Resulting from customers building experience on several Matrix Ctrlr, here are the common possible problems you could encounter and their symptoms/solutions. It’s a good idea to use sockets for ICs as this allows you to swap a component by another one (there are usually several same units on the Kit for a given value) and decide whether or not it’s defective.

It’s also a good idea to check your soldering first as it is the main cause of trouble.

All LEDs have been tested before shipping (to sort them regarding their dimming characteristics). ICs have always been protected in antistatic containers. Other components have been stocked in antistatic drawers or boxes (no plastic bags).

It appears that some 74HC165s from the first batch are randomly defective (certainly a factory bad batch) after several hours of use. Here is a screen shot :

It’s strongly advised to use sockets for those shift registers in order to swap them for new ones when needed, in the future.

Random messages on screen corresponding to potentiometers parameters controls :

  • one or several pots are defective (stress while snapping caps) : replace for a brand new pot
  • bad or missing soldering on pot terminals or CD4051 : solder better !
  • wrong orientation of CD4051 : remove and replace (swap with another one available)

LED not working :

  • wrong orientation of LED : desolder and solder it right back
  • attached RLed badly soldered (cold solder joint) : better solder
  • check soldering on 74HC595 pins

Switches not working :

  • check soldering of switches and 74HC165 sockets.
  • 74HC165 defective : replace it.

MIDI IN not working :

  • check 6N138 orientation
  • check D18, D35 orientation
  • replace 6N138 (swap two units)

LCD not working :

  • check soldering of P1 (critical step) on the LCD and on the Mainboard !
  • check orientation of LIGHT1 and CTRST1 trimmers regarding their footprint. If you invert them they still work but clockwise turn becomes counter clockwise turn.
  • check PSU and voltages on Ctrlr : +9V DC on input and +5V DC on board.

I had fried the voltage regulator of an iDuino Mega using another old power supply brick wall. The LCD was completely white (too much contrast and voltage on board was 12V). The Ctrlr had an erratic behavior. But the iDuino was still working by USB supply after that ! From this experience, i can tell that the Matrix Ctrlr is rather resistant to voltage stress as nothing was defective after iDuino board replacement.

The PSU furnished by Alpes Machines is new and good quality. The one of your Guitar pedals could be hazardous …

Recent Posts

Matrix Ctrlr 1.38 update

There is a long time we have published some news !

We (or should say “I” as alpesmachines is a single guy project) have been focused on daily life things and a regular job but some prototyping projects should be exposed in the next weeks …

We have also invest some time to enhance the Matrix Ctrlr and you can find the latest revisions 1.38 on Github here :

  • One major improvement is a faster display librarian : all the micro delays induced by printing on the display have disappeared. You can trigger very short notes and move all the parameters together now : beware to the musical results !
  • ARP Menu : now you can set the split point in between the arpegiated section and the sequenced one with a midi learn : simply press KEY2 under SPLT and send a midi note to define the split point. A customer request !
  • We have also improved the ADC stability by using a moving average method to filter power supply noise and thus having a more stable reading of the potentiometers. It can be access under the CFG/MISC/JTR parameter. A lower value uses lots of filtering (drawback the calculus is longer so the printed value is a little delayed) while a higher value is more responsive and sensitive to noise. The value can be set by pressing KEY4 and saved with PAGE. Now you can use a very bad quality power supply if you like.

We still have a few kits in stock and you need to order a Matrix Ctrlr ECO kit + assembly service to have a ready to use unit.

We recommend to have firmware 1.20 or 2.15 inside your Matrix 1000 or Matrix 6 : we provide Oberheim EPROM if necessary.



There are also Stereo One-O-Six Chorus kits in stock, a nice companion to add wide stereo effect to a mono synthesizer !

We wish you all the best and enjoy the unlockdown freedom !



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