HT1000 connected to RTX-4005B Internal Speaker Not Muting

[slackcc]

Hi all,

I'm attempting to align an HT-1000 and I'm finding that when I have the RKN-4035D cable connected to the HT-1000 and to the RTX-4005B box that the internal speaker on the radio is not muting as it should. I've tried 5 different radios and it is the same on all so I'm guessing it's an issue with either the cable (which seems rather unlikely given that all other functionality works) or the RTX-4005B.

Does anyone know exactly what triggers the HT-1000 to mute the internal audio when connected to an external speaker (i.e. - either a speaker mic or the RTX-4005b)? If I knew that I have a feeling I might be better able to track down the issue.

Any help would be appreciated.

Thanks!

Chris

 

[cmdrwill]

On the test set MT is the correct Audio Out switch position, Audio on the Meter switch.

 

[slackcc]

Thanks,those are the settings I'm using and I'm getting audio out of the 4005B (if I select the speaker) but I'm also still getting audio out of the internal speaker on the radio. So I'm wondering what, electronically, might trigger the internal speaker to mute as I'm guessing whatever that trigger is in the 4005B might be bad.

Thanks,

Chris

 

[ramal121]

A speaker mic grounds Opt Select 1 which I believe will kill the internal speaker. Check to see if the test box is grounding pin 1.

 

[slackcc]

Thanks ramal121 that was very helpful!

After looking through the schematic for the RTX-4005B with that information I was able to determine that in order to properly perform the rated audio test (and all of the audio tests) that the "MT PL" switch needs to be set to "ON", flipping this switch to "ON" grounds Pin 1 (of the Universal connector) which disables the internal speaker of the HT-1000. With that disabled I was able to easily calibrate the audio to the required 3.74Vrms.

Thanks again!

Chris