SOLVED Spatialist reverb no reverb effect

[cai]

Hey I'm looking for some help and guidance troubleshooting a spatialist reverb. I have guitaer signal but no reverb. The volume pot works as expected, however due to there being no reverb signal the mix pot effectivly just turns the volume down. I have an audio signal reaching pin 1 of the FV-1 chip, tested by measuring ac voltage, but nothing leaving the chip. I have already checked the fv-1 for grounds, it is getting the correct 3.3v and all pins have continuity to other components where they should.

I'm really lost, any help on how to continue troubleshooting would give me hope lol.
Thanks

 

[jwin615]

Assuming you have the eeprom in...
Reverb out should be on 28, top right.
If it's silent, you can try lifting the pin 12 side of C7. Then ground that pad. It *should* work on the internal programs then. That will help separate if it is eeprom or fv-1 related.
Before you do that, check all your diodes orientation and maybe post some photos. The diodes and rotary form a binary selector across the S0 S1 and S2 pins. Though. I would suspect even if something were awry there, you would be stuck on one program. You should have various combinations of 0V/3.3V on those pins, depending on the switch setting.

 

[cai]

Here are some pics, havent got it into an enclosure yet. I always test before adding a switch etc. Let me know if you need more photos.

I tested the voltages on pin S0, S1 and S2, here are the results?

Position 1

Pin 16: 0v
Pin 17: 0v
Pin 18: 0v

Position 2

Pin 16: 3.31v
Pin 17: 0v
Pin 18: 0v

Position 3

Pin 16: 0.01v
Pin 17: 3.32v
Pin 18: 0.02v

Position 4

Pin 16: 2.87v
Pin 17: 0.02v
Pin 18: 0.02v

Position 5

Pin 16: 0v
Pin 17: 0.02v
Pin 18: 3.32v

Position 6

Pin 16: 2.87v
Pin 17: 0.04v
Pin 18: 2.87v

Position 7

Pin 16: 0.01v
Pin 17: 2.87v
Pin 18: 2.87v

Position 8

Pin 16: 2.87v
Pin 17: 2.87v
Pin 18: 2.87v

 

[jwin615]

Can you probe for audio on pin 28 of the fv 1.
How about pin 10 and 8 on the 074?
Also, are those all mlcc caps? Not tants?

 

[jwin615]

From the photo, that pin 28 looks a little iffy. May look fine IRL though.
Curious if there's audio there. If there is, reflow it.

 

[cai]

I don't have an audio probe, I just test by measuring AC voltage on my multimeter, strumming my guitar and watching for fluctuations. The 1u capacitors are all mlcc caps, as for the rest the build guide doesnt specify. I just used a combination of the poly box type and ceramics.

There appears to be no audio signal at pin 28, the AC voltage reading doesnt fluxuate

 

[cai]

Pins 10 and 8 on the 074 also have no audio signal (no AC voltage fluctuations when guitar is strummed)

 

[jwin615]

K. Lift/desolder the pin 12 side of C7. You should be able to see a trace. Then check for audio.
That *should* force the fv-1 to use it's internal programs. If it works from there, it's an issue with the eeprom. If it doesn't, need to look closer at the fv-1 and surrounding components.

 

[cai]

Okay will do. Thanks!

 

[jwin615]

Let me double check the datasheet before you desolder.

 

[jwin615]

NOPE! Lift R5/pin 13
Either side. Sorry.
Didn't follow the lines on my phone right.

 

[jwin615]

NOPE! Lift R5/pin 13
Either side. Sorry.
Didn't follow the lines on my phone right.

Okay. I'm tired. I think you should short the pin 13 side of R5 to ground. No soldering required.
Lemme see if I can find that thread...

 

[jwin615]

Connect the left end of R5 to ground and see if you get a wet signal. It won't be the Spatialist effects, but it will determine if the EEPROM is the problem.

View attachment 76244




It's rare, but if the FV-1 IC ends up being the problem you'll get a replacement.

From this thread
Sorry, trying to get the kiddos to bed and look at datasheets and ...

 

[cai]

Okay thank you very much. When you say connect it to ground without soldering how would I do that? just wrap a wire round the leg? Sorry I'm quite new to this level of electronics. This is only the 5th pedal I've built.

I appreciate you taking your time and helping me

 

[jwin615]

Okay thank you very much. When you say connect it to ground without soldering how would I do that? just wrap a wire round the leg? Sorry I'm quite new to this level of electronics. This is only the 5th pedal I've built.

I appreciate you taking your time and helping me

Any means necessary.
Alligator clips or the like would be good.

 

[jwin615]

Read over the linked thread
Good tips in there as well.
Many of the PPCB fv-1 projects are built on the same board.
Another tip, if you aren't quick at reading resistor values, open up a build report with high res photos and use it to compare to yours

 

[cai]

I reflowed the FV-1 chip and the program selection circuit. I also swapped out D2 and D3 as when tested they were faulty. I'm unsure if it was the diodes that caused the lack of signal or whether there were bad connections and the reflow solved it. Either way its alive and it sounds beautiful.

Thank you @jwin615 for the help, couldn't have done it without you.