In theory, when the radio is in handset mode (set through a menu option in the radio) and the mic is "on hook" (in the cradle), audio is supposed to the external speaker. When the handset is picked up and "off hook" (out of the cradle), audio is supposed to be routed to the handset only and the external speaker is muted until the handset is replaced. I've done some research and it appears this handset uses a reed switch which determines if it is in the cradle or not (ie; on/off hook).

When I have the radio in handset mode or not, it still thinks the mic is off hook. However, when I do not have the radio in handset mode, audio comes out both the external speaker and the handset.

My handset did not come with the metal "angled" bracket, just the cradle and handset. I'm wondering if that met bracket is what is needed to make the magnetic connection for the reed switch?

Is there anyway I can make this handset work normally? Am I doing something wrong?

Worst case scenario, I can turn handset mode on when I need to hear and communicate on the handset only, but I'd have to turn it back off to listen to normal traffic. I'm trying to bypass this step so I can use it the normal way described above.

Thoughts anyone?

Thanks!

 

[ramal121]

The handset HUB works better in the vertical position. While horizontal the handset will kinda lever out and sometimes not work. Try moving it around in the cup and see if any angle will engage the HUB.

You can test by getting a larger magnet and sweeping it around the top of the handset (blowing open squelch helps with this). I assume you checked to see if the magnet fell out of the cup.

If all else fails, I've had to replace the hall transistor in the handset to restore HUB operation correctly.

 

[N3KGD]

ramal121, thanks for the reply. There is no magnet on the underside of the cup holder? I thought maybe it may be inside the cradle. I see a white spot underneath the cup holder where it looks like something may have been placed. It is in the same place (on the opposite side) where the top of the handset would rest. However, this is the first time I've dealt with this setup. What does the magnet look like (I mean, in size). Thanks! I will try the magnet direct to handset method.

 

[N3KGD]

So, I managed to find a picture on the net showing the underside of the cradle and well, I can clearly see where a magnet would go and mine doesn't have that. I tried using a fridge magnet directly to the handset and it does close the connection and make the radio think it is on hook. So, I just got to find a strong g enough magnet and secure it underneath the cradle where the top of the handset would rest into the cradle. Thanks for the help on that, it was very much appreciated.

 

[cmdrwill]

Someone stole the magnet.... Maybe the glue failed and the magnet fell out.

There is a reed relay contact in the handset that is hooked to the HUB, 'hang-up' AKA PL disable line, the magnet activates it.

 

[N3KGD]

cmdrwill, thanks for the reply!

Yes guys, there was no magnet underneath the cradle so I went and got one that was the right size and strong enough to trigger the HUB detection in the handset/radio. Everything now works as it should. Stupid, simple fix really. Now I know for the future if I deal with this same thing down the road how to take care of the issue. As I said, this was the first time I've dealt with these handset units so, I figured the magnet was in between the plastic or something? You learn something new everyday! Anyway, thank you all for your assistance!