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Using retro servos

Posted: 06 Mar 2019, 09:12
by NeilMac
With the recent conversion of two retro propo set ups I have a few bits left over, battery holders, receivers and of course servos, so the thought occurred, given that many of the S/C set ups are still using age related escapements and as I am now an impoverished pensioner; 'can I use the old servos'?

I didn't want to cut any connectors off at this stage, and as both the MacGregor and Waltron servos have two male and one female connection I was searching around for some wire of the right diameter when I remembered I had an old Skyleader servo in my box of miscellaneous gubbins and as that has an all male connector I was able to rig up a lead that would alloy me to connect it to an FrSky Rx.

Switch on... no smoke, waggle the stick and after a few faltering moves as the servo remembered what it was for... success. I will rig something up to allow me to test the other servos, but they may yet have a function to play, remembering of course that we are flying model aircraft here, so if any of them appear a bit 'iffy', they will remain firmly on the ground.

Anyone else use older servos? Plenty I expect.

Re: Using retro servos

Posted: 06 Mar 2019, 16:01
by RON
Why not make an Arduino servo tester?

nice little project

Ron

Re: Using retro servos

Posted: 06 Mar 2019, 16:43
by NeilMac
Does it involve a lump hammer and a bolster chisel? I'm a dab hand with a lump hammer, I'm pretty good with a blow torch too.

I shall research what is involved Ron; if it requires any form of code it might be a non starter, I have no talent in that particular field.

Re: Using retro servos

Posted: 06 Mar 2019, 17:47
by Stewart
Why not just buy one- there cheap enough :- https://www.ebay.com.au/itm/ESC-Tester- ... xyrjZRxR14

Re: Using retro servos

Posted: 06 Mar 2019, 17:55
by Carl
Here's a link for one I purchased a couple of weeks ago in UK. Works a treat :D

https://www.ebay.co.uk/itm/3CH-Esc-Serv ... 1894090326

Re: Using retro servos

Posted: 06 Mar 2019, 18:18
by NeilMac
Nah, I just bodged up a connection between the Rx and servos and gave them all the go.

The MacGregor MR12's are punchy little blighters. Unfortunately one of the two I have has a terrible case of the jitters, I pulled it to bits but getting cleaner into the feedback pot is pretty difficult without further disassembly.

The two Waltron servos both work fine, if a little on the slow side compared to the MR12 and Futaba 3003's.

I can see me using some of these in future builds, just nothing too quick.

One slight fly in the ointment is the arms, which have a square opening in them... not too many of them about, at least, not new ones.

Re: Using retro servos

Posted: 06 Mar 2019, 18:27
by Shaun
Neil,

Keep your old servos firmly on the ground for demo use; most new servos are reliable and cheap enough. Its just not worth risking old ones in an airframe. Best case they fail and your model hits the deck, re-kitting itself - worst case they fail and hit someone.

Shaun

Re: Using retro servos

Posted: 06 Mar 2019, 18:27
by Shaun
The plastic gears used in many old servos doesn't age well. It's a constant problem for Phils and my museum collection keeping them going on the demo rigs..

Shaun

Re: Using retro servos

Posted: 06 Mar 2019, 18:41
by NeilMac
Shaun wrote: 06 Mar 2019, 18:27 The plastic gears used in many old servos doesn't age well. It;'s a constant problem for Phils and my museum collection keeping them going on the demo rigs..

Shaun
That's a very good point Shaun, and one I'd not thought about.

They can all go back in the box for now, as you say, modern servos are so cheap, no wonder many designs require the builder to cut the mounting lugs off and glue the servos in place.