TOPIC:

I'd like to start by saying that despite searching google and this site like crazy, I can't seem to find any info on a vintage ACOMS system I just purchased. It's missing the battery box and switch, but hopefully I can get it to work by using the Tamiya 5261 BEC for ACOMS that I also just purchased in hopes it is what I need. To be completely honest, I know nothing about ACOMS other than I wanted to pick up a vintage system made by them. I see lots of info on the AP-227, but this one is an AP-272 (2 channel, 72mHz.) and it comes with two AS-1 servos. There's an MRC sticker on the box as well. Any info would be appreciated!

 

 

 
 

IMO, it's a ap227 but in 72 mhz. Strange mrc sticker ( except if it's a model racing car sticker )  because the 72 mhz band was for french market. Like the 26 and 41 mhz.

stingray-63 wrote:

IMO, it's a ap227 but in 72 mhz. Strange mrc sticker ( except if it's a model racing car sticker )  because the 72 mhz band was for french market. Like the 26 and 41 mhz.

I've had 72 mhz here in the states before, I'm even in NJ. The MRC serial number on the sticker matches the radio:

 

GToddC5 wrote:

I'd like to start by saying that despite searching google and this site like crazy, I can't seem to find any info on a vintage ACOMS system I just purchased. It's missing the battery box and switch, but hopefully I can get it to work by using the Tamiya 5261 BEC for ACOMS that I also just purchased in hopes it is what I need. To be completely honest, I know nothing about ACOMS other than I wanted to pick up a vintage system made by them. I see lots of info on the AP-227, but this one is an AP-272 (2 channel, 72mHz.) and it comes with two AS-1 servos. There's an MRC sticker on the box as well. Any info would be appreciated!


 

Interesting find I don't think I've seen one of those before - but it kind of makes sense there would be such a thing ... it could be slightly problematic though. 

The wire colours on the servos are reversed on the "mk.1" & "mk.2" servos (ASA-227 & AS-1, AS-1s, AS-2) - red, black, white rather than the white/red/black that became (a) standard later, "mk.3" servos and on. 
I don't know for sure that the colours for the mk1 & 2 are that red, black, white = +ve, -ve, signal, but it's a pretty good bet.

The BEC unit you have there is for the earliest "mk.3" sets with the ARC RX (I had one my 1st Grasshopper), the next gen ARE RX had BEC onboard  so didn't need anything external - this will have the "wrong" pinout for your ARB RX & might kill it if plugged in without testing & swapping pins over.

72mhz is a perfectly legitimate frequency in the US - in fact I understand it's reserved for RC aircraft and is said to be "illegal" for ground vehicle use, not that I know if anyone ever got prosecuted, or who would do so ... TBH I think the only way you could cause a problem would be to be running your 72mhz buggy on an RC air strip where someone is also using obsolete equipment on their aircraft - can't see it happening

As RC aircraft went pretty much from single channel "control" to 4 channel, a 2-ch 72mhz set would have been almost pointless, apart from the fact that Acoms made very brief foray into RC aircraft - a very basic Cessna 172 Skyhawk kit for 2-channel radios -  & it makes sense they'd want to have a cheap radio to sell with it, one that couldn't be interfered with by ground vehicle TXs.

 


 

The plot thickens, because the frequency on the one coming to me is 72.080 and that isn't listed on this aircraft frequency / channel list:

 

Ah heck, even more info. So much for that theory:

 

 

72mhz was for airplanes to in France.  But my first mk5 techniplus was in 72mhz on my madcap. Like my dealer knee where I drove,  he adviced us to use it. More expensive, but I never had interferences. 
tbh, I thought  the 72 was for france like 26 and 41, and the US used 75mhz. Like on some tamtech  1/24.

GToddC5 wrote:

The plot thickens, because the frequency on the one coming to me is 72.080 and that isn't listed on this aircraft frequency / channel list:
 

 
Frequencies are differents between tx and rx . They are apaired. If you look on graupner quartz it's a badword. It's maybe a more modern pair of crystals.
I think that I have a 72,080 on my mk5.

You're too fast todd.😁😁😁

So, if this thing ends up being for aircraft, should the throttle stick not spring back? Honest question, I really don't know.

Thankfully this was only a 20 dollar lesson, lol, but I still think it's kinda cool.

STILL, there's this which is perplexing given all the info collected so far. Seems I may have a really odd duck:

 

Not for airplanes. You can keep the throttle you want. But for a car, the back spring is needed. Maybe brocken on your tx or removed?