Astro Spectra HHCH for an XTS Convertacom?

[Eaton]

Hi everyone!
I've bought a Convertacom to use it with my XTS5000. Since it was a used item it had nothing with it except for the cradle itself. Now I want to purchase an HHCH (a mic with display and keys) to be able to swithch channels and zones remotely (I need this because the cradle is mounted under the dash and remowing the radio every time you want to switch a channel/zone is very unconvenient).
XTVA HHCHs are rare and expensive. But there are a lot of surplused Astro-Spectra HHCHs (p/n YMN4016) for sale at an affordable price. They look identical but have a D-sub type connector instead of RJ-type needed for an XTVA.
My question is: can I buy an Astro-spectra HHCH and modify it to use with an XTVA (i.e. crimp an RJ plug according to the wire schematic)?

 

[Mars]

Ask Pezking about his experience with the 5K XTVA. A lovely concraption that thing is.

 

[Firecpt809]

Ive had good luck with my XTVA with the HHCH... And no you cant change the plug...looks the same but not the same animal...

 

[motorola_otaku]

Correct, the PLN7737 (XTVA) and the HMN4044 (Astro Spectra) speak slightly different protocols. The PLN7737 was still orderable from MOL, last time I checked.

 

[Alpha]

Actually, they are exactly the same (protocol wise) as they use the same MCU and firmware. The only differences are: 1) The power regulator is wired out, 2) There is a jumper installed to increase mic gain level, and 3) There is a missing transistor switch that affects reset timing. Oh, and of course, the cable ends in an RJ-45 instead of a DB-25. I have documented these changes and other related information here: https://www.p25.ca/threads/1626-Astro-Spectra-AVA-and-HHCH-modification.

The XTS5K works fine in an XTVA with the PLN-7737 HHCH, and my document above explains exactly how to convert the HMN-4044D/E to the PLN-7737. You just don't get the 3rd line of display with the 2-line HHCH display, but otherwise it's quite functional.

 

[Eaton]

Alpha, thank you very much! This is an outstanding guide for converting an AS HHCH to an XTVA HHCH, just the thing I've been looking for! GREAT!!!
The mod doesn't seem difficult so now I'll be looking for the AS HHCH.
The only thing I wanted to ask: thre is an Astro Saber VA in your guide, will the mod work with XTS3/5K VA?

 

[Alpha]

Yes, I mention it sort of in passing, but one of the two "paths" involves changing the HHCH to become an exact replacement for the PLN-7737 which is the right one for the XTVA, also, and then subsequently converting the AVA to work with that model HHCH...

 

[MotFAN]

Hi all!

YMN4016 will work with something other than Astro Spectra? Maybe some convertacoms?

 

[Alpha]

That is the W3 HHCH for the XTL series radios. It's probably very much like the HMN4044, but not having seen one I can't tell if it had any of these "mods" done to it like the PLN-7737. I would assume not, that it's more like the regular Astro Spectra HHCH (HMN4044) until finding out otherwise for certain.

If you read my mod for the AVA-HHCH on the board here, you can take your YMN4016 apart and see which if any of the mods need to be done to it, the same techniques would apply.

 

[MotFAN]

Alpha,

Thanks! I will check your mod.