Over the weekend i installed a new 60901 into a 3309 (DB 85 Class) that has smoke and telex. I wired up the smoke unit to F1 and the front and rear telexes to F2. The lights were connected to Function.

I knew that I would not be able to check the operation of F1 and F2 with a 6020, but I was amazed to see smoke coming out of the funnel as soon as the loco was put on the track. It appeared the F1 was active immediately - even without addressing the loco. Interestingly, the telex via F2 was off.

I took the loco to a friend (just outside of the Shire) and we confimed that all functions and lights works perfectly when using a 6021. We made sure everything was set to "off" when we finished. However back home the smoke unit started producing smoke again as soon as the loco was put back on the rails.

Is this normal? That is - is F1 always "on" when used with a 6020, but F2 is "off"?

A little surprised but only little. These decoder have some kind of default setting which means that in analog f1+function is on, rest is off. I guess this is what happened. As the decoder detects Motorola old, it realizes it will never receive understandable f1-f4, so it uses the default setting. I can't tell if it's 'normal', nevertheless, I find it 'understandable'.

/Lars

No,
not switch, as Telex is the other function. Never attach Telex to f1 for obvious reasons!

It seems that F1 is also on if you set your Intellibox to old motorola protocol - that's what happened to me recently.
Years ago I must have set address 78 to old motorola protocol in order to program one of those jumperless decoders.
As soon as I selected that address on my 6021 (connected as a slave to my IB), F1 was on and could not be turned off.
I realized this as I selected that address on my IB (protocol shown on display).

(Edited) AFAIK Function and F1 will always be on if you use a Delta Station; with a Delta Control 66045 Function can be switched and F1 is always on; with a Delta Control 6604, Function cannot be switched (and is probably always off), but F1 is always on.

Please see: http://www.maerklin.de/faq/download.php?Number=50

and: http://www.maerklin.de/p...e/digital/h0-decoder.php

"Im konventionellen Betrieb oder im Betrieb mit der früheren Central Unit Art.-Nr. 6020 oder mit Märklin DELTA sind bei diesen Decodern die Funktionen <<functions>> und <<f1>> immer eingeschaltet. "

Regards,
Lutz

Great feed-back. Thanks.

One wonders why M did not default F1 to "off" as a precaution (like with F2). Certainly someting to be aware of when running newer locos on 6020 based layouts. Prolonged and inadvertent use of F1 is probably not healthy for either decoder or the smoke unit - especially if run dry.

Looks like I need to disconnect the smoke until I upgrade the 6020.

Perhaps Gandalf did indeed work at M at some stage. Certainly an endless number of digital mysteries point to it!

Since the only switchable function with the 6020 is the "function" could I connect the two Telexes to the light outputs (grey and yellow) without blowing the 60901 decoder?

How much current does each Telex device draw? And do all Telexes draw the same current, or are there differences?

Obviously I would have to forget about lights and smoke on this loco in order to be able to use Telex, which I accept.

Maybe the following helps - taken from: http://www.maerklin.de/p...e/digital/h0-decoder.php

"Vor dem Einbau sollten Sie sich genau überlegen welche zusätzlichen Funktionen angeschlossen werden sollen. Bitte bedenken Sie immer, daß im konventionellen Betrieb die im Digitalbetrieb unter <<function>> und <<f1>> geschalteten Funktionen immer eingeschaltet sind. Daher ist es nicht empfehlenswert, eine Telexkupplung oder einen Lokpfeifengenerator an eine dieser beiden Funktionen anzuschließen."

Translated it tells the following:

"Before installation you should carefully decide which additional functions should be connected to the decoder. Please keep in mind that the functions <<function>> and <<f1>> are always turned on in conventional operation. Therefor it is not recommended to connect a telex coupling or signal horn generator to any of these two functions"

There are differences in the current consumption of the various telex magnets. Also a telex magnet is a coil and generates an inductive current, oppose to a simple resistor or bulb. This could or even will blow the 100mA direct function output of the decoder, whereas the additional functions are switched by separate transistors with a maximum current of 250mA.

Just go the safe way. If needed install an addidional power transistor or relay in order to protect the decoder against undesired damages.

Regards,
Lutz