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[Martin (Admin)]

What is this?

 ( One point for every component individually correctly identified! )

[T888]

Bobs board speed controller 

[mrlownotes]

Definitely a Bob's board.
Archaic speed controller.
A resistance track for mounting on top of a servo.
Looks like the track wipers give approximately 7 levels of track resistance (forward and reverse) to maximum voltage.
I don't see much wear on the tracks.
I remember, as a boy, wishing to be able to afford radio control to be able to use a Bob's Board.

[chas]

Thats the remote version of a Bobs board, not the usual servo top model. Its missing two screws which makes it unsafe. I think that's the five amp version, proper matching to the motor was important for them to work well.

[dougal99]

Who's bob? And why have you got his board?
Is the touch pad relevant? A late mod maybe?

[Dean's Marine]

Hi nothing wrong with them, I have a good few models that still have them in and still working fine, and if you wire them up wrong the magic smoke warns you, swap wires around and it still works,  try that with electronics
 Ron

[Colin Bishop]

If you get the right match between the motor and the board they work really well as Ron says.

I had two of then in my Isle of Wight Ferry Shanklin which were wired up with limit switches to give mixing on a 2 channel  RX without the use of electronics. I still have the wiring diagram I worked out but I don't understand it anymore!

Colin

[Subculture]

Give me an ESC any day.

[Neil]

they were good little speed controllers in their day. i started off my rc career with these in the later 1970's.

only problem with them was if they came into contact with salt water that i used to sail on at fleetwood......they were soon kaput if they did
             

[Colin Bishop]

Having recently battled with an obscure fault in an all singing, all dancing electronic ESC there is something to be said for simplicity. In their time Bob's Boards were a clever solution at a very reasonable cost.

Sure, today's ESCs are electronic wonders, but many of them seem to need setting up and are not always happy with the signals from certain mainstream TXs. I have had to limit the throttle throw as otherwise the ESC simply cuts out. Other defaults can give you only 50% power in reverse. You can usually get there in the end but they are often not plug and play as were earlier units. Especially when they try to identify the battery being used and apply cut off parameters if they suspect the supply voltage isn't sufficient to protect the battery. A lot of the internal programming and default setup is focused on model plane or vehicle use which is not always what we want. Boats need reverse and they don't need brakes. A recent ESC I have bought seems to be a be a nice unit but simple forward and reverse at 100% each way is not one of the foremost options.

The phrase 'too clever by half' comes to mind.

It is understandable when people who are not experienced modellers come on here scratching their heads.

Colin

[Neil]

subculture

these were around before ESC's were a twinkle in yer daddy's eye.

[tassie48]

1970 Bob board i do remember it well fwd and reverse I thought I was it, my little tug boat bread and butter balsa wood model  pushing and pulling the barge around I think it is still in there good old McGregor radio gear servo directly screwed on to the state of the art controller back in the day everyone laughing when you came in then suddenly you could back out the  joy of having reverse tassie48

[Martin (Admin)]

Whern't  there different ampage boards for small, medium, large motors?

[Martin (Admin)]

We all called them 'Bob's Boards' but the proper name is....

[davem99]

It's a Bobs Board speed controller.
The base has tracks of resistance at the top for the red positive lead and the bottom for the blue negative lead.
The servo connector in the middle has two wipers that connect the motor output leads to the resistance tracks.
The metal half circles under the wiper was I suspect used to connect the motor output instead of how this version has been wired.
Battery connection is via the scree nylon block and The three pin plug could be for a fuse/emergency disconnect or rx power.
The centre wiper was controlled via a separate servo controlled by the rx.
In the centre position the wiper was off both tracks so no power to the motors.
There were a range of versions with different resistances to suit the motor being controlled and the current drawn on load.
Back in the day they were the best available for speed control.
ESCs were not generally available but I can remember using a 3055 transistor to make my first controller. Eventually made a full blown (tomahawk?) controller that used NPN & PNP transistors to give forward and reverse using a signetics chip.
Happy days and nice to see an example of this controller.

[Martin (Admin)]

 
Old advert: 
 

 
https://www.modelboatmayhem.co.uk/forum/index.php/topic,67680.msg731710.html#msg731710

[roycv]

Hi Davem99, Do you remember the 'Pompey' esc?  a round i/c chip and the o/p was to 4 big power transistors  Wired as an 'H' with the motor across the centre.  I made my one from a rolling tobacco tin with the lid as the heat sink.  Problem was that you lost voltage as each power transistor lost 0.7 volts across the emitter / base junction so 6 volts was reduced to 4.6 volts.
There was another little cct  you could add in which had the base current go through a small resistor and when there was 0.7 volts across the resistor this would turn on a small transistor which had a relay in the collector circuit and this relay had a connection from the battery by-passing the esc direct to the motor and so you got a full 6 volts across the motor and the heat sink cooled down.
Those were the days when building your own was a lot cheaper, not so now!
Roy

[warspite]

My first speed controller was a Bob's Board, fitted to my corvette in 1982, I even created a switch for forward and reverse using the same principle using vero board (copper tracks on a plastic substrate used in electronics projects)


Does Davem99 get most of the points as he named most of the parts, to which end I claim the points for the unmentioned terminal block, does the speaker cable count (black with white stripe being used for the motor connection).