Rapido/MR 16xx pickup problem

[CraigB]

So my just over 1 year old Rapido 16xx, bought through Model Rail, has basically stopped operating. It ran flawlessly for a year being the best of my fleet of locos for solid and slow running.

 

Track I’d fine and other locos are running without issue. The 16xx exhibits a lack of power unless nudged (the firebox led powers on) but within half a rotation it will

stop and the LED powers off.

 

looking at the wheels shows no major dirt build up and I’ve cleaned all the wheels and the pickups. One pickup at the middle wheel set doesn’t make contact with the wheel.

 

 

I took the DCC decoder out and put the DC blanking plug back in and tested it with a DC controller and bare contacts. Looks like the middle contacts when applied directly from the DC controller supply power fine but the outer sets do not supply power even when DC is applied directly to them.

 

My suspicion is that there must be conducting springs pushing the contacts onto the inside of the wheels and that these have either compressed or broken.

 

Yet to hear back from Model Rail or Rapido but since I live in NZ, sending it back for repair isn’t going to be an option. (I’ve done repairs before but this Rapido 16xx looks a lot more complicated than the Bachmann Jinty wheel set replacement I’ve tackled before).

 

Any thoughts or recommendations before I tear it down?

 

I might post a photo or two of the contacts when I can..

Edited April 22, 2022 by CraigB
Grammar

[Re6/6]

Hello Craig and welcome to the forum,

 

These pictures might help. If you wanted to check the individual sprung pick-ups, from memory,  it's fairly straightforward to remove the plastic keeper plate.

 

Ignore the screw shown in one of the pictures, I converted it to P4 and this was for extending the plunger for the wider gauge.

 

    

 

 

 

 

 

Edited April 22, 2022 by Re6/6

[Roddy Angus]

Hi Craig

 

I would suggest getting in touch with Rapido using the warranty form on their their UK website.  There is a known issue with the pickups and I recently had them replaced free of charge.   It was a smooth process and they sent me a return postage label, so there was no cost to me.

 

Best wishes Roddy 

[CraigB]

Thanks folks for info, looks like I’ll follow up with Rapido and see if I can get the replacements. 
 

Thanks for the photos Re6/6, how did the P4 conversion work out? I saw a number of posts on the possibility of a P4 conversion but there was some doubt that the chassis design allowed for the wider spacing?

[Re6/6]

Hello Craig,

 

The Rapido design was quite different to what one might have expected. The body was combined with some of the chassis so pulling apart in order to fit a new brass chassis wasn't an option!

 

In the end (contrary to some reported views!) doing the conversion turned out to be very straightforward, except that I did all the right things but just in the wrong order!

 

If you are going to convert one I'll put up some more pictures.

 

[Butler Henderson]

Has the loco had a short on the layout, the current drawn which the decider would have shut down against may have caused a spring to fail, one of the prime weaknesses of the Airfix 14xx.

[CraigB]

7 hours ago, Butler Henderson said:

Has the loco had a short on the layout, the current drawn which the decider would have shut down against may have caused a spring to fail, one of the prime weaknesses of the Airfix 14xx.

That’s quite a likely scenario, I had mistakenly run into a mis aligned point..

[CraigB]

8 hours ago, Re6/6 said:

Hello Craig,

 

The Rapido design was quite different to what one might have expected. The body was combined with some of the chassis so pulling apart in order to fit a new brass chassis wasn't an option!

 

In the end (contrary to some reported views!) doing the conversion turned out to be very straightforward, except that I did all the right things but just in the wrong order!

 

If you are going to convert one I'll put up some more pictures.

 

Good to know. I’m fairly new to the hobby so still grappling with a lot of new skills so no plans to tackle P4 yet (the less than prototypical track is bothering me so it could be sooner rather than later..)

[Re6/6]

If you do Craig, let me know and I'll sort out some pictures for you.

