Arachnid Mod Question

[jdduffield]

Hi. I’ve been trying to figure out how I can use the Arachnid to make a single-patch FV-1 without loading in all of the diodes. Instead of the rotating 8-mode switcher, I hard wired what I believed to be patch zero in the EEPROM bank. I’m new to this so what am I missing?

The schematic shows odd wiring for mode 1, which I assume corresponds to patch zero in the EEPROM bank (but not sure), … so, my thoughts are that the FV-1 translates that to mean “default to patch zero”. Is that incorrect? It didn’t seem like I’d need any diodes, but that may be where the breakdown is,… I’m not sure. If I need to load in some of the diodes, which ones? Thank you.

The dry signal works, but using the mix knob just mixes in some silence instead of the effect. I’ve tried loading the EEPROM up where every patch in it is the same effect. So, that rules out the possibility of it working as is for some other patch slot in the bank.

 

[falco_femoralis]

Yes, the rotary switch is set up such that in position 1, no voltage is sent to pins 16, 17, or 18, and none of the other modes are activated. I don't know which mode is the default one.

You shouldn't need the jumper you installed given that the first mode is selected by disconnecting power from any of pins 16, 17, or 18. Your jumper is making a connection but it's difficult to know which lead it's connecting to. If it's lead 2, 3, or 5, then the FV-1 pins 16, 17, or 18 could still be receiving signal even with none of the diodes installed.

Look up how to access the FV-1's built in effects so you can verify the FV-1 is operating properly and able to produce effect on its own. Unplug the eeprom chip just in case

Make sure your 3.3v regulator is outputting the correct voltage

Use the continuity function on your meter to verify that the eeprom chip pins have continuity all the way thru to the board. Those kind of sockets can be hit or miss

 

[jdduffield]

verify the FV-1 is operating properly

The FV-1 wasn’t soldered down completely I guess. I reheated and repositioned it and now it is working. I also removed the jumper. I am getting endless feedback but that may be because of either 1) the crystal got fried by the heat, or 2) the patch isn’t controllable by the potentiometers as is. I’ll simplify the patch first, ensuring control 1 and 2 only are used. If that doesn’t work I’ll look at replacing the crystal (or the cap next to it) and see if it got fried.