# VHS, no sound, FV-1 issue? (SOLVED)



## irvmuller (Aug 29, 2020)

So, I built a 2 in 1 pedal. It’s a VHS going into a Phase II. I’m getting clean signal though the pedal. The Phase II works perfectly. The VHS, when I engage it it gives me a hiss sound and no bass signal. I notice when I switch on the Chorus or Reverb there is a loud pop. No pop when I switch on the Boost. There don’t seem to be any power issues. All the LEDs light up perfectly. I accidentally ordered Film Caps for 1u instead of Electrolytics and just used film. The Film Caps were too big to be on top and so I connected them from underneath. 
Any input is helpful.


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## irvmuller (Aug 29, 2020)

Here is a pic of the other side...


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## dlazzarini (Aug 30, 2020)

irvmuller said:


> Here is a pic of the other side...
> View attachment 6074


I think the build docs call for your 1uF caps to be polarized electrolytics.  I know in certain situations non polarized caps can be used in place of electros but I’m not that schooled yet so this may or may not have anything to do with your hiss


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## whiiiskey (Aug 30, 2020)

I think you've discovered the main reason electrolytics are used. they generally take up less space for their capacitance value. You might want to use an audio probe to track down at what point the noise enters the signal path.

Also according to this there are technical reasons for using them as parts of power supplies, some of the explanation is beyond my paygrade ?https://www.arrow.com/en/research-a...itors-simple-in-concept-not-in-implementation


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## Boba7 (Aug 30, 2020)

All the 1uf caps are in the signal path, so no worries with them being film instead of electrolytics. Maybe one leg is shorting against another pad? 
When it's out of the enclosure, does it still not work?


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## irvmuller (Aug 30, 2020)

I don't think the 1uf caps are the issue in and of themselves because they are only in the signal path. I did recheck them and the legs aren't touching anything they shouldn't. *HOWEVER, all this talk about the 1uf caps made me remember I had to pull one of the caps a little hard in order to get it to fit *and I was slightly concerned it could have jacked it up. Specifically, it was the one in the back that's touching the switch. I had to really stretch it to make it fit. So, today I'm getting electrolytic caps delivered and I will change that one out first and see if that fixes things. I'll get back with you guys if it does.

Thanks for all the input.


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## irvmuller (Aug 30, 2020)

Update...
Changed the 1uf cap but still not working. Finally made myself a audio probe. *I’m finding the signal drops at the 3rd spot in the FV-1*. I don’t know if the issue is with the FV-1 that pedalpcb installed or with the 10u that it grounds to there. I’m changing out the 10u electrolytic and seeing if that helps.

If anyone knows how the FV-1 works please let me know.


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## Boba7 (Aug 30, 2020)

irvmuller said:


> Update...
> Changed the 1uf cap but still not working. Finally made myself a audio probe. *I’m finding the signal drops at the 3rd spot in the FV-1*. I don’t know if the issue is with the FV-1 that pedalpcb installed or with the 10u that it grounds to there. I’m changing out the 10u electrolytic and seeing if that helps.
> 
> If anyone knows how the FV-1 works please let me know.



I dont think there is any signal going to pin3, so dont bother changing the cap. 
Is there any signal coming in at pin1&2 and coming out at pin 28?


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## Boba7 (Aug 30, 2020)

Also, you should probably post voltages for all ICs in your build.


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## irvmuller (Aug 30, 2020)

Pins 1 and 2 do have signal. Checking voltages next. Never had to do that so I’m gonna look it up. I do have a good multimeter.


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## Boba7 (Aug 30, 2020)

No signal at pin 28?


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## irvmuller (Aug 30, 2020)

Boba7 said:


> No signal at pin 28?



no signal at pin 28...


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## irvmuller (Aug 30, 2020)

Boba7 said:


> Also, you should probably post voltages for all ICs in your build.



