Lais DCC

[Zorcan]

I've just fitted one of these Laisdcc decoders into a Bachmann GP40. It works fine if I don't change the factory settings, and the loco runs as smoothly as you'd expect with 28 speed steps. But if I set it to use speed tables for a smoother speed curve, by setting CV29 to 22, it's not happy at all. It crawls along very slowly till the throttle is at about a third, then it puts on a sudden burst of speed. The opposite happens when it slows down.

 

I tried programming a straight line speed curve into CVs 67 to 94, just to see if the factory-set one was faulty, but no difference.

 

I didn't notice a capacitor in the loco to take out, and in any case presumably if that were the problem, it would show itself regardless of whether I was using speed tables.

 

Has anyone else had this problem? Is there some other CV I need to set?

 

I've just fitted one of these Laisdcc decoders into a Bachmann GP40. It works fine if I don't change the factory settings, and the loco runs as smoothly as you'd expect with 28 speed steps. But if I set it to use speed tables for a smoother speed curve, by setting CV29 to 22, it's not happy at all. It crawls along very slowly till the throttle is at about a third, then it puts on a sudden burst of speed. The opposite happens when it slows down.

 

I tried programming a straight line speed curve into CVs 67 to 94, just to see if the factory-set one was faulty, but no difference.

 

I didn't notice a capacitor in the loco to take out, and in any case presumably if that were the problem, it would show itself regardless of whether I was using speed tables.

 

Has anyone else had this problem? Is there some other CV I need to set?

 

Yes - I've had several similar experiences. They ranged from minor undue speed variation in one model through extremely zealous down-slope acceleration to violent stop-start jerking in others. In all cases, I had not removed all the motor suppression capacitors. In all cases, doing so fixed the problem.

[Zorcan]

Yes - I've had several similar experiences. They ranged from minor undue speed variation in one model through extremely zealous down-slope acceleration to violent stop-start jerking in others. In all cases, I had not removed all the motor suppression capacitors. In all cases, doing so fixed the problem.

I should have added that I've not attempted to set any speed curves.

[alfsboy]

I fitted a square laisdcc 8 pin into a Athearn Genesis GP7 SP black widow .This is simple fit so worth spreading the word on a tricky loco to install a simple  decoder in space wise.It all works fine except the top two christmas tree lights dont work .The rear ones do  work as per spec. The lights all work fine   if the 8 pin decoder is removed and the 9 pin JST  blanking refitted .Any ideas out there ?.It all works well apart from that .

martin

[RAF96]

@post #28

Check that your lights current draw isn't outwith the decoder function output capability. If so bung a 1K ohm resistor in the blue wire to drop the overall functions current.

Rob

[Phil S]

Do the missing lighs require the 4th function output?

[spice1977]

When I first saw these on eBay I bought loads of them both 8 and 21 pin (at least 50 of them). Not had any issues with the 21 pin ones and all still installed but have had quite a few 8 pin ones blow for no apparent reason other than perhaps because they were fitted to older converted Lima & Hornby stock. I too was offered a sales pitch which I also ignored.

 

Anyway I have stopped buying them now for those reasons as every time one goes its £10 down the drain and I am now fitting DCC Concepts zen 8/21 pin decoders to cheaper locos (which are all working fine and very versatile at £17ish (and come with stay alive supplied) a pop from Time Tunnel Models or Hattons own brands (as low as £12 each if bought as multipack) and keeping the high end ones i.e. Lok, Lenz and Zimo for highly detailed / expensive stock with the advantage of UK based support if it all goes wrong. To all others I fit decent capacitors for stay alive function.

 

Lais ones in my own personal experience don't cope well with older locos that draw higher current but do work ok in more modern loco drives and since I like to update older locos occasionally I won't be buying anymore. Just from my own personal experiences.

[Tankdave]

I have a bought a few 8pin ones and find them inconsistent when setting top speed, they change from one running session to the next "on the same loco" and when loco's accelerate they get to about 3/4 speed then take off like a scalded cat.

 

I have since been using the Hattons £10 ones and they are much better, I will use the Lais ones I already have in my DMU "dummy" power cars, they are fine for that.

[alfsboy]

I bought this one to put a brass SP 2-6-0  that I want to  paint and sell  .They work well enough for me on  my small  layout  with just motion and lights  in brass loco's .It only ended up in the GP9 as it fits easily into the dynamic brake pod being  small and square .Probably needs a larger function decoder but as its going to get a WOW  sound in the end its not worth buying a better DCC decoder  I dont need .i set the brass up with an 8 pin socket in the tender  so that a sound decoder can plug and play .The Laisdocs just prove it all works OK .

thanks for all your comments .

[njee20]

Still using a number of the 6 pin ones as function decoders, with a few doing motor functions too. Seem fine, never had one blow. About half the price of any other 6 pin decoders, so they still have a place.

