A second problematic Massoth decoder

[Airbuspilot]

In my previous post I had a problem with a totally unresponsive decoder, now we have a problematic decoder in a newly acquired Locomotive described as - LGB 20900 Loco shunter with 65002 sound module. I cannot find documentation for this number but can find 21900 and 22900, I assume the one we have is quite old. The Loco is numbered 3005.

This loco makes noise, lights ON, jerky movement when writing CV's but doesn't drive when on the main track. As far as I can see everything is working as expected except I cannot drive it.

Loco on programming track.

LOCO no 3005

CV 1 - 4
CV 7 - 13
CV 8 - 123 Massoth
CV 17 - 203
CV 18 - 189
CV 29 - 34

I have been recommended to check no consist address entered and to switch OFF mfx. I have seen two possible CV's to disable mfx CV 12 + 50, i'm not sure which is correct so I have disabled both.


CV 19 + 20 both show 0

CV 12 + 50 both show 0.

When placed on the programming track and power applied the lights come ON and an engine noise starts. When I select CV programming mode (ZIMO MX 32 FU / E + MN) the noise stops and lights stay ON. Hand set reads address correctly, lights flash and loco judders when command sent.

When placed on main track and power ON lights are OFF, engine noise heard but Loco doesn't drive. None of the function keys work. I have tried operating with the ZIMO MX 32 and with the Roco Z 21 on my iPad with same zero result.

ZIMO support cannot see a reason for what seems to be a functioning decoder not being driven by the hand set, they think either the decoder is only mfx (seems unlikely as it responds to DCC CV commands) or I need to find another solution to disable mfx.


While I can identify the decoder manufacturer how do I identify the actual decoder?

Any thoughts appreciated.

Robin

 

[SevenOfDiamonds]

how do I identify the actual decoder

I'm not sure if that loco . . .


. . . was ever sold separately but it was definitely included in MTS starter set 70255/78255 . . .

Lgb 70255 Manuals

Lgb 70255 Pdf User Manuals. View online or download Lgb 70255 Instruction Manual

www.manualslib.com

or http://www.gbdb.info/data/manual/LGB/70255.pdf

. . . so has (or at least had) a standard LGB decoder fitted at the factory.

The 65002 sound unit . . .

. . . was obviously added by a previous owner.

Over to others help you diagose the problem (the switch in the cab is set to the highest number, I presume).

Cheers

David

 

[Airbuspilot]

I'm not sure if that loco . . .

View attachment 325661
. . . was ever sold separately but it was definitely included in MTS starter set 78255 . . .

View attachment 325662

. . . so has (or at least had) a standard LGB decoder fitted at the factory.

The 65002 sound unit . . .
View attachment 325663
. . . was obviously added by a previous owner.

Over to others help you diagose the problem (the switch in the cab is set to the highest number, I presume).

Cheers

David

Thanks for the info David, Yes the switch is set correctly. Certainly possible someone changed the decoder if they added a sound unit.
Robin

 

[dunnyrail]

Really you should be looking and programming the decoder and sound unit separately and disconnected. Whilst they work together programming of the units must be done separately. If you need sound decoder CV’s I can copy them here for you.

 

[Airbuspilot]

Really you should be looking and programming the decoder and sound unit separately and disconnected. Whilst they work together programming of the units must be done separately. If you need sound decoder CV’s I can copy them here for you.

I didn’t realise there were two units until i saw Davids post. I knew only one decoder at a time for programming but assumed a single decoder installed, seems i was wrong. I will try again on Friday morning all being well after opening the Loco up and disconnecting.
I will come back to you for the CV’s if I can make the Loco drive.
Thanks
Robin

 

[Diesel2000]

While I can identify the decoder manufacturer how do I identify the actual decoder?

Any thoughts appreciated.

Robin

You cant identify the actual decoder without opening it up. I can also guarantee that whatever decoder is in there is NOT MFX capable and those CVs do not apply. Massoth decoders are DCC-only, as were the original MTS decoders, which is likely whats in here (Massoth made them for LGB). The previous locomotive (20275) has an MSD3 decoder, which is produced by Marklin. An older loco like this is not going to have that, therefore all the CVs outside of the NMRA standards for DCC are different.

Based on the CVs you read out this loco's address is 3005

CV29=34 - 4 digit address
CV17=208
CV18=189

Those 3 CVs determine that this loco is using 28/128 speed steps, 4-digit address, and address of 3005.

