Port failure with NCE Switch-8

[RFS]

I was running the layout this afternoon when I got an unexpected short circuit. The layout was being operated at the time using RR&Co automation, with a Lenz set 100 DCC system.  The short was due to a train leaving a storage road but its turnout was not set correctly, and hence the train had shorted on the frog.  The turnout is operated by a Tortoise motor attached to an NCE Switch-8 with address 120, and the Switch-8 has 8 ports addressed 120-127.  I was unable to operate the turnout with the Lenz throttle either, so it's not an automation problem. Checked all the wiring was OK and tried powering off and on, but still no joy. However, turnouts on addresses 121-127 were all OK. As a last resort I put the Switch-8 into setup mode and re-addressed 120, after which all was OK again.

 

Well for another 5 minutes, that is, until another short occurred at the other end of the layout. Exactly the same symptoms, except that it was a different Switch-8 with addresses 150-157, and 150 was dead until re-addressed.

 

Now these switch-8s were installed best part of a couple of years ago, and I've not seen this problem before. The DCC track is protected by a PSX but the NCE Switch-8s are on an accessory bus that bypasses the PSX so they should not be affected by track shorts.

 

Any ideas?

 

 

Edited December 5, 2015 by RFS

[RFS]

Well it happened again today with one of the two that had this failure yesterday.  I raised the issue with NCE and got this response:

 

"You can send them in for repair if you like.  But the shipping may be cost prohibitive.  Maybe use it as Switch-7?   If not send them in. It will only affect the first channel, and will probably keep reoccurring."

 

So it looks to me like a known problem. Sending back to the US is going to be expensive and leave me without the railway for several weeks. I have 7 of these and currently 4 spare addresses, so I've rewired the 0 ports of 4 of the units onto the current spares, and on the other 3 I've changed things around so that port 0 is only a trailing turnout exiting the storage yard.  So if the failure recurs on these, I'll just get a short, rather than a train careering off down the wrong track.

[Crosland]

If you bought them in the UK then the UK supplier is liable if you can show they are faulty (that comment from NCE looks pretty damning to me, too).

 

Andrew

[RFS]

6 out of 7 were bought from Bromsgrove Models in 2011, so they're out of warranty and Bromsgrove Models are no longer in business.  I think I'm just going to have to work round the problem.  Simplest will be to buy another and for it do manage all the port 0 turnouts.  Just strange I've had these for over 3 years now and two have decided to show this problem at the same time.  I'll see how it goes.

[Crosland]

Warranty is irrelevant if there really is a known manufacturing fault. Bromsgrove not existing is a problem

 

Andrew

[RFS]

Well I feel reassured that no-one's reported a similar issue, despite there being many users of similar kit out there.  So it means the problem can't be widespread and gives me confidence that it's not going to be an ongoing problem! Meanwhile all of my port 0s are either spares or are operating turnouts that are only ever trailing ones, hence if a problem arises there'll be an immediate halt via a short on the frog, rather than a fast-moving train careering off down the wrong road, with possibly damaging consequences! An extra 2-port Switch-IT might be a lot cheaper bypass if any more problems arise ...

[malcolmy]

I have had a similar problem a couple of times, over maybe a twelve month period.

 

It seems that channel 0 'loses' its programmed address sometimes.

 

I just re-program it (once I've found a jumper!) and all is well again.

 

I have 5 Switch-8s installed, and it's only ever happened on one of them. Control is from an NCE PowerCab with S5a booster.

[Gustaclau]

Hi. Like I saw you have some experience with NCE Switch8 I would like to take the opportunity to talk about the problem I got while I was connecting for the very first time a NCE Sw8 to ma ROCO Z21. The address display showed me twice the number 1 and then 3 fixed horizontal bars until I shut down the power. Based on the NCE booklet page 6, that means "Decoder has power but is not receiving DCC information". The NCE Sw8 was to connected directly to the Z21 through the two connectors of the Sw8. Any answer from you all will be welcome. Bests regards.

[RFS]

I can't comment on connecting the Swiitch-8 directly to the Z21, but it supposed to be connected directly to the DCC track bus. I'm also assuming you have the MK2 version - I only have MK1s which are quite different.

[RFS]

An update to this issue as a third one of my units suffered a failure recently.  This time it was the last port (channel 7) that suffered the failure.  Unlike the previous two failures, this port could not be recovered by re-addressing so the port was lost.  Luckily there is one spare port on this unit, but it's port 0 which might be suspect.
 
NCE's response was  - "Please send the board in for repair. That is a common issue with the first release. Typically, it involves a processor replacement. All NCE repairs are done at the factory."

 

As I was about to go to Australia for 3 weeks I decided to send in all 3 boards for repair. On receipt I got a message from NCE saying that, instead of repairing them, they could replace them instead with new MK2s at a cost of $93.  After checking that no more costs would be involved (import duty, RM charges etc.) I decided to take up the offer.  Works out at about £20 per unit to upgrade. New units cost £45.

 

I'll see how the new units perform.  One attraction of the MK2 is that you can supply separate DC power so that it doesn't take power from the DCC bus, just commands. 

