Kato Controller speed dial not working - any advice?

[drt7uk]

Hi folks,

 

My Kato 22-014 controller has stopped accelerating or decelerating - it only goes on or off. Does anyone have any advice for me?

 

In more detail - when you switch from Brake to Forward or Reverse any train on the track will go very fast around the layout. The speed dial is not working...well I can turn it down from very very fast to very fast but that's about it.

 

I've tried turning off and on again, leaving overnight, pressing reset button, but nothing is changing. I've unscrewed and opened it up, but there is no visible fault or damage - all the wires appear to properly soldered.

 

Grateful for any advice!! I've bought a replacement but if I can repair this I could use it on my branch line or sell on eBay .

 

Many thanks, David

 

[Yavianice]

If you can't fix it, I use a spare controller just for switches and platform lights. 

[cteno4]

Sounds like the potentiometer shorted out and is now basically on full (no resistance).

 

jeff

[drt7uk]

4 hours ago, cteno4 said:

Sounds like the potentiometer shorted out and is now basically on full (no resistance).

 

jeff

 

Thanks Jeff. Is this something that can be replaced? In quite happy to get my soldering iron out, just not clear what's what on the circuit board.

[Kamome]

Have you tried removing the speed controller handle, then turning the potentiometer down. Does it stop turning and the power reduce to zero or just keep putting power through to the track?

[drt7uk]

1 hour ago, Kamome said:

Have you tried removing the speed controller handle, then turning the potentiometer down. Does it stop turning and the power reduce to zero or just keep putting power through to the track?

 

 

Thanks for the suggestion! But alas yes I've tried that and it's down all the way.

[cteno4]

You might be able to source a new pot for it, would be just desoldering 2 wires and soldering them onto the new pot. Could open up the throttle and see if the value (should be in ohms Ω for resistance and watts W for power rating). Probably a $2-4 part. If it’s isn’t printed on the pot it’s not going to be easy to determine the values needed. 
 

if you have a multimeter (or can borrow one) you could unsolder one of the wires to the pot and see if the resistance changes when your turn the knob. I’m guessing it’s shorted out and thus will show little or no resistance no matter where rotated to.

 

cheers

 

jeff

[drt7uk]

Thank you! Will see if I can work out the resistance and buy a new pot on eBay...looks like I can get them for only a few pounds like you say

[cteno4]

Yeah it’s just getting the max resistance and the wattage right. Many times it’s printed on the back or side of the pot. If there’s just some part number there try googling it with the word “potentiometer” or “variable resistor” to see if you can find it somewhere and get the values from there. You can replace it with a higher wattage (just costs more and adds safety margins) if you have to but I would not use a lower wattage pot. If you have bad fixed duty fees you might also check out your local electronics shop (if you have one that is, they are getting rarer).

 

cheers,

 

jeff

[drt7uk]

Thanks again Jeff...taken it apart and it says it's Alpha brand and 'B2K' which I'm assuming means 2K resistance. Have just bought this for £1.75! 

https://www.ebay.co.uk/itm/153373072828?hash=item23b5bf5dbc:g:aV4AAOSwb7RcYEud

 

Will let you know how I get on

[cteno4]

Most likely, but of concern is the power rating of the pot. generally larger pots like this tend to be the same power ratings based on the physical size of the pot, but I have seen larger pots the same size with different power ratings. Did you check that the shaft size is the same as well? That can vary to fit different knob types.

 

I would suggest not leaving this replaced one plugged in when not in use until you are sure it’s running well and not getting hot. I would first test the throttle with a multimeter if you can before a train! Solder to the same pins on the new one and you should be fine. Basically it’s center pin is the common and the outsides are either going 0>max or max>0 turning the pot clockwise, so worst case is throttle direction is opposite and just move outside wire to the other outside pin. Btw polarity here does not matter either wire can go to either pin, but best wire it up like it was.

 

worst case is there is a pop, wifi of the magic smoke comes out and circuit breaker fires! Hey it’s already he’s dead, Jim so nothing to loose.

 

jeff