Acoms Receiver Question

[acprc 1529]

Hi all,

Anybody know if the vintage Acoms ARA-427 4CH receiver is AM or FM? I have one in a Vintage Flakpanzer Gepard Tamiya 1/16 tank and trying to match up a TX. I have a Futaba FP-T4NBL that is 27MHZ AM27 and it doesn't do anything when powered up.

I am guessing that means the ARA-427 is FM27?

[Losi XXT-CR 469]

What country are you in?

Old 27mhz gear used crystals, you need a matching pair in the Rx and Tx. As this allowed multiple people to run at the same time.

[Mouc-RC 644]

Seems that there were two types of ARA-427, as there were two types of AP-427 transmitters that you could pair receivers with:

AM: https://www.ebay.fr/itm/126064452060

FM: https://www.tamiyaclub.com/trades_model.asp?cid=102577

Sorry, it doesn't answer your question, and makes the situation a bit more confused :/

[acprc 1529]

3 hours ago, Losi XXT-CR said:

What country are you in?

Old 27mhz gear used crystals, you need a matching pair in the Rx and Tx. As this allowed multiple people to run at the same time.

UK. I have plenty of crystals I think the issue is which ARA-427 do I have!

[acprc 1529]

1 hour ago, Mouc-RC said:

Seems that there were two types of ARA-427, as there were two types of AP-427 transmitters that you could pair receivers with:

AM: https://www.ebay.fr/itm/126064452060

FM: https://www.tamiyaclub.com/trades_model.asp?cid=102577

Sorry, it doesn't answer your question, and makes the situation a bit more confused :/

Yep,

I am now betting I have a 27Mhz FM Acoms ARA-427 RX and that is why my AM 27MHz Futaba TX isnt working.

[acprc 1529]

So looks like either the RX or my Futaba TX are not working. I remembered that I had a picture of the original TX that should of been with the tank and based on the photos from @Mouc-RC confirmed that the RX is AM as the Acoms TX has the AM details on the top right. I need to check all my 27Mhz AM crystals (and maybe buy a new pair to confirm) but at least I am making progress.

 

[acprc 1529]

and by way of an update I purchased a brand news set of 27Mhz AM crystals. Despite having tried three pairs of crystals previously the new pair worked fine. The Futaba TX is now talking to the Acoms RX. I need to do some servo position swaps however all three servos in the tank were moving (just not with the correct transmitter control).

[Mouc-RC 644]

Good news

In my personal experience, those old AM/FM transmitters + receivers have very different fates, as time goes on. I've had some "quality" Futabas "well stored" in their boxes that just don't to work anymore, some "cheap" Hitec from back in the days, stored half-submerged in nitro-fuel that work perfectly after a good clean...

Old Sanwas seems (to me) to hold up very well.

As a total incompetent guy in electronics, I often wonder why it is so, which component decides to give up without obvious logic... But life is like that