I recently upgraded my collection of interface boards VM110 from 4 to 8. I was a bit surprised to see that the new boards (VM110N) where very different from my old boards, even thou I ordered the old type VM110.
The manual ensures 100% compability between the two models so I decided to keep the new boards.
[quote=“VEL255”][quote]Does anyone know of similar issues?[/quote]Please see this thread: viewtopic.php?f=3&t=8108
May be similar issue and the solution.[/quote]
Indeed a very similar issue. I have exactly the same board and also these boards are likely to be from the first batch (summer 2012) before the different setup of the transistor was highlighted/known.
If I can find a spare 2N2222 or similar I will test tomorrow. Everything on these new boards is so tiny, so fingers crossed I don’t break anything.
Problem solved. Google tells me that the 2N2222 (used on VM110N) and BC337 (used on VM110) are counter opposites, and indeed this is the issue I have been struggling with.
I swapped the collector and emitter on the transistors T1 and T2 and voila, now PWM works
I am a bit disappointed that you buy a pre-assembled board, and it has been done incorrectly at the factory. The reason to buy pre-assembled is to avoid all the soldering. But you cannot argue with the results.
I decided to flip the transistors to the back of the board as the legs were too short to swap on the front side. It might not be the most esthetic solution, and from an educational point of view you can no longer see the transistors, but it works
This problem has been corrected a while a go.
Most likely, you have received a unit from a previous production batch, which has been sitting on the shelf at a local supplier for a while.
Anyway, we’d be happy to mail you some spare transistors.
Please let us know the qty. and your address.
Sorry for any inconvenience.
