Earlier Lenz decoders pre Gold/Silver introduction

[34theletterbetweenB&D]

I have a decoder in a s/h acquisition that tells me it is Lenz, (mfr # 99) but nothing like a Silver which it otherwise physically resembles for size.

 

The performance is most curious, (it's driving a free running Mashima that draws about 120mA max, 300mA stalled). Every now and again with no correlated activity on my part, while standing at speed step zero it makes a little grumbly noise, and jerks one way or the other. It runs the motor perfectly adequately most of the time, but will every now and again slow down to a crawl, then resume set speed. If you put in a large deceleration, it often goes well below the set step speed, and then recovers to the new slower speed step. No heating or anything evident on the deoder, stays cool to the touch at all times.

 

At first I wondered if I had pick up difficulties on the chassis, so took the worm off the motor shaft and hard wired the power to the decoder inputs. Still does all this funny stuff. Tried a Lenz silver mini on the chassis, which runs it perfectly normally and stably.

 

So, my question is whether this is simply normal on older decoders, or this is a failing decoder which I should bin rather than install as a function only unit for lighting or whatever. (It's not going to be controlling any motors ...)

[mikeg]

This sounds like a 1050 chip, I have one in a lima O class 33 and it can sometimes slow right down and then very quickly get back to the original setting. As I do not have a continous run and it happens when on a reverse curve I put it down to variable load on the loco, as both my other 33's with 1000 chips run ok with good motor control.

 

Have you tried measuring the function outputs as they are not variable with this chip as far as I know, so if giving 9-14v then I can't see any reason not to use them. My loco with the 1050 chip has acc & dec set to 0 as any value above seemed to make the running very eratic, but as I do not use any of the functions I can't comment on their use.

 

regards

 

mike g

[Phil S]

A question: Is this behaviour ALSO seen when the loco/decoder is connected DIRECTLY to the controller output - without track or other locos or accessory decoders affecting the quality of the signal? [This may have been what you meant with wiring direct to the decoder]

If you had an oscilloscope, I'd suggest looking at the waveform - again with and without the layout (I started doing this with Zero-1) ......

 

LATER [Lenz] decoders, especially those including the ability to run over 'dirty track' through edge detection of the signal (and a power resever when added) may be affected differently to older simpler 'level' detecting decoders .... and designs inbetween may have differing amounts of 'noise immunity' built in by the way they process the signal.

I'm assuming the direct controller output is producing a perfectly clean signal, which may be adversely affected during distribution. (if the problem disappears on direct connection)

[34theletterbetweenB&D]

As you surmise it has had a direct connection from the Lenz 100 command station to the decoder. It does all the funny stuff regardless of whether it is the only decoder connected to the command station (layout disconnected) or when operating half a dozen or more locos on the layout. I cannot correlate the 'funnies' with any other actions. Unfortunately my 'scope is 200 miles away, since my Pa's 'scope blew its tube...

[Mike Friedman]

Your problem is not typical in my experience.

I still run over 20 of my locos with Lenz LE 1025 decoders as well as two with LZ 103 and one with an LZ 113 and have not experienced the problems you mention.

 

Controller is a Lenz LZV 100.

[34theletterbetweenB&D]

Thanks Mike. With zero prior experience of decoders before the Gold/Silver range was introduced I thought it was worth asking. It's going to be used as a function only decoder to power lights in a DMU trailer car. Don't often run the lights so not bothered if these are not terribly reliable, the function output voltage droops off too when the motor output randomly goes low, so it's the whole decoder's power output regulation that's flaky. Perhaps it was 'abused' in its earlier life and is in a gradual decline...

[34theletterbetweenB&D]

And while fiddling about to install it, the grey wire fell off. Neatly tinned wire end came completely free from the solder pad leaving a little hole through it. So, a dry joint. Resoldered it has a trouble free motor drive after an hours testing; previously it was throwing off a 'funny' every minute or two, so feel pretty confident that has fixed it. Presumably a bit of rectification or just variable resistance in the motor path causing the decoder to act up.