 

All the best

 

John

[boxbrownie]

8 hours ago, Butler Henderson said:

Has the loco had a short on the layout, the current drawn which the decider would have shut down against may have caused a spring to fail, one of the prime weaknesses of the Airfix 14xx.

I wondered that, Imhave had that happen with a 7mm Loco with plunger pickups, the springs were just not man enough to take the full current and they basically get hot enough to lose their “spring”.

[DCB]

11 hours ago, Butler Henderson said:

Has the loco had a short on the layout, the current drawn which the decider would have shut down against may have caused a spring to fail, one of the prime weaknesses of the Airfix 14xx.

The springs don't just have to cope with the decoder current, as when running into an incorrectly set live frog point there is a straight short across the  controller and that will heat and damage the spring in the plunger no matter how quickly the overload trips.  With DCC being up to 4 amps applied all the time, about 4 times the maximum 12 volt DC usually delivers.  That Short circuit is a same side short between wheels on the same side of the loco being at opposite polarities across an insulated fishplate.    This issue dogged the Airfix 14XX and my last one had to be fitted with springy copper strip pickups as I finally ran out of serviceable pickups, I got through about 20 of them and that's on DC.  Running into incorrectly set live frog points which didn't bother my other locos was the undoubted cause.

I would suggest you source some new pick ups or pick up springs for the 16XX, get a pack of 20 while you are at it.

Edited April 22, 2022 by DCB

[CraigB]

Well I bit the bullet and pulled the springs out to inspect. One was compressed but the others were fine.

So I’ve taken off the shell and done continuity tests from the wheels to the circuit board and all the way to pins on the plug for the decoder. Continuity is all fine and sitting the loco on powered tracks and measuring the voltage confirms the pickups are actually fine.

 

I sat the loco on the tracks with the decoder in place and the firebox led lit and gently moved the loco laterally and along the track. Decoder stays on and led stays lit. Then I moved the throttle forward and it died. Left it on the track and within a minute the led will turn back on.

 

I guess this means a fault on the PCB somewhere, probably a capacitor? And probably only way to resolve is a replacement board from Rapido? Who have yet to acknowledge the warranty form..

[boxbrownie]

5 hours ago, CraigB said:

Well I bit the bullet and pulled the springs out to inspect. One was compressed but the others were fine.

So I’ve taken off the shell and done continuity tests from the wheels to the circuit board and all the way to pins on the plug for the decoder. Continuity is all fine and sitting the loco on powered tracks and measuring the voltage confirms the pickups are actually fine.

 

I sat the loco on the tracks with the decoder in place and the firebox led lit and gently moved the loco laterally and along the track. Decoder stays on and led stays lit. Then I moved the throttle forward and it died. Left it on the track and within a minute the led will turn back on.

 

I guess this means a fault on the PCB somewhere, probably a capacitor? And probably only way to resolve is a replacement board from Rapido? Who have yet to acknowledge the warranty form..

There was a published fix which entailed “clipping” off the capacitors, I believe the fix is highlighted in the Youchoos site for this Loco.

 

edit: sorry cannot find the link for the fix as it was bookmarked on RMWeb and we know what happened to all our old bookmarks there! 😉

Edited April 24, 2022 by boxbrownie

[CraigB]

Update: Rapido has got back to me and have confirmed that what I’m experiencing is indeed the springs and that effectively they’re not transferring the full current even though there’s continuity.

 

Improved replacement springs are going to wing their way to me across to the other side of the world shortly. Looking positive and I’ll share the result once the transplant is complete.

[CraigB]

I got the springs yesterday from Rapido. Thankfully  with additional spares since the process of swapping them out is a little fiddly and it turns out I don’t have the greatest fine motor control. One took off like it had been shot out of cannon and I bent another.

 

However the good news is that it solved the problem and it’s back running smoothly again. There’s a small pause on each rotation when it’s running backwards, which I think is something binding. I’ll have to open it back up and investigate but otherwise I’m really happy with the outcome considering it was basically inoperable before.