ARACHNID DIED AFTER I TOUCHED SOMETHING...

[RobertJay]

Oh hello, Schematic attached.
I built it, it worked. But I lost track of what the 8 programed effects were for this one. So I was going point to point from the rotary switch source using a wire. Why not use a switch? I actually just want this for one or 2 effects using a toggle switch. And the wire touched the Builder chip on the left side. Legs 1-4. One of them got touched and the build is dead. I replaced the builder chip and still dead. So I'm looking, what else may have been affected. I see 3.3v at the rotary source? Legs 1-4 on the chip all go to ground. What could've happened? Thanks

 

[PJS]

Not sure what you mean by the "builder" chip. Do you mean the FV-1, the TL074 or the EEPROM chip?

 

[RobertJay]

Yes, the eeprom builder chip. Or module 8. But yeah that's the eeprom.

 

[PJS]

1. You replaced the chip. Where did you get the replacement?
2. Measure voltages. Look for 0v on pins 1 to 4 and 7. Look for 3.3v on pin 8. From memory the data lines will also measure about 3.3v on a multimeter (pins 5 and 6).
3. - Have you got an EEPROm programmer? If so you can read back the data on the EEPROM and see if there is anything actually on it.
4. If you lift the end of R5 that is connected to 3.3V (not the end connected to the FV-1) and connect it to ground instead then you will be using the internal programs instead of the EEPROM ones - this will give you a chance to test whether the problem is really with the EEPROM or whether the problem is elsewhere.

 

[RobertJay]

Everything I use is from Pedal PCB. It worked until the jumper from the 8 pt rotary switch touched one of legs 1-4 of the eeprom chip. I replaced the Eeprom with another I had on hand and still the same. Best I can do for now is to replace chips one at a time.

 

[p_wats]

Yeah, as @PJS said, I'd try grounding pin 13 of the FV-1 to see if the internal programs work. They don't require an EEPROM at all, so if you get an effected signal with pin 13 grounded you can at least rule out most of the board.

Does your mix pot work---do you get any dry signal if you roll it back?

Do you have an audio probe to follow along with (they are easy to build)?

 

[RobertJay]

I will remove the resistors in place and put the mix pot in to do just that. Of course audio probe! How dare you? Haha And... What's this about internal programs? Like there are already programed effects in the fv-1? And then the Eeprom works off of those? That's new to me, if so. Thanks!

 

[p_wats]

I will remove the resistors in place and put the mix pot in to do just that. Of course audio probe! How dare you? Haha And... What's this about internal programs? Like there are already programed effects in the fv-1? And then the Eeprom works off of those? That's new to me, if so. Thanks!

I don't think you need to do anything to the mix pot. Just test it---if you turn it all the way down do you get your dry signal at all? That would tell you if that section of the circuit is working.

The FV-1 has internal programs (a few reverbs, etc.) that don't require an EEPROM to access. Just ground pin 13 of the FV-1 chip and they should take over if all is working.

 

[Cybercow]

I will remove the resistors in place and put the mix pot in to do just that. Of course audio probe! How dare you? Haha And... What's this about internal programs? Like there are already programed effects in the fv-1? And then the Eeprom works off of those? That's new to me, if so. Thanks!

The FV-1 has a set of internal programs that can be accessed WITHOUT an EEPROM being in place. Pin 13 of the FV-1 needs to be grounded to access them. The 10K resistor (R5) will prevent any damage to the FV-1/EEPROM power supply.

Here are the list of internal programs built-in to the FV-1 . . .



Now, all that being said, you will still want to dbl-check the power supply distribution system for Vcc, VRef and the 3.3V - If those are all still in tact, then you may have blown the FV-1 chip when you said you touched one of the 8-way rotary pins to ground (pins 1-4 on the EEPROM are ground).

Let us know what you find.

 

[RobertJay]

The FV-1 has a set of internal programs that can be accessed WITHOUT an EEPROM being in place. Pin 13 of the FV-1 needs to be grounded to access them. The 10K resistor (R5) will prevent any damage to the FV-1/EEPROM power supply.

Here are the list of internal programs built-in to the FV-1 . . .

View attachment 55924

Now, all that being said, you will still want to dbl-check the power supply distribution system for Vcc, VRef and the 3.3V - If those are all still in tact, then you may have blown the FV-1 chip when you said you touched one of the 8-way rotary pins to ground (pins 1-4 on the EEPROM are ground).

Let us know what you find.

Wow, thanks! I do feel the notes and descriptions of these circuits are limited on the site. This issue aside... I could be saving money on each build without the EEPROM chips? I literally use this pcb for Chrous, Flanger, Pitch shifter, all of which are apparently included in the FV-1 Spin Chip? Hilarious. I've been ordering Module 8 and Builder chips for them. This is a WIN regardless of troubleshooting the defective one, which is still on the troubleshoot list. Thanks!

 

[Cybercow]

Wow, thanks! I do feel the notes and descriptions of these circuits are limited on the site. This issue aside... I could be saving money on each build without the EEPROM chips? I literally use this pcb for Chrous, Flanger, Pitch shifter, all of which are apparently included in the FV-1 Spin Chip? Hilarious. I've been ordering Module 8 and Builder chips for them. This is a WIN regardless of troubleshooting the defective one, which is still on the troubleshoot list. Thanks!

Pretty much. But note that the stock FX patches are just that; 'stock'. Robert's patches may be more robust/flexible. But, TBH, I've never spent the time to compare them. So you may want to A/B (compare) some of the patches and see if they meet your expectations.

 

[RobertJay]

Oh I am! I'm about to buy a pythagorum w FV1, and an arachnid or 2. Going to grab a few module 8 and builder EEPROMS for comparisons and I'll figure the cheapest way to get the few FX I need. Thanks. And... STOCK. I get it. The effect is there, but the EEPROM might be written to change what's there. I get it.

 

[p_wats]

Wow, thanks! I do feel the notes and descriptions of these circuits are limited on the site. This issue aside... I could be saving money on each build without the EEPROM chips? I literally use this pcb for Chrous, Flanger, Pitch shifter, all of which are apparently included in the FV-1 Spin Chip? Hilarious. I've been ordering Module 8 and Builder chips for them. This is a WIN regardless of troubleshooting the defective one, which is still on the troubleshoot list. Thanks!

The stock patches are OK, but nothing special. I've built several FV-1 builds and have included a toggle to revert to stock patches, but never use it. Depends on what you're after in terms of the actual effect though, so whatever works for you!

 

[PJS]

There are also plenty of patches that people have written available on the net. One person has even collated most of them together on Github. You can get a cheap EEPROM burner (or use an arduino as an EEPROM burner I believe) and try out everything out there. I have the original Modul8 EEPROM, and a couple of others that I experiment with.

 

[PJS]

Next challenge - get the FV-1 datasheets and the programming guides and teach yourself FV-1 assembly