Vintage electrics

[AndyF]

Hi

I have been trying to get my old procat running. When I plug the battery in the car starts twitching. When running, I can either drive forward or turn, but not both at the same time. If I steer whilst the throttle is open it carries on in a straight line. If I release the throttle it steers, re-apply the throttle and the front wheel remain at the same angle.

It has an old 17T single motor, speedmaster esc and a futaba receiver all around 18 years old!!!

The question is; Is it my receiver, transmitter or esc thats at fault? Any ideas?

Andy

[Mike Hudson]

servo

[Gayo]

Servo and esc plugs may be touching each other into the receiver box, if you know what I mean. I would definitely check that first.

Good luck!

[Col]

This sounds like my entirely modern car does when the battery's are flat. Are your cells old? Maybe they no longer have enouge volts (or is it amps) to do all this at once?

[traffman]

Correct me if im wrong but something in my head thinks its the battery eliminator circuitry that may be at fault.

Ha s the speedo got the reverse relay or is it the fwds only ?

[niggs98]

depends on the speedmaster that you have, if its a silver star then it is forwards and reverse, if its a goldstar then its forwards only. if there is no stickers on it to say either way thn post a pic and i will let you know

[AndyF]

Hi,

Thanks for the replys.

The esc is the silverstar with reverse relays. I have checked the esc and servo wires and all looks well.

I intially tried it with some old phil greeno 1700mah cells that I had that were 18 years old. Of course i didn't even expect the car to move let alone anything else. They actually gave me about 3 - 4 mins of run time. I then bought some second hand 4200mah cells which i charged with my old thermal cut off charger. I set it to cut off at a modest 40C. When I checked the voltage level on the cells they were up over 8V so I figured they had charged ok.

Same problem however. The car is very jittery (the forward and reverse relay clicks and the car give little start back and forth). The steering servo can also be heard to make straining noises. When I push the stick forward the car sets off but wont turn until I let go off the throttle. If during the turn I put the throttle back on again the steering remains at the same angle until I release the throttle. All very strange.

[Oscar]

Have you thought about a dry joint on the power wires? corrosion could be a factor after such a length of time, or maybe even you have a break in one of the cables?

[MiniGaz]

once upon a time when i used to race, i had a similar problem in that when the car was stationary it would be very twitchy, when i opened the throttle the car would launch off down the track then take an immediate right turn into an immovable object usually after about ten yards.
turns out i had a knackered set of crystals and after a swap to another set all was ok, just to check i put the dead ones back in and sure enough it did the same thing.
might be something to look at if it's vintage leccies your trying to suss out./

[JBL]

If you are worried about your speedo not working fully, you can still send it to Speedmaster who are still in business. Please check www.speedmaster.co.uk for more details.

[AndyF]

Thanks guys.

Fixed it! I was looking in the wrong place.

It was the transmitter at fault. The wire attached to the bottom of the telescopic arial was loose. Tightened it up and normal service resumed.