MK134 Steam Engine


I’m afraid I’m at a bit of a loss.

I built the steam engine when I apply power, well, it sounds nothing like a steam engine, I mean nothing; it’s more like… uhm, a buzzing but with Rhythm! Meaning, if I adjust the speed it get’s faster, if I press the whistle button it beeps.

So basically it’s acting LIKE it should, but sounding completely off. I suspect it’s possible I got a resistor wrong, although I felt I was pretty careful.

I used a 30w soldering iron.

Any suggestions would be appreciated.


A wrong resistor values can cause this behaviour.
Make sure to check other parts aswell.
Use a fresh battery.

Did you solve your problem? Mine is exactly the same, the right speed but the noise is only a very faint beeping.

Hmm, I also have exactly the same problem. Works as it should, except sound is only bleeping! I’m sure all components are correct. I purchased this from Maplin’s in the uk. Can velleman check the kit and confirm is does sound similar to a steam train please? Thanks

In fact, I have checked all the resistors, and confident everything is as it should be. Maybe there is an errata in the instructions? I can send you a photo of my board if you like.

I have checked the picture on maplins website, and also the picture on the packaging, and the components are different. My IC board was made in China (LM324N GK7381Aqv6 GK CHN) not malaysia, and the capacitors are different.

There is nothing wrong with the manual or the parts.
Please check your assembly carefully and use a fresh battery.

My kit was also bought at Maplins in the UK. It is a very well designed kit, very easy to make and it would be hard to assemble it incorrectly. I have checked that all the components are in the right places and it still does not make the right noise. Could Velleman not get a kit from Maplin and assemble it and see if it works? Perhaps the ICs or some other component are faulty?

ok, so I brought a new kit, I did two things differently.

1, - I reversed the resistors - ie the gold band at the beginning of the resistor, instead of the end (I’m sure this would make no difference!) - ie gold at the left instead of the right.

2, - I left LOTS of ‘leg’ on the capacitors and the transistors (I was afraid that I may have heat damaged them on my first attempt).

Results - I get a different noise. It is not like the ‘beeping’ experienced on my first kit, so something is better.

However, the noise, sounds like someone playing with the volume on a channel tuned to static, could possibly at a very long shot be described as similar to a steam engine, by a deaf person. The whistle, well, certainly not like a steam whistle.

I think this sounds nothing like a steam engine, and the variance is really poor. The whistle is nothing like a steam whistle.

For something that cost £8.00, you would be better off buying a children’s toy engine, and taking the electronics out of that.

If you have the same problems I did, I woudn’t bother buying a second kit.

This is a real shame. I really wish someone at velleman who had a 3 year old child waiting for sound effects for their model train tried this kit.

I’m looking forward to my trip back to maplins…

I too purchased the MK134 but from BGMicro in USA. Carefully assembled according to instructions and am experiencing the same problems: faint rhythmic noise and beep instead of whistle. I have checked,double checked, and triple checked component placement and polarity(where applicable).
I even checked for solder bridges between pads and found nothing askew. I suspect the IC but really wish someone at Velleman would investigate this kit problem and not give the “book” answer for fresh battery. I powered mine with a regulated bench supply capable of 5amps and set at 9volts with a DVM.

Thousands of kits have been sold, with almost zero returns.
The ‘fresh battery’-remark does make sense, as a weak battery causes the noise generating part of the circuit to behave erratically.
For us, it is difficult to determine if there is something wrong with your assembly or if you are simply expecting too much from a noise generating circuit built around a 324 op-amp.
If you could post a .wav file of the sound the kit makes, we could determine if it is OK or not.
Furthermore, you can always send in a kit to have it checked.

Thank you for the prompt reply. Can you give me specific instructions on where to send the kit to have it checked? I live in Texas,USA and can ship it anywhere but would prefer a USA location.

I’m glad I’m not the only one with problems with this kit. I am new to electronics and have successfully built one of the Velleman Xmas tree kits, so I thought I would try something more challenging. I too bought mine from Maplins in the UK. I have had some soldering problems which I consider I have resolved but am experiencing the same result. The whistle gives a single “beep” and the engine sound responds to the speed being adjusted but simply sounds as clicks. The volume control has no affect whatever. I tested mine with more than one new battery and a regulated power supply, but it makes no difference. I was going to buy another kit but thanks for the tip - I’ll hold on to my cash! :frowning:

docook, please check your email for USA service information.

For the record:
As we investigate all complaints about our kits, we’ve took a sample from our warehouse and assembled it.
It works as expected.

I am happy to report that the problem with my kit is now resolved. While checking for soldering issues one more time before sending kit in for repair, I found a pad had separated from the board and its trace. After cleaning the protective coating off of the end of the trace, I resoldered that leg of R-10 and the engine part of this kit now works and sounds great. The whistle still only beeps but I think more complex circuitry is required to make it more realistic. I only need the engine anyway in my application.
A 20 Watt iron was used for all soldering, so I don’t think too much heat was applied but can’t be sure.
All is well now and I am pleased with Velleman’s quick replies and helpful attitude. I will likely buy other kits in the future with confidence.

Well I’ve followed docook’s example and re-examined my board for the n’th time and after a few similar corrections eureka! it works - but I have a query. When the engine chuff is sounding should there be a background continuous steam hiss throughout the whole of the speed range? If not can you point me in the appropriate direction to investigate. Thanks for the forum without the help I would have given up on this electronics game - but my faith has been restored.

Yes, the background hiss is always present.

I have posted both my circuits on youtube

not working;


Aparantly the noise generating part of the circuit is not working or the noise is not coupled into the chopping circuit.
Check voltage over C8, should be more than 10V to generate noise. Check T3, amp circuit IC1B

Great, thanks for the help, Ill give it a second try.