PIKO Digital Steam 36220 issue

David Peacock

David Peacock

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Greeting all.
First time user here.
I recently installed the PIKO digital american steam sound 36220. And i love it.
But oddly , at slow speeds when the bell or whistle is activated, the engine slows down a tad. (see video)
Should i add a cap bank?
Thoughts?
 
Also details of the decoder fitted (PIKO as well?)
IIRC PIKO decoder and digital sound are rebadged Massoth (motor decoder) and Uhlenbrock (sound module). If so the sound module is connected via SUSI so the power for the sound module and the sound generated comes from the motor decoder I guess it's possible at low speed pulling a long load as shown that a small drop in power available to the decoder would cause the loco to slow down a tad. But a lot of this is conjecture without the relevant data. My two cents, Dave
 
idlemarvel said:
Also details of the decoder fitted (PIKO as well?)
IIRC PIKO decoder and digital sound are rebadged Massoth (motor decoder) and Uhlenbrock (sound module). If so the sound module is connected via SUSI so the power for the sound module and the sound generated comes from the motor decoder I guess it's possible at low speed pulling a long load as shown that a small drop in power available to the decoder would cause the loco to slow down a tad. But a lot of this is conjecture without the relevant data. My two cents, Dave
Click to expand...
Yeah the PIKO digital sound card is also a dc/dcc decoder, but im using it simply on a DC loop.
Guess ill have to go though my wiring again.
Could the neodymium magnets be causing some problem i wonder? could they be strong enough to be changing the magnetic field of the engine ???
 
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I guess if you're using DC the bell/whistle is being triggered by magnets in the track. I've not heard of them slowing down engines before but I guess it is possible.
 
More likely to be a power pickup problem, I would have thought??

How do you feed power to the track? - I am thinking you have two slightly dodgy track-joints, either end of the area it slows down.
 
It really does look like the train slows when the whistle is blowing, and it does indeed NOT look like power or curvature related, judging by where the loco was each time the whistle blew. Both times it appeared to me to speed up as soon as the whistle sequence ended.

I'd repeat that test on a small loop of track where you can keep the loco (by itself) in camera all the time.

Weird! (what is triggering the whistle? magnets?)

Greg
 
I was going to say, that is quite a train it is pulling..
Loco on its' own, as Greg says.

?Bad pickup / high resistance, between track and decoder, perhaps?
 
idlemarvel said:
... I guess it's possible at low speed pulling a long load as shown that a small drop in power available to the decoder would cause the loco to slow down a tad.,,
Click to expand...
This isn't the cause, I tested on my Uhlenbrock sound module and there is no discernible drop in power (less than 0.01A) whether the sound plays or not.

Does the train slow down over the magnets when the sound is turned off?
Maybe the bottom of the power blocks is dragging on the magnets?
 
hard to believe it is a power issue, 10 amps confirmed, decoder could not be putting out more than a watt, with an efficient class D digital amp that is less than one tenth of an amp.

Also, the decoder is microprocessor based and it runs from a regulated supply, the motor is run from switched power from the rails, even in DC mode... so something is changing the PWM signal to the output transistors, and that signal is a frequency not a voltage.

hmmmm...
 
Greg Elmassian said:
hard to believe it is a power issue, 10 amps confirmed, decoder could not be putting out more than a watt, with an efficient class D digital amp that is less than one tenth of an amp.

Also, the decoder is microprocessor based and it runs from a regulated supply, the motor is run from switched power from the rails, even in DC mode... so something is changing the PWM signal to the output transistors, and that signal is a frequency not a voltage.

hmmmm...
Click to expand...
maybe ill give weaker magnets a try. those neodymiums have a very large field.
 
idlemarvel said:
Does the train slow down over the magnets when the sound is turned off?
Maybe the bottom of the power blocks is dragging on the magnets?
Click to expand...

I'm going to try that right now. will post results

*Update*
OK with the sound completely turned off, the stall does not happen. The hesitation becomes more noticeable with Volume increase.
Is it even possible the 8ohm 3 watt speaker could really be robbing the system of that much power?

I got a chuckle because this has reminded me of what a friend once said to me many years ago "Lionels aren't designed to run slow" maybe he was right LOL :D
 
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The speaker only uses the power given to it, it does not "suck" 3 watts out of the amplifier.

But the amplifier is rated at 3 watts.

Again picking 12 volts as an approximate voltage you are running, that is still 1/4 amp... still very hard to believe that your track voltage could be affected, but this is easy...

Run the loco alone
set your throttle.... leave it there
run loco with sound and measure track voltage before and after whistle blows.


This simple test will tell you if it's a variation in power to the decoder.


Again, I'll bet it is a problem in the decoder... these things work on microprocessors... perhaps poor coding or a bug that causes this issue.

Greg
 
Greg Elmassian said:
The speaker only uses the power given to it, it does not "suck" 3 watts out of the amplifier.

But the amplifier is rated at 3 watts.

Again picking 12 volts as an approximate voltage you are running, that is still 1/4 amp... still very hard to believe that your track voltage could be affected, but this is easy...

Run the loco alone
set your throttle.... leave it there
run loco with sound and measure track voltage before and after whistle blows.


This simple test will tell you if it's a variation in power to the decoder.


Again, I'll bet it is a problem in the decoder... these things work on microprocessors... perhaps poor coding or a bug that causes this issue.

Greg
Click to expand...
Thanks Greg, Will try that.
Iv'e also notice that the brake squeal also sounds when that happens, so the card must be registering a voltage drop of some sort.
 
David Peacock said:
Thanks Greg, Will try that.
Iv'e also notice that the brake squeal also sounds when that happens, so the card must be registering a voltage drop of some sort.
Click to expand...

There isn't some sort of detection circuit for an accessory is there??
Could this be 'brake on DC'??
 
As John S started to mention, I believe you might have a power supply that is NOT considered pure or well-filtered. (A well-filtered power supply is more expensive.) Piko seems to use a well-filtered and pure DCC on their systems. I believe the only pure DC systems are Piko, LGB, and Bridgewerks. I have the Piko system and it is "pure DC". The other companies say they have pure DC, and i have heard good things about Bridgewerks power as well.

By the way, did you call Piko about this? They have been able to walk me through the questions I had and were nice, and easy to reach. (Had other companies I was never able to get a hold of! You know, "oh, you need to call person X". Call person X, "oh, you need person Y" etc. etc. ) Piko pickup up right away. (Well, after the office opening on the west coast)
 
I'm using 14 gauge at 18 inches soldered to track. power shouldn't be an issue as i don't use the Variable Momentum or Braking Control features because it's just too inconsistent with the various engines i run.
 
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