FV-1
1. 1.65
2. 1.65
3. 1.65
4. 0
5. 1.2
6. 3.3
7. 0
8. 3.3
9. 1.4
10. 1.16
11. 0
12. 0
13. 3.3
14. 3.3
15. 3.3
16. 0
17. 0
18. 0
19. 0
20. 1.95
21. 2.7
22. 0
23. 3.3
24. 0
25. 0
26. 3.28
27. 0.87
28. 1.04

IC2
0
0
0
0
3.3
3.3
0
3.3

IC1
4.54
4.54
4.5
0
4.5
4.55
4.55
9.09


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## irvmuller (Aug 30, 2020)

irvmuller said:


> FV-1
> 1. 1.65
> 2. 1.65
> 3. 1.65
> ...



Also the L78L33

Input 9
Ground 0
Output 3.3


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## irvmuller (Aug 30, 2020)

So, I noticed this build up of white crusty stuff along the VH-1. I used some contact cleaner to clean it off. An hour later and this was on there... normal? not normal?


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## Robert (Aug 30, 2020)

irvmuller said:


> So, I noticed this build up of white crusty stuff along the VH-1. I used some contact cleaner to clean it off. An hour later and this was on there... normal? not normal?



Looks like the residue from "No-Clean" flux....      It looks awful but I haven't seen it cause any issues so far.

I was just complaining about this stuff in another thread the other day.


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## Boba7 (Aug 31, 2020)

irvmuller said:


> FV-1
> 1. 1.65
> 2. 1.65
> 3. 1.65
> ...



I'm no FV1 expert, I haven't used that chip much, so you may need some help from someone else

Your voltages look fine to me, except for pin 13 of the FV1, that should be about 3.3v I believe. Other than that it all seems fine. Did you check all your resistor values, and your soldering? 

Also, definitely not your issue here, but careful with those leds by the footswitches, their legs could short against the enclosure quite easily.

Good luck !


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## irvmuller (Aug 31, 2020)

Boba7 said:


> I'm no FV1 expert, I haven't used that chip much, so you may need some help from someone else
> 
> Your voltages look fine to me, except for pin 13 of the FV1, that should be about 3.3v I believe. Other than that it all seems fine. Did you check all your resistor values, and your soldering?
> 
> ...



pin 13 was 3.3. I put 0 down on accident. I edited the original comment.

I noticed others had 3.3 on pin 16 as well. I rechecked it but turned on the switches this time. It read at 3.3 as well.


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## Boba7 (Aug 31, 2020)

I honestly don't know.

Check continuity between the FV1 pins and the surrounding resistors and caps. Check again all the parts values.
Hopefully someone smarter than me will come up with an idea!


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## Boba7 (Aug 31, 2020)

Did you try another opamp? It would be a good idea to socket the ICs and transistors/votlage regulators
And check if there's any bridges on the switch board.


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## irvmuller (Aug 29, 2020)

So, I built a 2 in 1 pedal. It’s a VHS going into a Phase II. I’m getting clean signal though the pedal. The Phase II works perfectly. The VHS, when I engage it it gives me a hiss sound and no bass signal. I notice when I switch on the Chorus or Reverb there is a loud pop. No pop when I switch on the Boost. There don’t seem to be any power issues. All the LEDs light up perfectly. I accidentally ordered Film Caps for 1u instead of Electrolytics and just used film. The Film Caps were too big to be on top and so I connected them from underneath. 
Any input is helpful.


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## irvmuller (Aug 31, 2020)

Went through ALL my pieces last night: resistors and caps just to make sure EVERYTHING was the right value. I also added extra solder to a few pieces that I thought might need it. No luck.

I'm starting to lose hope on this one and am wondering if I need to start over or just move on.  I've built over 15 pieces and this is by far the most trouble I've had and might be my first failure to work. I just can't figure this one out. 

I did not socket parts this time and I usually do. That's on me.

Gonna try to check continuity later today. Not sure how that works with the FV-1.


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## Boba7 (Aug 31, 2020)

irvmuller said:


> Gonna try to check continuity later today. Not sure how that works with the FV-1.



Just put one probe on an FV1 pin, and the other to a resistor/cap that's supposed to connect to it. See if there's continuity everywhere.

