TOPIC:

I don´t know about you but the Acoms RC units never worked for me. I had 3 different sets over a period of 20 years and they have always been faulty. I wonder if there is not a serious integrity problem either with the people who owned the company or in the way they are supposed to be incorporated into the vehicle unit. 
Ultimately I should not have owned any of their gear and this makes me wonder if owning anything made by Tamiya was not a mistake also.

I have several acoms radio sets. Especially a mkV one wich was in my first kit I built and never had any problem with it . And it is still working fine . It was for my madcap.

You need crystals especially for Acoms. Regular "Futaba" one will not work. 
Same for Sanwa/Airtronics, they need Sanwa crystals to work.

Like for graupner crystals.