Speedmaster Silver Star Ultra 7.2v Mod

[TWINSET]

DISCLAIMER:

• This mod is not in any way associated with, endorsed or recommended by Speedmaster
  
• I have no idea of any long term damage this mod may do to any equipment
  
• I do not recommend you try this mod, it's just an experiment, which is working at the minute
  

I've long been a fan of Speedmaster Silver Star Ultra (SSU) ESCs, but just lately have noticed that, on twin servo clods, the servos struggle to steer the truck, either when stationary or moving slowly.

In the latest vid, you can see the rear servo stuttering, at around 1:20 - 1:22 http://www.tamiyaclub.com/moviecomment.asp...568&uid=169

At faster speeds, the rear steering was heavily influenced by the general direction of travel - kinda like a supermarket trolley's castors.

There were discussions about adding a receiver battery pack (as per nitro cars), but I wasn't keen on having yet another battery pack to charge.

Anyway, it transpires the SSU only outputs 5v to the receiver (and in turn, the servos)

So, made a couple of calls to Speedmaster, basically seeing if there was anyway to 'tamper' with their ESC to feed 7.2v to the receiver;

Turns out, there's full battery power (7.2v in my case) going through the switch loop, so the theory was the wiring could be 'tapped in to' using the red wire from the receiver plug.

This wasn't a problem, as my receiver can handle 9.6v, and the servos are good for 7.2v

The mod would involve cutting the red wire, and splicing it to the blue wire - by stripping a section of insulation and soldering the red wire to the exposed 'blue' wire, and insulating or removing the rest of the cut red wire.

I didn't fully grasp the concept on the first call, and actually cut the blue wire, thus rendering the switch redundant, and the whole thing not working.

With nothing to lose, I then cut the yellow switch wire and tried that on the red wire - I got steering!

So, I then twisted the red, blue and yellow wires together, and voila!! everything worked again

Here's a quick artists impression of the layout;

Now, this was generally untidy, with cut wires all over the place, so I had a tidy-up.

The plan was to attach the red wire straight to the circuit board (PCB) and get rid of the blue and yellow switch wires, along with the cut bit of the red wire.

I've already modified two or three SSUs in the past by soldering longer motor wires to the PCB, so wasn't too worried aboutcracking this one open for a play.

Here's a 'stock' Silver Star

Receiver wires go off to the left of pic, and to the right you have red/black to battery, green/yellow to motor and thin blue/yellow to switch.

First off, removed the cut bit of the red (receiver) wire, It comes out of that little hole, and can be de-soldered from the back of the board

Next, removed the yellow and blue wires in the same way (already removed in pic below) and replaced with red wire (to receiver plug)

I left a fair bit of exposed core on the red wire, as I needed to bridge the yellow and blue wire's respective holes together.

It seemed easier than trying to solder a small, seperate, length of wire across the tracks

Here you can see the new red wire coming across the board from the left, meeting up with the black and white wires that go to the receiver plug

Here's the hole the switch wires came through originally

And here's the new, 7.2v feed receiver wiring

It's working fine at the minute

[richytanimal]

Ooh, might have to give that a go[]

[hellbelly]

Nice work....

Did you burn yourself []

[TWINSET]

I've never burnt myself with a soldering iron, only Deans connectors, newly tinned wire, motor terminals, capacitors, hot air guns, freshly shrunk batteries, but never a soldering iron

[hellbelly]

actually, thinking about it - that was good fo them to help you tinker!

[TWINSET]

Definitely - most companies wouldn't even suggest that changing the battery plugs was ok

The guy I spoke to was extremely helpful, even phoned me back during my hacking to warn me that the receiver may pop with 7 volts going through it (1471 does have it's uses)

Like I said, this isn't a Speedmaster recommended modification, and probably voids the warranty