PWM speed controller

[vjoneslong5040]

Morning all! Sorry I haven't been around much, I used the Christmas break to get my head down and get another chapter written! Hoorah!

Anyway, just before Christmas I ordered a Andel PWM speed controller to fit to a Busted bricks loco. I was intending to run on 3AA batteries, and the Andel model was advertised as having a voltage input of 3.5V to 12V, so I thought it would be okay.

I followed the instructions, but I don't get any variation in motor speed. I was just wondering if any one had any suggestions for trouble shooting? I can wire up a circuit, but when it gets to more advanced electronics I can get a bit lost! I've already tried swapping round the wires on the potentiometer, but to no avail.

I've also tried contacting Andel, but I have had no response to my enquiries. I've attached some images of what I have done so far.

Many thanks!

[hussra]

(Brief de-lurk)

I too have one of these AnDel manual speed controllers, going into the same type of loco as yours. Mine works nicely... good piece of kit so far.

Looks like you have the pot wired up correctly: blue to centre pin, white and green to the two outer ones. But I'd start the diagnostics in this area.

Do you have a multimeter handy? If so, set it to measure resistance in a range up to 100K or so (mine has a 200K range which is ideal) and set the pot to the middle of its range. Then, with the battery disconnected, measure the resistances between the points on the speed controller board where the blue, white and green wires join. You ought to get about 100K between green and white and 50K between green and blue, and white and blue.

Yes, you need at least three hands for this. The 100K should stay the same as you adjust the pot but the other two figures will change (still adding up to 100K).

If vastly different from that, suspect the pot and its wiring. (In which case repeat the measurements at the three terminals on the pot; if still wrong there, replace the pot. If right there, suspect the wiring and check continuity of each wire in turn.)

Out of interest, how are you planning to fit all the bits in? I've managed (with considerable wangling) to get it all under the bonnet and leave the cab clear, but it's a blooming tight squeeze.

[vjoneslong5040]

Thanks very much!

My multimeter is broken so I think this a good excuse to replace it. I have tried swapping round the three wires for the potentiometer, but it hasn't made a difference. I'm mostly annoyed with Andel for never getting back to me. Ah well!

I found that if I fixed the battery pack on the top of the inside of the bonnet and as close to the front as possible it worked absolutely fine, there is just enough space. I just have to be careful with squeezing all the wires in.

[hussra]

Thanks very much!

My multimeter is broken so I think this a good excuse to replace it. I have tried swapping round the three wires for the potentiometer, but it hasn't made a difference. I'm mostly annoyed with Andel for never getting back to me. Ah well!

I found that if I fixed the battery pack on the top of the inside of the bonnet and as close to the front as possible it worked absolutely fine, there is just enough space. I just have to be careful with squeezing all the wires in.

Good luck with the troubleshooting... plenty of other things that could have gone wrong and that we can look at, but the area around the pot seems a likely place to start. I too have been waiting for a reply from AnDel (about something completely different and less urgent, in my case) for about 6 weeks).

[vjoneslong5040]

Well I finally got round to fiddling with the pot. It would seem fine, with it always adding to 100k between blue and green/white and always a 100k across green and white. What's the next thing to check?
Thanks for the help!

[hussra]

Hmmm, so that's looking OK.

Ummm, check whether you've had an email back from Andy Bell? There's also a couple of phone numbers on his web site (under "Enquiries") which might be worth a go, both daytime and evening?

I'm afraid my speed controlled has got built into the loco since last week which is going to make it harder work coming up with what to check next.

[vjoneslong5040]

No worries. I'll try giving him a ring but I'm not hopeful for a reply. I did wonder as there a couple of holes on the bottom so I wonder if it's missing a component. But then I guess it wouldn't work at all!

Thanks for all the help though!

[hussra]

I think the phone call has to be worth a go. I seem to remember some empty holes on mine too.

[vjoneslong5040]

Well I spoke to Andel and its all sorted now. It turned out to be a connection where the solder ran across, between the negative and yellow. It made the electricity bypass the circuit, hence the motor always running at full pelt. Works a treat now.

So for anyone who gets a Andel PWM speed controller and it doesn't work, check the negative and first yellow wire are not shorting (i.e. joined).

Yay!

[hussra]

Really glad to hear that - hurrah!