No motion with HM7000, just sound and lights

[L NERd]

I have 7 locos fitted with HM7000 two of which steadfastly refuse to move. Sounds and lights function normally but they are very reluctant to ‘go love’s d usually take 3-4 ‘refresh host’ scans before recognition.

I can’t see any threads with these issues so it looks like I’m the only one doing something wrong —- and then repeating it!

Any ideas?

[96RAF]

Try a simple power cycle of each errant loco, by rocking the loco wheels off track at one side.

If that doesn’t work, un-assign the decoder from its loco, delink and delete it from the app, then rescan, relink and reassign.

Edit - I had this happen twice today on separate locos. The un-assign, delink and delete, then relink and reassign worked for both but it is a pest to have to do it. There must be an easier way to restore such a loco.

[P-Henny]

I can't point you to them, but this issue has definitely been reported before in posts many times, so you are not alone.

The search function on this forum is dire, probably why you can't find the previous posts with your issue.

As I have no interest in HM7000, I can't recall what previous advice and/or resolutions have been documented in posts.

I daresay someone will be along shortly to re-invent the wheel and give the same guidance as before once again.

[WilliamDavid]

I had this happen with a Schools Class locomotive yesterday.

Tried all the tricks to no avail.

Found the loco/tender connector was loose.

Didn’t think the decoder worked without a motor connection.

[Alan-3648611707821020]

I tried the unassign, delink and delete but I have the same symptoms of all working in both modes except no motor drive, any other ideas??

[96RAF]

You need to unplug the decoder, fit a blanking plate and prove the loco is good on DC. If not then it’s not the decoder. If it is OK then try a reset of the decoder by writing value 8 to CV8. This will put the DCC address back to 3 so you will have to write its old address again even though it still shows in the app.

[ColinB]

It sound like as someone mentioned earlier a bad tender connection. Now the next question is "is it the new type tender connection or the old one"? The old one is the four wires that terminate in a small white connector on the tender. If it is the old one it could be the connector is not pressed home fully in the socket, I have even had it happen on new ones. So the loco will work with sound because of the tender pickups, but the connection to the motor is not made. If it is the new type I haven't got a clue. As 96RAF said try it with a DC header to check that the loco is working properly.

[SteveM6]

I may have missed something but which locos are causing the issue? You mention sound and lights but the mention of lights precludes a tender being involved.

As RAF96 suggests, a full power cycle of loco, phone/tablet and testing on DC should be your first steps.

[TezzaG]

I had this a few months back, and again today, the solution is to slide the speed up to over 75%, a Hornby tech told me this, its a known error. My one today was a new Coronation Class with new decoder, sound profile was installed and working with no errors, but no wheel movement, until I moved the sider over 75%, then it kicked into life.

[Brew Man]

Are you saying it then behaved normally thereafter?

[TezzaG]

On the Coronation I've done today, it runs something like normal, then every so often, intermittently, it wont react until I push it above 75% again. Its a definite error/bug in the app or the decoders.

[Fishmanoz]

Certainly seems to be a weird one. Daedalus has reported being able to run locos with only 5V going to track so something less than that going to motor drive (well < 75%).

Moderator issue to check out given Hornby Tech reported to be involved?

[96RAF]

An update is under test that fixes the issue of sound and lights but no motor control, which can occur after a transient power loss on track. Once checked out all profiles will be updated to the live app with this fettle as one of several improvements. Hopefully that will be the end of the irritation.

I have no idea how Daedalus is running from 5v as Hornby response to making the power bank smaller was that 2 super caps at 2.7v each (5.4v total) wasn’t enough to keep a decoder booted up, whereas 3 caps did (7.2v total).

[ColinB]

Actually the capacitors charge up to what ever the charging voltage is, which if that circuit diagram is right is the value of the Zenor - 0.7 (forward base emitter voltage drop). I think if I remember from the circuit the capacitors were in series which means that every time you add another one it lowers the overall capacitance. They use them in series because the voltage rating on each capacitor is not high enough for just one. My analogue electronics is a bit rusty but correct me if I am wrong.

[SteveM6]

I don’t think the OP has mentioned capacitors. I can see why RAF96 has bought them into the equation (to challenge the statement that someone has run a loco on only 5v ie below the boot up voltage), but we don’t need to go off on a tangent and confuse the OP.

[ColinB]

Yes but unless I am completely wrong that statement is completely misleading, it even confused me, so I dread to think what it would do to others. If you post something technical make sure it is right. As to the 5 volts it could be that the DC on the track is not true DC and the multimeter is taking the average. We know it works with a LaisDCC decoder, so it appears the fault lies somewhere else.

[96RAF]

I was comparing the output of the caps to the applied voltage Dd is getting from his gizmo.

Like battery cells in series, caps sum up their individual voltages.

Back to the OP.

[ColinB]

I think we better leave this, it might be vaguely like battery cells. I assume by individual voltages you mean its rating, that is the absolute maximum working voltage, go over that and if if is a tantalum it goes bang, nothing to do with how much voltage it stores.

[ColinB]

Yes Daedalus you are right, I assume there is a voltage regulator in there somewhere so there will be a drop across that. The 3.3 volt is not going to be hard and fast that is just for reliable operation you will probably find it works at a voltage lower than that. I assume the micro they used probably has the capability to go to sleep although they don't use it, so it probably works at a very low voltage but just very slow. As I said I had issues with TTS doing weird things I tried all the electronic hardware fixes I know and never resolved it. In the end it came to an issue between the decoder and the motor. It was a new expensive loco so I didn't swap the motor out to see if it resolved it, I just moved it to another loco of the same type where it worked. I have worked on microprocessor software for years and some of these issues are sometimes down to registers not being setup correctly or the right order when you write your start up code. Generally works most of the time but in those 1 in a million times it does something weird. Perhaps the answer is to send it back to Hornby and ask for a replacement, we know it is not the loco as the LaisDCC decoder works ok.

[96RAF]

OK - I give up. I should have known better than be dragged into such a diatribe.

Now stop wittering on about caps and get back to the OP plot.

[Fishmanoz]

My “technical post” was simply there to compare a faulty setup requiring > 75% of app volts to make it work v Daedalus’s reported 5 volt operation, which he has now clarified (if you want to see what he actually said on another thread, just check his posting history to see it had nothing to do with caps or meter rms errors).

Rob, does the update you mention fix the 75% problem?

[ColinB]

If you read the last line of my response I recommended returning it for a replacement. Looking at all the responses Daedalus has done all the normal checks he said it works perfectly on DC so that only leaves one thing. Hornby tech would probably spend ages trying to find it and they would probably need his loco, been there got the tee shirt.

[SteveM6]

The OP never came back and the 75% issue was raised by TezzaG.

[96RAF]

It appears to Fishy. The restart throttle value we were looking at previously was 50%, but likely that depended upon each loco, no matter as now after a power glitch I get a restart no problem and no need for all that delinking and deleting caper. ABC seems to work fine too.

[Fishmanoz]

Well summarised Steve to pick out the two with actual problems among the diatribe and wittering.

With TezzaG’s hopefully solved with the imminent update and no reply from the OP, I think we can all turn our attention elsewhere for now.