Maybe @p_wats could help, he seems to have doing quite a bit of troubleshooting around FV1 builds these days!


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## p_wats (Aug 31, 2020)

Boba7 said:


> Just put one probe on an FV1 pin, and the other to a resistor/cap that's supposed to connect to it. See if there's continuity everywhere.
> 
> Maybe @p_wats could help, he seems to have doing quite a bit of troubleshooting around FV1 builds these days!



Ha. That I have, though not by choice. 

Nothing special about continuity checking with the FV-1, just follow the schematic and check that the right pins show continuity to the right components (ie, pin 13 should connect to one side of R5).

I recently ran into a bad noise issue that turned out to have been caused by a tiny lifted trace near lug 2 of the mix pot. All the jostling to get the board in/out of the enclosure put pressure on the board-mounted pots and cut off VREF from where it needed to go next.

To that end, if I were you, I would follow the schematic and make sure continuity is right for each component connection. The good news is that if I can fix my ailing build then you definitely can too!


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## irvmuller (Aug 31, 2020)

Ok. Did my homework. Everything seems to have continuity. Frustrating but nice to have a new skill. I’ll keep digging.


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## zgrav (Aug 31, 2020)

Here are some other things you can check:

Make sure the value for C11 is correct, since that pot connects the audio path to ground.  

You can also check to see if your audio probe picks up any signal on pin 27 of the FV1 (it is an audio output, but not actually connected to anything in this case).  If you had sound on pin 27, you might be getting output to pin 28 that is being shunted to ground.  Check to see if you have any unintended ground connections to the audio path between the FV-1 pin 28 and the connections all the way to the output jack.  The only parts that are supposed to connect to ground are C11 and R4.

If you are not getting any audio signal on pins 27 or 28, you could also try using a jumper wire to  connect FV-1 pin 1 to pin 28 to see if you get a clean signal going through to output.  if so narrows your troubleshooting down to the FV-1.

At that point, if you have a spare crystal, go ahead and replace the one on the board to see if that brings your FV-1 to life.


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## irvmuller (Aug 31, 2020)

zgrav said:


> Here are some other things you can check:
> 
> Make sure the value for C11 is correct, since that pot connects the audio path to ground.
> 
> ...



So, C11 is correct.

No sound out of pin 27.

When I jump pins 1 and 28, no signal passes... which is confusing to me.

I'm going to go ahead and change out the crystal. I happened to order an extra one and so am lucky to have it on hand.

Thanks for all the suggestions.


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## irvmuller (Sep 1, 2020)

Big news today.

I tried jumping pins 1 and 28 before but no signal passed. *HOWEVER, I jumped pin 1 to C8, the first cap after the FV-1, and signal passes!*

So, the issue must be with the FV-1or the way it was soldered on. At least I think. I already changed the crystal so it's not that.

Moving from here, I want to hear what possible solutions you guys might have. Please holler back guys.

I'm hoping to be able to fix this one. I did finish checking continuity and couldn't find any issues with that. I've never had to solder a chip that small before so if I have to do that it'll be something new for me.


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## irvmuller (Sep 1, 2020)

Bigger news! I grounded pin 13 and the signal passed through perfectly. *This means the issue is with the eeprom!*

Next steps anyone?


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## p_wats (Sep 1, 2020)

irvmuller said:


> Bigger news! I grounded pin 13 and the signal passed through perfectly. *This means the issue is with the eeprom!*
> 
> Next steps anyone?



Good progress! When you ground pin 13 does it produce an effect (the internal FV-1 programs should be on at that point---the first one is a reverb with modulation, if I recall)?


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## irvmuller (Sep 1, 2020)

p_wats said:


> Good progress! When you ground pin 13 does it produce an effect (the internal FV-1 programs should be on at that point---the first one is a reverb with modulation, if I recall)?



Yes, it does produce the effect!


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## zgrav (Sep 1, 2020)

you have already verified your connections between the eeprom and the FV-1, so there is a chance you have a blank (or defective) eeprom.  (just to be sure -- did you verify connectivity *from the pins on the eeprom* to the FV-1? if not -- give that a quick check to make sure it is not just a bad socket)

assuming your eeprom is in contact with the FV-1, you should get another eeprom and give it a shot.


