The latest stuff done

Fix dead buttons on a Roland MC-303

Long time ago, my main sequencer for musical excursions were the Roland MC-303. Maybe not the best in the world but sure did function well enough to have a lot of fun with. So, when a unit appeared for sale on the second hand market, I bought it.

To my great disapointment, the Swedish Postal Service ("Posten") did it´s worst to kill the unit. But instead of going to the complaints department I ripped it open to find the fault.

What was dead? Some very important buttons were completely unresponsive. The green circles shows which ones.


The schematic clearly showed were to look if you consider which buttons that were dead. The wiring shows a normal way of scanning a lot of buttons using som logic.


And what did I find? A small crack on the PCB, just behind the "TAP"-button. It cut the PCB traces as shown above in the schematic.


And the fix (quick and dirty). The MC-303 now works perfectly.


How to repair broken glasses

Some people need glasses, and I am one of them.

Sometimes they are destroyed, and it´s very annoying to wait up to two weeks for new ones (and also manage to find time to meet the optician during busy days).

One of the most regular incidents is that the side pieces breaks, which incidentally happend to me the other day.

How to repair broken side pieces?

Heat shrink tube! And as I am doing electronics I always have tube available in several colours. Black seemed to be the choice, but green/yellow (earth) would look nice.

large_repair glasses withy shrinking tube.jpg


2N2222A fuzz, nice for x0xb0x

Well, a simple circuit. One transistor! Almost any transistor will work. In this case, an old transistor was used - the 2N2222A.

The schematics:

medium_2N2222A fuzz_schema.jpg

Video: First without fuzz and then with fuzz. X0xb0x serves as sound source.