MUX_SH board mod tutorial

Discuss Nava construction and related issues
  • Ok found the problem. :geek:

    Short on the 15v+ rail. :oops:

    No idea where it is or how I did it but obviously I have bumped something while doing the mod or opening up the NAVA.

    I've removed the Header, 2x MUX Boards and all the connector headers to the I/O Board. Short remains.

    Anyone got a good/fast way to find a short to a power rail?
  • Of course no...

    Disconnect related things which are easy (and safe) to do to see if it reacts different. Follow the traces thanks to the pcb layout pdfs and check for wrong continuity along them.

    But how do you know it's a short ?
  • gihaume wrote:But how do you know it's a short ?
    Because there is continuity between 15v+ and GND.
    AND when I connect the I/O board to the main board, there is no 15v+ at the I/O board 15v+ header.
    When I remove the connection (Between the Main and I/O boards) 15v+ returns to the I/O board.

    It is either a short with a bent over component or a shorted out component. Either way there is a short to GND on the 15v+ rail.

    I will try pulling out IC's to see if the short is there tomorrow. :x VERY annoying.
  • +- 15v comes in at the 0ohm resistors. Pull these one at a time and check voltages until it comes back. Then you should at least be able to pinpoint to a single circuit.
  • serum114 wrote:+- 15v comes in at the 0ohm resistors. Pull these one at a time and check voltages until it comes back. Then you should at least be able to pinpoint to a single circuit.
    Good Starting point to pinpoint the areas of the PCB one at a time serum114! Thanks :)

    Digital sections and Sequencer are the only sections/areas that use 15v+. Yes?
  • I think there is a couple of ics using 15v but youd have to check the markings on the board to confirm and of coarse the schematic as its also the transistors using the 15v rail
  • Found the short. Was on the secondary noise source PCB. I had a metal stand off that was shorting GND and the 15v+ power rail on the noise PCB.

    MUX boards work.
  • Is there any shematic of these mux boards? I sold 6 pairs, only 2 work completely. I would like to understand for reasons that the other 4 kits do not work, knowing that the solder/built is identical ... Tried on nava V1.01 and V1.02, same results ...
  • Where can i find wich value's go where on the mux board? i have 100nF and 470pF value's in SMD components