I would recommend opening it up and determining what all is in there and then finding the proper documentation with the CVs that you want to adjust. You can then also test the motor, etc appropriately.

Edit, there is a good chance that by changing CV50=0 you may have burned out the lights. What was this setting before you adjusted it?

 

[PhilP]

So what address are you using to try to run the loco?
My 'guess' would be '4'?
CV29 set to '34' means you are using a long address..

Changing CV's, generally:
Read the value first..
Work out what it controls, and if the present value makes sense.

Case in point:
A Massoth decoder (certainly of the age in this model) CV50 controls the lighting outputs voltage divider.
In a Marklin MFX decoder, CV50 controls which protocols the decoder will respond-to / ignore.

<Edit>
Typed whilst Diesel2000 was posting.

PhilP

 

[Airbuspilot]

You cant identify the actual decoder without opening it up. I can also guarantee that whatever decoder is in there is NOT MFX capable and those CVs do not apply. Massoth decoders are DCC-only, as were the original MTS decoders, which is likely whats in here (Massoth made them for LGB). The previous locomotive (20275) has an MSD3 decoder, which is produced by Marklin. An older loco like this is not going to have that, therefore all the CVs outside of the NMRA standards for DCC are different.

Based on the CVs you read out this loco's address is 3005

CV29=34 - 4 digit address
CV17=208
CV18=189

Those 3 CVs determine that this loco is using 28/128 speed steps, 4-digit address, and address of 3005.

I would recommend opening it up and determining what all is in there and then finding the proper documentation with the CVs that you want to adjust. You can then also test the motor, etc appropriately.

Edit, there is a good chance that by changing CV50=0 you may have burned out the lights. What was this setting before you adjusted it?

Thanks Diesel2000 and PhilP

I haven't changed the values of any CV's which I didn't understand, I Changed 2,3,4 where I think I would not do any harm. CV's 12 and 50 were read as 0 not changed by me and the lights are OK.

I have

You cant identify the actual decoder without opening it up. I can also guarantee that whatever decoder is in there is NOT MFX capable and those CVs do not apply. Massoth decoders are DCC-only, as were the original MTS decoders, which is likely whats in here (Massoth made them for LGB). The previous locomotive (20275) has an MSD3 decoder, which is produced by Marklin. An older loco like this is not going to have that, therefore all the CVs outside of the NMRA standards for DCC are different.

Based on the CVs you read out this loco's address is 3005

CV29=34 - 4 digit address
CV17=208
CV18=189

Those 3 CVs determine that this loco is using 28/128 speed steps, 4-digit address, and address of 3005.

I would recommend opening it up and determining what all is in there and then finding the proper documentation with the CVs that you want to adjust. You can then also test the motor, etc appropriately.

Edit, there is a good chance that by changing CV50=0 you may have burned out the lights. What was this setting before you adjusted it?

Thanks Diesel2000 and PhilP

I didn’t change CV’s 12 and 15 they both read as 0.

The Loco is now open and I have attached a picture of the decoder. As David predicted there is a sound unit 65002 in the drivers cab which looks like an addition.

Presumably this is an original decoder and probably an old version. I will disconnect the sound unit and try on the programming track tomorrow. Is it identifiable?

Robin

 

[SevenOfDiamonds]

Presumably this is an original decoder

Yes. The label top left includes "20900". While the upper board might be generic, the lower board is specific to this model, presumably including the circuitry for the flashing lights on the roof.

Cheers

David

 

[Diesel2000]

What you have there is a factory installed LGB 55021 MTS decoder. There's a thread on this exact model already that you should have a look at:

LGB 20900.1 and CV programming

Have an old LGB 70255 starter set (digital starter set, 2x digital locos, MTS-1). The diesel loco is labelled 20900.1. I also have a Roco z21 XL central station & Decoder Pro. Using either Decoder Pro or the z21 computer app (not the iPhone cab app), I can read/write all CVs for the steam...

www.gscalecentral.net

 

[LGB333]

Thanks Diesel2000 and PhilP

I haven't changed the values of any CV's which I didn't understand, I Changed 2,3,4 where I think I would not do any harm. CV's 12 and 50 were read as 0 not changed by me and the lights are OK.

I have

Thanks Diesel2000 and PhilP

I didn’t change CV’s 12 and 15 they both read as 0.

