Please be careful you are working with voltage that will kill you !

Looking at the pictures I'd be confident enough to try powering it up.

Very important to take care with the mains voltages and DC outputs, but with the board on an insulated surface (wooden table top) and a meticulous policy "don't touch anything while the power is ON" it should be safe enough for a test run. Also, the capacitors ( Two large Black Cylinders marked 400V) can store enough power to give you a nasty shock even after the board is disconnected from the mains. After the board has been powered up leave it alone for at least 20 minutes to discharge.

The two red wires connect to a socket marked 'AC IN' so it's pretty certain they are the mains input. Like as not the electronics don't care one jot which way round Live and Neutral are but, as the wire on the right connects to a fuse, I'd connect that one to Live.

The motor connects to the terminal block marked J3 and the sides are marked M+ and M-

The control input is the red, green and black wire on socket J2. The circuit it connects to appears to be independent on the main board: it has it's own power supply off the yellow transformer and I believe the component marked PT1 is an opto-isolator. The board has been slotted around PT1 to separate the control section from the power section. Almost certainly the elaboration is to stop sweaty fat boys being electrocuted at the Gym!

Have to guess what the nature of the control signal applied to J2 is. It could be digital (like a TV remote) in which case the original controls or a compatible substitute will be essential. However, as the board at J2 is marked GND ( Black wire ), TRX (Green), and 5V ( Red wire) I think there's a good chance an ordinary potentiometer will work. I'd try a Linear pot like f:0″>this one from ebay

4.5k or 10k ohms should be fine. Green wire to the centre terminal. Red and Black to each side terminal. (If SLOW to FAST speed control goes the wrong way when the knob is turned, just swap Red and Black over.

• you mustn't touch the board when it's switched on
• freshly charged capacitors contain enough energy to blow the end off a screwdriver even after the board is disconnected.
• board placed on an clear insulated surface, no trailing wires, cups of tea, or metal tools allowed.
• Cross fingers, sacrifice a virgin, and it might work…

Dave

Can I just reiterate XD351 advice – please be very careful. 250v DC is much more potent as a killer / source of burns than the same voltage AC.

Don't just rely on switching off at the mains before touching anything as those two brown capacitors store sufficient energy to hurt you.

Electronics engineers would 'dump' the power from the capacitors using a resistive load to drain the power from them and keep this load applied before touching anything as capacitors tend to store a bit of energy even after they appear to have been discharged.

If in doubt you can hook bit of wire across the capacitor terminals – but don't be surprised if there is a flash and a bang as you do it which will make you jump!!

If in doubt you can hook bit of wire across the capacitor terminals – but don't be surprised if there is a flash and a bang as you do it which will make you jump!!

Me: You should do this with a resistor….its good practice..

If you don't hear from me you'll know it gone tits up 😂🤣I'm having a beer just now will have a look later on 😉.



Sean

Me: Well I hope you dont look later unless you are sober….

Edited By John Rudd on 30/12/2018 17:15:39

Practical experience says that a shock from 125VDC hurt a darn sight more than one from 230VAC. Just as well I didn't get myself across the whole 250VDC of the battery.

Andrew