Help with vintage Nosram

[VintageRacer]

I have, just yesterday, got my son up and running with an freebie Grasshopper and my old Nosram ESC ("Advanced FET Controller") which I posted photos of here http://www.oople.com/forums/showthread.php?t=11263

I've used a Novak lipo LVC and a stick pack lipo and it works ok however

* the car doesn't start up very smoothly, it seems to start at a fairly high speed and snatch at the gear box giving limited speed control, only marginally better than the mechanical ESC we took out.

* there is virtually no brakes and the reverse speed is very slow. The slow reverse I can live with, but the lack of brakes is frustrating.

We still have the 380 size motor in until the 18t pinion arrives and I will put a 540 motor in, could this be part of the problem?

Can anyone remember what the 3 potentiometers are for? 1 is the neutral position adjustment but the other 2 don't appear to do anything. Am I remembering this ESC being better than it actually was or is it dying?

Cheers.

[VintageRacer]

No one?

[imull]

One of the pots will be the top end. Run the motor at full forward and twiddle each of the pots in turn. You should notice a drop in speed, that's when you've adjusted the hi pot higher than full forward. You should then be able to wind it back into where you want. Does that make sense?

At the moment it sounds like high is set right just 'up' from neutral.

I can't remember what the 3rd pot does, maybe brake strength?

[dodgydiy]

my old nosram only has two pots, one neutral point one high point, too old a speedo for torque limiting so i would guess brake strength too, although the brakes did very little anyway compared to newer speedo's

[VintageRacer]

So, the 27t 540 size motor is in and it is much smoother and has better low end control.

I think you are right about the high-end although I don't notice a speed drop at full throttle, only a less than full throttle, and even then, not much change.

Third pot still appears to do nothing and there is little break at either extreme.

I'll have to search through some of my old RRC mags and see if I can get a clue about what they are supposed to do.

[VintageRacer]

I've only gone and found the instructions :drool: Some very primitive hand-drawn diagrams. Also, interestingly branded DNS (Devices Networks and Systems Ltd) which appears to still be in existence in Malvern.

You were right, one is for "forward", or high point, and the other is for brake.

I'll have to have another play now I know which way to turn them.

[VintageRacer]

I think I might have fried it. Maybe LiPo wasn't a good idea on such old electronics.

It was running fine but after a few minutes I noticed it was going slower. Checked it out and the FETs were really hot. Left it for a while to cool except it was really slow after (a little over walking speed).

Oh well....