[Phil S]

A possible 'problem avoidance' 'solution':   If the accessory decoders are on an accessory dcc bus fed from the (Z21/central unit - on the basis that THEY do not generally expect any short circuits, and the TRACK dcc bus distributions are fed via PSX's or equivalent due to the likelihood of shorts occuring with derailments and overrun points  ( possibly the equivalent since reports of PSXs recently bought appear to have differing time-response behaviour -suitability needs to be rechecked ) - so that the main unit remains active despite the trqck-short, then MAYBE the faut will not occur. ... it depends how it responds to the 'glitch' when the short starts....???

[RFS]

All my NCE Switch-8 units have always been on a dedicated accessory bus.  At the present moment that's a dedicated Lenz LV102, with the main track bus fed from an LZV100 through a PSX circuit breaker. So the accessory bus is protected from shorts, and I do not believe the fault is any way caused by short circuits.

[RFS]

Just a quick update on this issue as I have now received and installed the 3 replacement Mk2 versions of the Switch-8.  A very much improved product and much easier to address.  They're all installed and working, and no problems so far!

 

At the same time I picked up a 4th Mk2 unit from Ebay for the bargain price of £20 posted.  I have one Switch-8 controlling the main station throat, and with a number of cross-overs it's actually controlling 15 Tortoises.  It's never had a failure but I thought I'd replace it with the Ebay Mk2, as any failures to switch could be damaging if trains took a "wrong turning".  And a really good bargain it turned out to be, as the displaced Mk1 switch sold on Ebay for £27.  Needless to say, I'm on the lookout for further bargains like this!

 

One of the attractions of the Mk2 is that you can use an external DC power supply - 8-15 volts. I have a couple of spare Netgear power supplies providing 1 amp, 12 volts which work very well when I tested on one. I have 70 Tortoises which, at 16ma stalled power consumption, are taking a combined 1.2 amps out of my 5 amp Lenz system. Powering 4 of the Mk2s gets me over half that power back for the trains. Thinking about replacing the other 3 Mk1s with Mk2s to get it all back.

[jpendle]

Hi. Like I saw you have some experience with NCE Switch8 I would like to take the opportunity to talk about the problem I got while I was connecting for the very first time a NCE Sw8 to ma ROCO Z21. The address display showed me twice the number 1 and then 3 fixed horizontal bars until I shut down the power. Based on the NCE booklet page 6, that means "Decoder has power but is not receiving DCC information". The NCE Sw8 was to connected directly to the Z21 through the two connectors of the Sw8. Any answer from you all will be welcome. Bests regards.

 

Hi,

 

I just got a Z21 and a Switch 8 MK2. It won't work unless you turn Railcom off on the Z21. I know this is 6 months late for you sorry.

 

Also I posted a Switch 8 question on here earlier, I got a short across my main bus and my Switch8 now fails to power up properly, it gets as far as 3 bars and hangs up.

 

Any clues?

 

Thanks,

 

John P

[RFS]

I have a Lenz DCC system and I also have to turn off Railcom for the Switch8s (or rather the Lenz has an "NCE Compatibility Mode" which has to be enabled).

[melmerby]

I am coming to this topic a bit late because I have had some similar problems recently

 

I have 6 NCE Switch-8s driven by Lenz 100 system on a separate DCC bus to the track which is fed by a Digikeijs DR5000. Point motors are all Tortoise.

(Track bus does not affect point control which is completely independent)

 

I have had a couple of Switch-8s that sometimes appear to be "sleeping" e.g. they wouldn't operate the points but if the DCC system was powered down and up they would start working again. The rest of the Switch-8s work perfectly and have never faulted.

Note this is at switch on not after any fault condition. Once on properly they never give any trouble during an operating session.

 

One of the units eventually went into a permanent sleep and I couldn't wake it (the points were all left powered to their last set positions)

However after I programmed it again it now works perfectly. (for the time being)

 

Any suggestions as to the cause?

 

Cheers

 

Keith

[RFS]

I would suggest contacting NCE.  Losing address is a problem that occurs occasionally with the MK1 version. Had it a couple of times with mine, but I've not had any problems at all in the over two years since I last posted on this thread.  I have 7 units now - 3 Mk1s and 4 Mk2s.  Perhaps they might swap them for discounted Mk2s as they did for me and I've never had a problem with a Mk2. 

Edited February 28, 2018 by RFS

[melmerby]

I would suggest contacting NCE.  Losing address is a problem that occurs occasionally with the MK1 version. Had it a couple of times with mine, but I've not had any problems at all in the over two years since I last posted on this thread.  I have 7 units now - 3 Mk1s and 4 Mk2s.  Perhaps they might swap them for discounted Mk2s as they did for me and I've never had a problem with a Mk2. 

They are all pretty old now, well outside any guarantee.

The thing that was puzzling was the fact that it seemed to lose address "Slowly"

i.e. not working then starting to work again after a power off/on.

I've actually ordered a Mk2 (I already have some Switch-it Mk2s) plus a Mk1 which I found online, brand new in bag for £20

 

The only other failure I have had is when I lost two ports completely on one unit and it turned out to be a solder splash trapped underneath one of the SMD LM324 devices. It had destroyed the LM324, which I replaced and one output of the PIC

It means I now have one Switch-7 !

 

Keith