# Hydra delay - not delaying



## Brambasstik (May 14, 2020)

Hi everybody !
This is my first build... I checked a lot of models and by the time I ordered my kit on Musikding, I'd forgotten that this one had a FV-1...
So I figured I'd still go for it... And as could be expected, I blew it ! ?
I found a first mistake : LED was not the right way (serves me for wanting to finish before bedtime... I kinda figured the long leg went in the square hole, like the capacitors, and didn't double check ?)
That's fixed, but I still don't get any delay. It powers up, I get a red LED, and volume and mix pots seem to work, but I only get the clean signal coming through. If I turn the mix all the way to full wet, no signal.
I checked all my solderings, and it's not the cleanest work of course, but I don't see a bad joint. I had a bit of trouble with the FV-1, I'd never soldered a sSMD before, I'm afraid I might have fried that ? How can I check ?

Anyone have an idea about where to start looking and what to look for ?
A couple pics if you can see anything relevant there :







Thanks a lot for your comments & help !


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## Brambasstik (May 14, 2020)

Something I noticed is the swell pot is labeled 100k on the pcb, but c50k on the build docs. I got a 50k in the kit, figured it was the right one and put that in.


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## Robert (May 14, 2020)

The C50K taper had a better response, so that is correct. (Either would work though)

The FV-1 is pretty tolerant to heat, so you're probably good there, but it might not hurt to reflow the solder on the pins.

The next step would be to connect the Right side of R5 to ground using a jumper wire.  This will force the FV-1 to run the internal programs instead of the Hydra algorithm.     It won't sound like the Hydra, but if you hear effects you'll know the FV-1 IC is working and can suspect the EEPROM as the problem.


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## Brambasstik (May 14, 2020)

Hi, thanks a lot for your quick input !
So I soldered the right side of R5 (right as seen from the component side of the PCB) to the ground pin of the switch... same symptoms. I reflowed the contacts using flux this afternoon, but I'll double-check !


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## zgrav (May 14, 2020)

build an audio probe.  you can do a google search to see how to put that together.  it is easy.

after you have the audio probe put together, test it to make sure you hear sound when running audio into the pedal and you put the probe against the audio in wire at the board.  you want to use the probe to check pin 1 on the FV-1 to see if your audio signal is reaching the chip.  if you hear sound there, check pin 28 of the FV-1 to see if sound is coming out of the chip.

if sound is not reaching the chip, use the schematic to check the parts in the audio path to see where the sound stops and fix it. 

if sound is reaching and leaving the FV-1, use the probe to find out where it stops before it reaches the mix pot, and fix it.


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## Brambasstik (May 15, 2020)

Thanks Zgrav ! Using my brand new audioprobe, I found that signal was coming in R3, but nothing was coming out. Measured it to 1meg instead of 1k. So I checked all the resistors in case I had inverted something, and in fact both 1k resistors on the circuit are wrong... little mistake at Musikding I guess. At least I know some resistor codes by heart now !


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## zgrav (May 15, 2020)

I hope that everything works after you change the resistors.  I know that a few builders, including me, will use a meter to test each resistor to make sure it is correct before soldering it in place.  Only takes a few seconds and saves lots of time in the long run.


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## Brambasstik (May 17, 2020)

It lives ! The resistors were the issue. I'll definitely take your advice and check and measure every resistor from now on.
I tested it out of the box, a lot of noise but I expect boxing it will ground and shield it properly.
I have to think about artwork now 

Another topic : I managed to get 70% isopropanol for pcb cleaning (Hofer Chemie, it's a spray). Will I damage anything if I use it on the board now ?

Thanks a lot for your help !


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## zgrav (May 17, 2020)

it should be OK to use the 70% IPA, but you want to give the board plenty of time to dry before you power it up since you will have 30% water in that mix.   use a toothbrush to clean the board.  I would probably start by just applying the IPA to the toothbrush to clean the PCB.


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## Brambasstik (May 17, 2020)

OK thanks,

I'm following a tuto for pumpernickel compressor, he says not to use pcb cleaner when the pots are installed because it could damage them ? I'm curious as to what it would do to a pot that it would not do to other components in your opinion ?


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## zgrav (May 17, 2020)

cleaner can dislodge small pieces of solder that could end up inside the pots and mess them up.


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## Robert (May 17, 2020)

Some pots have a silicon grease inside to make the rotation feel smooth.     

If you clean them too good it'll make the pot feel loose and floppy.


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