# No wet signal on the new Arachnid MultiFX Platform



## MobiusOne (May 16, 2019)

I recently purchased two of the new version of the Arachnid PCBs. I'm not getting a wet signal from either one. I am getting the dry signal. I've tried trouble shooting replacing components and ICs but no luck. I've done continuity tests and made sure the voltages were correct. What am I missing?! Any help would be much appreciated. Thank you.


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## Robert (May 16, 2019)

Which EEPROMs are you using?


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## MobiusOne (May 17, 2019)

I'm using an EEPROM from Small Bear Electronics. But I haven't programmed anything into it. I bread-boarded the schematic on the data sheet provided on the Spin Semi site using the same components from SBE and then later added a rotary switch using resistors from a schematic I found on a post from the DIYStompboxes forum. It worked just fine with the 8 internal demo programs and I figured it would work in the same manner on your board. Do the EEPROMs need to be programmed to work on your board?


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## zgrav (May 17, 2019)

you need to ground one of the pins on the fv1 to get the built-in programs to work.  are you getting a dry signal coming through the PCB?  if grounding the pin (sorry - I do not recall which one right now) does not give you the built-in programs, I would suggest putting together a simple audio probe to make sure you are getting an audio signal into the FV-1 on pin 1, and then see if you are getting any audio coming out of the FV-1 on pin 24.


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## Robert (May 17, 2019)

MobiusOne said:


> I'm using an EEPROM from Small Bear Electronics. But I haven't programmed anything into it. I bread-boarded the schematic on the data sheet provided on the Spin Semi site using the same components from SBE and then later added a rotary switch using resistors from a schematic I found on a post from the DIYStompboxes forum. It worked just fine with the 8 internal demo programs and I figured it would work in the same manner on your board. Do the EEPROMs need to be programmed to work on your board?



Yes, the EEPROM contains the effect algorithms.   If you're using a blank EEPROM you won't get any wet signal unless you activate the internal programs.

Ground the point circled in red to run in Internal mode.


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## MobiusOne (May 17, 2019)

Yes, I am getting a dry signal and the volume control works just fine, as well as the mix control since the the dry signal disappears when turned all the way to the right. This makes sense actually. I can find the pin that needs to be grounded and hopefully it works. Eventually I will get a a programmed EEPROM since I saw on your site that I can choose from a list of effects which is really awesome. If I get one, I should be able to just drop it into the socket, correct? Thank you so much for your time. I really appreciate it.


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## MobiusOne (May 17, 2019)

Robert said:


> Yes, the EEPROM contains the effect algorithms.   If you're using a blank EEPROM you won't get any wet signal unless you activate the internal programs.
> 
> Ground the point circled in red to run in Internal mode.
> 
> ...


Thank you so much. I will try this now


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## MobiusOne (May 17, 2019)

It worked! Thanks again guys. I'll be placing an order for the programmed ones soon.


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