KO PROPO PS-87 FET Servo
 

Hi,
Is anyone out there running a vintage PS-87 servo using Lipo power?

This servo has a blue wire that you connect directly to the battery positive, but the specs on the servo say this should be 7.2V, I'm wondering if the 8.4V from the Lipo would be a problem?

I suspect that back in the day a fully peaked pack of SCRs were probably way over 7.2V anyway, but my memory is not that good and all my old cells seam to have died!

This servo is a little low on torque by modern standards, but looks fast enough, and I'm hoping that if it stood up to the abuse I gave it as a teenager, it might survive a bit of running in my recently restored YZ10.

I would appreciate hearing of any recent experience of running one of these servos.

Thanks.

Nigel,

I can't say from direct experience of your particular servo, but my ProCat is running an older 2000 series KO servo with the blue 'hot-wire' lead, which is connected directly to the + battery terminal on my ESC. This servo is probably mid-90s era so long before the invention of the LiPo battery, but has been working faultlessly in my LiPo equipped buggy :thumbsup:

From memory a pack of old-style Nimhs could peak at 9v - of course this would drop as soon at the charge is stopped but I'm sure your servo would be ok being powered by an 8.4v LiPo ;-)

Servo
 

2nd that , I was running my old 90's blue wire ko servo with a lipo and it was fine , no problem at all.

i still use ps1001's and they are fine with lipo, not tried the older ps87, if worried try putting a very low value resistor inline on the blue wire with your choke, to slightly limit the peak current, as thats what'll kill the fets, not the voltage