[Triaxis] Buttons don't respond

[comp]

Greetings,

I have Triaxis + 2:90 rig and experience two problems:
1. All the buttons on Triaxis don't respond. The only thing that works is the volume knob.
However, the MIDI Footswitch works fine and I'm able to switch presets. But I can't adjust them manually because none of the buttons work.
I have the system wired according to the Scheme 1 in the manual.
I tried to disconnect all the cables (except power), but the buttons still don't respond. The FX Loop light is lit even though all the cables are disconnected.

2. Another problem:
The volume is dropped by 60-80% after 10-15 minutes of playing. So that you start with the loud guitar and in 10 minutes the volume suddenly decreases.

Any ideas how to fix 1 and 2?
Thanks!

 

[a2dconverter]

Greetings comp

both problems may be related, but, the button problem is most likely a mechanical problem around the button membrane switch and the level drop is probably a failing LDR or tube.

If you have access to open the Triaxis, you will see where the front membrane switch connects to the circuit board...I don't have a picture of that, but, here's a pic of a defective membrane switch showing part of the blue connector that might have been dislodged.

otherwise, unfortunately, it sounds like your Triaxis will need a visit with MESA techs.

I hope this helps

seeya

Joe

 

[Ricotjuh]

A late response, but I also have the same problem.
I was able to take over a Triaxis with the following problem:
The display does not respond to the buttons. So all parameters remain unchanged when one of the buttons is pressed.
As far as I have tested, the Triaxis also does not respond to my midi signals from my Kitty Hawk foot controller. But I don't know if this is related to each other.
But what I want to start with is to get the buttons on the front panel working again.
Has anyone experienced this before? Because is it the buttons that do not work or is it possible that the display does not refresh? I would like to hear your findings.

 

[Ricotjuh]

I had just started measuring and I noticed the following. The 5V controller (7805) became very hot. +/- 60 degrees Celsius compared to +/- 40 degrees Celsius of the 7905. I found this remarkable. Therefore dismantled the metal shield of the CPU. I noticed that the TL7705 looks suspicious. Primarily the corrosion around the pins. I also do not measure 5V on pins 1 and 8. I do measure 5V on pin 8 and gnd elsewhere on the PCB. I think there is a good chance that the error is here.

 

[Ricotjuh]

Stupid, ... Power supply of the TL7705 is on pin 8 and 4. Here I measure 5V. So the power supply seems to be good. Still something has to go wrong in the 5V circuit since the voltage regulator gets very hot .. Investigate further

 

[Ricotjuh]

I finally succeeded in having the presets changed by removing the battery and completely discharging the capacitor. It has now shifted from "program" 25 to "program" 1. With the corresponding settings.
However, the problem persists that it is not possible to change the settings. However, I found out by switching the unit off and on once, that at some moments the unit does not start up completely. Most LED displays will then remain empty, the 'Dynamic Voice' will occasionally indicate 5.0 and at another moment only the dot between the digits of other displays. Furthermore, all the LEDs of the 'RHY', 'LD1' and 'LD2' LEDs are lit.
This seems to indicate that something is not going well during startup. I also find that voltage regulators that I referred to previously have nothing to do with the 5V that supplies the digital part with voltage.
This voltage is supplied by the LM323 so I will have to focus more on this. Still have the idea that something goes wrong in the "system reset" part. But I am not sure yet. But it seems that the program does not start completely and therefore seems to freeze. Attached is the video showing how the start-up goes wrong.

https://youtu.be/QnsjzrVo2MI

 

[Ricotjuh]

Bingo!
So far the problem seems to be solved. The device responds to all buttons and to my midi foot controller.
A faulty Z80ADART IC was the problem.