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## irvmuller (Sep 1, 2020)

zgrav said:


> you have already verified your connections between the eeprom and the FV-1, so there is a chance you have a blank (or defective) eeprom.  (just to be sure -- did you verify connectivity *from the pins on the eeprom* to the FV-1? if not -- give that a quick check to make sure it is not just a bad socket)
> 
> assuming your eeprom is in contact with the FV-1, you should get another eeprom and give it a shot.



The eeprom in this case is programmed by pedalpcb into the FV-1. That's why when I ground pin 13 signal finally passes. Something must have gone wrong in programming it. 

If you're talking about IC2(24LC32A), that kicks in at pin 14 and is allowing signal to pass.


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## zgrav (Sep 1, 2020)

the eeprom holds the programs for the FV-1 and are loaded in every time the pedal is powered on or when the program knob is changed.  that is why you can order different eeproms to change the programs that run on the FV-1.  the programs that are in the internal memory are part of the FV-1 chip.

you can ask to get a replacement eeprom mailed to you to see if that solves the problem.  someone else also had a bad or blank eeprom for a build a couple of months ago, so that seems to be the case here as well.


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## Robert (Sep 1, 2020)

The VHS algorithm is on the 24LC32A, not loaded directly onto the FV-1 IC.

Grounding pin 13 disables the external 24LC32A EEPROM and runs the internal programs of the FV-1 IC. 

Check for 3.3V on Pin 8 of IC2 and verify continuity between IC2 Pin 5 / IC3 Pin 15, and IC2 Pin 6 / IC3 Pin 14.
Also verify that Pins 1 - 4 of IC2 measure 0V (continuity to ground).

If all of this checks okay it sounds like I need to ship you a replacement EEPROM.


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## Nostradoomus (Sep 1, 2020)

This happened to my Deflector...eeprom blanked itself out, flashed it, blanked out again...waiting for some new eeprom chips to try again. Very odd.


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## irvmuller (Sep 1, 2020)

Robert said:


> The VHS algorithm is on the 24LC32A, not loaded directly onto the FV-1 IC.
> 
> Grounding pin 13 disables the external 24LC32A EEPROM and runs the internal programs of the FV-1 IC.
> 
> ...



I just checked all of that and it all checked out...


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## Robert (Sep 1, 2020)

irvmuller said:


> I just checked all of that and it all checked out...



Is your shipping address still the same as your last order?


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## irvmuller (Sep 1, 2020)

Robert said:


> Is your shipping address still the same as your last order?



Yes it is. And thank you for treating customers right. You guys are first on my list when buying!


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## Boba7 (Sep 2, 2020)

Great, it seems you’re gonna make it work! And you got to learn a few debugging tricks!


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## irvmuller (Sep 2, 2020)

Boba7 said:


> Great, it seems you’re gonna make it work! And you got to learn a few debugging tricks!


I definitely learned a lot. Thanks for all the help.


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## irvmuller (Aug 29, 2020)

So, I built a 2 in 1 pedal. It’s a VHS going into a Phase II. I’m getting clean signal though the pedal. The Phase II works perfectly. The VHS, when I engage it it gives me a hiss sound and no bass signal. I notice when I switch on the Chorus or Reverb there is a loud pop. No pop when I switch on the Boost. There don’t seem to be any power issues. All the LEDs light up perfectly. I accidentally ordered Film Caps for 1u instead of Electrolytics and just used film. The Film Caps were too big to be on top and so I connected them from underneath. 
Any input is helpful.


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## irvmuller (Sep 10, 2020)

Hey Everyone! I wanted to update everyone with the good news. I got the replacement EEPROM and it works! While I don’t think this was due to anything wrong I did it was a great experience that helped me learn a lot of new skills but also helped me learn some more things about how pedals work!

Thanks to everyone who gave input and to pedalpcb for making things right and sending a new EEPROM.


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## p_wats (Sep 10, 2020)

Nice! Glad you got it sorted


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