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Or if you want a very good controller at a very good price you could build one of these

I used one of these before I went to the DARK Side with DIGITAL

QUOTE (JCS100 @ 9 Mar 2010, 09:51) <{POST_SNAPBACK}>Below is the updated diagrams for the controller used by 6 of the club members

Circuit Diagram

Construction Diagram

Build details and Spec for Club Controller

Controller is an updated Analogue design based on the Chris Frost design from some years ago. Main improvements is the addition of diodes on a rotary switch giving a stepped brake response, a partial drift brake and diodes added before full power stop negating the transistor step to full power.

Specification for the controller as follows

Peak power @10 Amps during acceleration (Transistor Dependant)
Full power rating +20A (based on Parma contacts)
Continuous rating at ½ power through Transistor @5 Amps depending on heat sink for transistor & transistor used
Working Voltage 8-25 volts
Braking adjustable in 0.3V steps (1N5148 diode drop)
Drift brake @2 diodes (1n4006) 1.4V
24 steps + full power on sweep
Start speed sets the initial motor speed from off to manic effectively changing the voltage range the controller will sweep over.
Traction Control, restricts the initial power into the motor making the controller less sensitive

Design suits Parma Turbo/ RED Fox controllers with separate full power & brake pads.

Construction. (Refer to supplied pics for details & orientation of components)

1. PCBA (SCD Wiper Board)
a. Note Wiper PCB is supplied either with or without mounting block, if without, then a suitable block with 7mm hole sized to fit between the Parma chassis lugs needs to be super glued to the non track side of the controller otherwise jump to (f).

b. Best method to position the wiper PCB correctly, is to locate block in controller lugs with Parma bolt, then dry fit the PCB on top to establish fit under wiper.

c. Wiper must sweep across the brake pad to full power pad at the correct height

d. Parma trigger movement stops may need to be adjusted

i. Brake button support can be bent backwards
ii. Full power stop behind trigger can be filed
iii. Wiper will need to be bent slightly to run at the correct pressure & angle across the wiper PCB

e. When satisfied with the position, mark a line on the rear of the PCB, roughen rear of PCB with sandpaper then super glue in position marked

f. Clean track pads at top of PCB with ink rubber

g. Form 1st resistor to hairpin form i.e. bend one leg 180 degrees back pass body, pitch the leads to suit pads.

h. Locate resistor on non track side starting on R/H side one leg goes to pad 1, 2nd leg goes to pad 2, making a connection.

i. Repeat for 21 resistors

j. With Reference to front view of wiper board solder diode from full power pad to adjacent pad diode orientated at shown.

k. From the non track side connect a hairpin formed diode from last diode pad to adjacent pad (note orientation).

l. Should now have a chain of resistors from pad 1 to pad 22, then diode chain from pad 23 to 25.

m. Locate PCB in lugs secure with Parma bolt

n. Solder brake diodes as shown in pic from brake pad PCB in a chain to the brake button on the controller.

o. Solder wire from full power pad to full power button

2. Cable connections Controller
a. Solder 1 core to full power Parma controller pad

b. Solder 2nd core to Parma brake pad

c. Solder 3rd core to last pad of resistor chain

d. Solder 4th core to the wiper

e. Lay cable to chassis of controller as shown and secure with tie wraps or hot melt glue

f. Locate chassis in to controller sides and mark where the cable is to pass out.

g. File/dremel cable access recess in both halves of controller.

3. Controller box bottom fixings
a. Drill suitable cable sized hole in L/H or R/H side of case bottom

b. Take 2 A 3 pin plug & remove top

c. Locate top centrally on bottom of case

d. Drill 2 fixing holes to hold to case avoiding electrical contact between case and plug pins when re-assembled

e. Drill 1 or 3 plug wire holes below position of plug in case

f. Locate multi-block connector inside case drill fixing holes & secure with screws

g. Locate transistor either in bottom or side of case, drill & secure with screw. (Note transistor requires insulating mounting kit such that the metal tab of the transistor does not electrically connect to the case)

4. Controller box top fixings
a. Print off dial sheet on normal paper, tape to front side of case top

b. Drill 3 holes sized to take the 2 resistor pots & switch pot threaded shoulder where marked.

c. Remove paper locate pots in correct position finger tight

5. Controller Case wiring

a. Wire up plug with suitable cable (Flexible mains lead cores 1.5mm etc)

b. Locate plug to case bottom feed wires through to multi-block, trim, strip ends and locate in block (see diagram)

c. Solder diode orientated as shown to Transistor legs

d. Connects wires as per diagram sheet 2 from block to transistor and to front cover pots.

6. Front Cover finishing
a. Print off dial sheet onto photo grade paper, allow fully drying then adding a spray coat of clear lacquer to protect print and give a wipe clean surface.

b. Carefully cut clearance holes for pot shoulders where marked

c. Undo nuts of pots, remove, apply contact glue to top cover then lay sheet in position

d. Replace nuts & tighten

e. Add Knobs!

7. Testing
a. With a multi-meter check that
i. Wiper at the brake position there is less than 1 ohm between neutral pin and earth pin
ii. Live pin to earth pin is showing as no connection (high ohms)
iii. Wiper at full power Live pin to neutral pin is showing as less than 1 ohm
iv. Earth pin to Neutral pin is showing as no connection (high ohms)

b. Place car on track

c. Set Controller brake to 100%

d. Set traction to 0%

e. Set Start speed to 20%

f. Plug controller in to 3 pin socket, Lift back end of car pull trigger slowly
i. Motor should increase in speed
ii. Should reach full power at end of travel
iii. When trigger released motor should stop instantly

g. Common faults
i. Motor does not run until full power button reached
1. Check Transistor & wiper board wiring at end of resistor chain
ii. Controller case gets hot
1. Disconnect immediately!
2. Check for soldering shorts between brake pads & resistor chain
3. Check transistor leg wiring
4. Check for shorts by following wiring diagram ensuring the correct wires are connected to the correct point.
iii. Start Speed/Traction control works in reverse
1. Wiring to pots outer connection is on wrong side, swap over.
iv. No Brakes
1. Check orientation of all diodes on wiper PCB & brake pot, 1 wrongly connected diode will stop the brakes from working.

Apologies for the carp formatting, original notes written in word did not copy over that well.
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