Hi guys

I've just converted my 3075 (LFCM) with a HAMO magnet and a decoder from the Fire Brigade 211 loco (which I believe to be similar to a 60902, but with on-track programming).

The loco runs beautifully in analog mode at all speeds. However, in digital, any speed below "100" on the 6021 dial results in terrible "stuttering", and at the lowest speed setting, is runs with horrible jerks.

I have a suspicion that it's about the chokes/capacitors that are/were installed. I left in place the 2 chokes between the decoder's blue and green wires and the motor connections. I also left the capacitor between the two motor connections, but I don't know if it's the right capacitor for digital operation. I DID remove the capacitor that used to connect the right motor connection to the soldering point on the motor block.

Questions:
- are there any reasons why HAMO + 60902 (or similar) shouldn't work?

- do I need a different value capacitor between the two motor connections?

- do I need to re-instate the capacitor that I removed?

- do I perhaps even need a third capacitor from the LEFT motor connection to the chassis?

I've seen many different variations, and I'm just not sure which is the right one! So - help!

Yes, there is a reason why this happens. The 60902 decoder is made for the high-efficiency motor parts (5-pole rotor and the small but very powerful neodymium magnet). Using other motor parts (like the HAMO magnet), the voltage feedback from the motor will be different, and the decoder won't know how to regulate it properly.
It's only a guess, but I think this is why you see this jerky behaviour.

OK, so SRB is saying that I need to have capacitors between ground and each brush, and Jorge is saying they need to be removed! I'm confused...

Is there really NO way of using the Fire Train decoder with HAMO?

If that's case, are there any suggestions other than LoPi? Do Uhlenbrock have any suitable decoders (I want load regulation)?

Hi,

I have just done two conversions with Hamo magnets with three pole rotors. You must change the load regulation CV values.

Try these:

CV 2 = 6; (starting voltage)
CV 53 = 14
CV 54 = 20
CV 55 = 15

If afterwards the lok drives too slow, try raising CV 55 to about 25. Experimentation is the way to go. Be sure to take note of what you change and change only one CV at a time, try the lok at different speed steps to see what changes and if it pleases you.

Luis

My recommendations were based on Richard saying it was the on-track programming version of the Feurwehr BR212. That decoder is a Lopi v2.0, and he can program it with a mobstat, under the REG option or following the normal CV programming procedure for a 6021.

Luis

Update:
I have just completed a different conversion; a 3072, LFCM with HAMO, and a "proper" ESU-branded Lokpilot 2.0. The driving characteristics are almost as good as 6090x, so I'm very happy.

This leaves the question why the Feuerwehr decoder cannot run my other LFCM HAMO motor properly. I've tried playing with the CVs, but these have had no effect whatsoever. I've also found this:

https://www.marklin-user...ault.aspx?g=posts&t=1949

which suggests that I might be dealing with a "dumbed-down" version of the Lopi instead of the "full" version.

Anyway, as it stand now, I'm left with two options:
- upgrade the motor to 6090x high efficiency propulsion [:p] (I can hear all of you shout "go-go-go!" already )
- rip the decoder out and replace with with one of the offerings from UB, ESU & Co.

I'm both lazy (don't want to redo all my soldering/cable laying) and tight when it comes to money (don't want to pay for a new motor, especially since my other conversion has proven it can work). Furthermore, it's an older loco, and I'm reluctant to spend more on the upgrade to digital than the actual loco is worth in the first place (the famous car stereo issue ). Has anybody actually ever run a Marklin 60902 or MFX decoder with a HAMO motor?

Small note:
if there is space, I suggest using NMRA plugs. Takes care of much of the 'lazy part'... Easy to switch decoders, and make tests.
/Lars

Hi John, and thanks for the advice. I've used the predecessor to the UB 76200 in two of my locos, one LFCM, one SFCM, and am also quite happy with the results. I do find the motor a bit noisier than my LFCM HAMO, though.

Lars, thanks for the tip with the NMRA plug. I've used the 8-pole NEM plug/socket in my V100, and - space permitting - will definitely go for this approach again.

I am tempted to go for an ESU Lokpilot in this case. First, it works great with the LFCM HAMO and is a bit smoother than the UB 75200/76200. And second, I can get it with the NEM plug already connected, saving me the work (did I mention I'm lazy ). But then there's the UB 76420 which also has a plug... Decisions, decisions...

Any ideas who has made the decoder then

Stig

Thanks Fred, much appreciated. Looks as if the Feuerwehr decoder, for whatever reason, really only works with a high-efficiency motor. I'll certainly give the UB decoders some thought.