The Loco is now open and I have attached a picture of the decoder. As David predicted there is a sound unit 65002 in the drivers cab which looks like an addition.

Presumably this is an original decoder and probably an old version. I will disconnect the sound unit and try on the programming track tomorrow. Is it identifiable?

Robin

That's a Massoth L DCC Driving/Function decoder (no sound) plugged into the DCC Interface into the locomotive's main circuit board. The LGB 65000-series Sound Modules are sound-only decoders. I've attached the L Decoder's User and Configuration Manuals for your review.

I've also added the LGB 65000 Series User Guide.

 

[PhilP]

There do seem to be recurring threads about this loco, and 'spurious' values being returned?

The Z21 also seems to be a common factor in these threads?

Specific to this thread:
Remove power to the 65002 sound module, and see what results you get.

PhilP

 

[LGB333]

That's a Massoth L DCC Driving/Function decoder (no sound) plugged into the DCC Interface into the locomotive's main circuit board. The LGB 65000-series Sound Modules are sound-only decoders. I've attached the L Decoder's User and Configuration Manuals for your review.

I've also added the LGB 65000 Series User Guide.

I stand corrected, the DCC decoder installed on the main board is an LGB 55021 MTS/DCC Driving/Function Decoder. Massoth produced the LGB MTS components for LGB and the updated replacement decoder is the Massoth L Decoder. I've attached the LGB 55021 Decoder's User Guide.

 

[Airbuspilot]

Gents

Thank you all for this information, I will need to study over the next couple of days. We meet again on Monday morning so I have time to see what, if anything, we will be able to do.

Thanks for the quick responses

Robin

 

[Airbuspilot]

I had some time so I came to the railway this afternoon.

Cab removed and sound unit and rear lights unplugged.

On programming track loco responds to CV reads and writes. loco judders and moves along the track, lights disconnected.

CV 17. 203
CV 18. 189
CV. 29. 34

Loco No. 3005

On main track loco doesn’t respond to throttle.

I thought about a decoder reset , is there a risk of decoder putting full voltage on lamps after reset?

Power is being drawn from track and motor seems to be OK. Am I looking at a new decoder?

Robin

 

[Gizzy]

I had some time so I came to the railway this afternoon.

Cab removed and sound unit and rear lights unplugged.

On programming track loco responds to CV reads and writes. loco judders and moves along the track, lights disconnected.

CV 17. 203
CV 18. 189
CV. 29. 34

Loco No. 3005

On main track loco doesn’t respond to throttle.

I thought about a decoder reset , is there a risk of decoder putting full voltage on lamps after reset?

Power is being drawn from track and motor seems to be OK. Am I looking at a new decoder?

Robin

Just a thought but is the quartering okay? It seems you can read and write and the loco judders as expected.

But when you try to move on main, I was thinking the rods had locked up.

I've had this on my own 20901 loco....

 

[PhilP]

I would write '2' to CV29 and try the short address in CV1.

Check all positions of cab-switch (if fitted).

PhilP

 

[Airbuspilot]

Just a thought but is the quartering okay? It seems you can read and write and the loco judders as expected.

But when you try to move on main, I was thinking the rods had locked up.

I've had this on my own 20901 loco....

Hi Gizzy
I can push it along easily so that doesn’t seem to be a problem.

 

[Airbuspilot]

I would write '2' to CV29 and try the short address in CV1.

Check all positions of cab-switch (if fitted).

PhilP

Again thanks Phil
I checked switch positions so that’s done, I will have a try with the short address on Monday, just left railway.

 

[LGB333]

I had some time so I came to the railway this afternoon.

Cab removed and sound unit and rear lights unplugged.

On programming track loco responds to CV reads and writes. loco judders and moves along the track, lights disconnected.

CV 17. 203
CV 18. 189
CV. 29. 34

Loco No. 3005

On main track loco doesn’t respond to throttle.

I thought about a decoder reset , is there a risk of decoder putting full voltage on lamps after reset?

Power is being drawn from track and motor seems to be OK. Am I looking at a new decoder?

Robin

The 55021 decoder is very old DCC technology. Since the User Guide I posted doesn't even show settings for long addresses (CV29/17/18) on the Register Listing, I'm not sure long addresses can even be used with it. I'd suggest you set the decoder for a short address and try it. You'd set CV29=6 and CV1= 3. The User Guide says the CV1 range is limited to 00-22.