 

I get a personal email from them every couple of months asking if I want more. I suspect their customer base isn't that big!

[Zorcan]

I have a bought a few 8pin ones and find them inconsistent when setting top speed, they change from one running session to the next "on the same loco" and when loco's accelerate they get to about 3/4 speed then take off like a scalded cat.

 

I have since been using the Hattons £10 ones and they are much better, I will use the Lais ones I already have in my DMU "dummy" power cars, they are fine for that.

 

Hi Dave - do you remove all the interference suppression capacitors from your locos when fitting chips to them? - failing to do this can distort the EMF feedback signal to the decoder and so upset speed control. Just a thought . . .

[RFS]

I have a bought a few 8pin ones and find them inconsistent when setting top speed, they change from one running session to the next "on the same loco" and when loco's accelerate they get to about 3/4 speed then take off like a scalded cat.

 

I have since been using the Hattons £10 ones and they are much better, I will use the Lais ones I already have in my DMU "dummy" power cars, they are fine for that.

 

I had the same problem a few years ago when using some TCS decoders: for example, with one loco using 28 speed steps I was able to record a scale speed of 81 mph at step 28, and 87 mph at step 26. Plus there were variations between running sessions. The firmware in Lais decoders is allegedly "derived" from TCS which might explain why they show the same characteristics.  I now use Lenz and Zimo decoders exclusively. Yes they cost a bit more but you get what you pay for, and Lenz and Zimo they are top quality plus they have overload and short-circuit protection.

Edited March 19, 2017 by RFS

[big jim]

When I first saw these on eBay I bought loads of them both 8 and 21 pin (at least 50 of them). Not had any issues with the 21 pin ones and all still installed but have had quite a few 8 pin ones blow for no apparent reason other than perhaps because they were fitted to older converted Lima & Hornby stock. I too was offered a sales pitch which I also ignored.

 

Anyway I have stopped buying them now for those reasons as every time one goes its £10 down the drain and I am now fitting DCC Concepts zen 8/21 pin decoders to cheaper locos (which are all working fine and very versatile at £17ish (and come with stay alive supplied) a pop from Time Tunnel Models or Hattons own brands (as low as £12 each if bought as multipack) and keeping the high end ones i.e. Lok, Lenz and Zimo for highly detailed / expensive stock with the advantage of UK based support if it all goes wrong. To all others I fit decent capacitors for stay alive function.

 

Lais ones in my own personal experience don't cope well with older locos that draw higher current but do work ok in more modern loco drives and since I like to update older locos occasionally I won't be buying anymore. Just from my own personal experiences.

i bought a few of them via ebay, mainly fitted to Bachmann 66s and 37s with no adjustments carried out, most run well (4 or 5) whereas one is bit erratic, a loco will be moving along nicely then just quickly change direction (as can be seen by the headlights/tail lights changing) and back again, the loco normally comes to a brief stop before zooming off at whatever speed it was set to originally (ie with acceleration curve disabled)

 

the function only one i fitted to by converted DBSO coach appears to have lost a function (tail lights wont come on any more ) but ive not really looked into it or tried a reset, may just be my hooky wiring

 

despite the above problems i probably would use them again in cheaper locos but stick to better brands for my more 'prestige' locos

[LongfordLad]

I've now converted five locos to DCC using the LaisDcc decoders. All are working fine. These decoders are pretty functional, with various settings for lighting and back EMF. The only problem I had is that the back EMF, which is enabled by default, goes a bit haywire when you enable the speed table. So either you do without the speed table, or you disable BEMF.

 

I daresay the BEMF settings can be tweaked to get round this, but I've found that I don't really need to use the speed table, there's enough fine control by using the various motor voltage CVs.

 

The supplier I bought the decoders from has pointed me to the LAisDcc user manual, just released recently:

 

http://tiny-smart.com/LaisDcc_Decoders_Manual.pdf

 

Thanks for the info. I'd been struggling with this on the first loco that I've ever converted - on which I used a LaisDCC decoder.

As you said, it functioned OK at low speeds but as the throttle was edged open, it would suddenly take off like a scalded cat. (Am I still allowed to use that metaphor? Sorry if it offends anyone.)

I tried setting CV 61 to zero but that didn't help. However, subtracting 16 from CV 29 to suppress use of the speed table seems to have done the job. 

I'd bought a few of these decoders as a batch, so I will now try out the others.If they show similar issues, I will move up market.

 

John

[Junctionmad]

I seem to remember they have a bug , that requires the Bemf to be turned off

[alfsboy]

I use em in US brass  steam and plastic diesels and have no problems with them .I use a Tech 6 black box  as I only have a switching layout unless I set up an on floor roundy with Roco Geoline .i have also tried them in UK plastic  locos and they work fine so far ,So   far  3 hours  is  the longest I have run one continuously  on the floor and no problems .Wish they did a cheap US  steam sound decoder  or for that matter Hornby did one