Super Hard On not working!

[GibsonGM]

Hi, welcome, and let's see what we can do!   1st - that's not a 'schematic', it's a vero layout.  It shows how the parts sit, but takes more than a glance to see how the electrically connect.   Big difference, to some of us.  We can work with it, tho (the schematic is readily available).

Read this thread, and try to get the info posted here, ok?  http://www.diystompboxes.com/smfforum/index.php?topic=29816.0     

Can't do much on guesses.  Yes, it really does sound like your transistor may be misbiased, but won't know til you give us the required data.  Esp. if you used a BS170 or other device, and also you need to be VERY sure of your pinout - not all devices have the same pinout (sometimes diff. manufacturers have different pinouts).    Go back over EVERY connection and try to spot problems, miswires, and solder bridging....

[stallik]

I'm only looking at this on my phone and it's difficult for me to see. (excuses,  excuses) but will someone with better eyes than me check the orientation of that diode.  Ta

[jonnygreentrees]

the diode is black stripe facing south

[peterg]

Welcome to the forum. Check for solder bridges as others have pointed out. Looks like a couple between the lowest full row and the second row at the 4th and 7th holes from the left. You may want to desolder and try again with less solder.

[Jdansti]

Try running your iron's tip between the tracks to clean things up. If you have a wedge type tip, turn it on its side when doing this.

[GibsonGM]

You can also use a pick...anything like a dentist's pick, they used to include them in Radio Shack's "Soldering Kit" *rolling eyes* - you heat the area that is bridged, and use the wedge of the pick to 'carve' a path between them to break contact...

[acehobojoe]

Tell me the voltage on the g d and s of that transistor. I would suggest however that you start over fresh and use way less solder and make it look as neat as possible. There is also a setting on most multimeters to measure if there is a connection being made, use that to check your cuts and various regions of the board to make sure nothing is shorting together.

[stallik]

the diode is black stripe facing south

That makes the diode the wrong way round then?

[peterg]

The diode is the right way around as per the schematic. The vero layout shows the band in white.

[stallik]

Oops. Having a senior moment. As you were guys

[MrStab]

i know it's kinda lazy to just pitch this, but just for the fornicate of it, could the MOSFET just need replacing? i don't know much about the SHO beyond the "Crackle Ok!" thing and the fact that more recent models have the diode to prevent static damage, but it's possible the MOSFET was damaged by handling. Worth trying a replacement, at least, to rule it out. My bad if you've already tried it, Jonny, or if that wouldn't add up with the symptoms. Mike's already suggested a biasing issue with it, though.

...i've just realised something: there was a guy in my class at school called Jonny Greenlee. are you him? lol

[acehobojoe]

I have used the bs170 in about 10-15 boost pedals I sold, and there were only 2 duds. The duds seemed to be crackling excessively and not balancing power well. Initially I did kill one or two, but I solder them direct into board now and there are no issues.

It is possible to mess one up with static, but like OP, my transistor problems were far more likely based on improper soldering, bridges, and excess flux.

If I am remembering correctly, you should have around 5v on the drain, and 3v or so on the gate and maybe around 1v on the source. That was with my build, but I think you should have nearly the same voltage.

Solder bridges are incredibly common for beginners. Especially on vero. I am thinking that is the problem. It's easier to diagnose neat as well.

I'm not an expert, but I don't think it's the mosfet, though it would be worth swapping after he is sure of every connection.

[acehobojoe]

https://learn.adafruit.com/adafruit-guide-excellent-soldering/common-problems

[MrStab]

i've killed my fair share of 2N7000s by static, so i thought it was worth a mention. possibly because i was a bit less-experienced when making those Millennium circuits, but more likely because i'm a complete moron. i haven't actually had any failures with signal-path MOSFETs, now i think about it, so i have no experience of how that'd actually sound.

[GibsonGM]

See what he comes up with for voltages, I think.   I've altered a few MOSFET designs (by using the wrong MOSFET.....), had to monkey with them a fair amount to make them work, but don't know if he is using a 170 or other FET yet.   What has happened to me a lot is to need to change the drain R to some very far off value to get my bias correct.  Mainly, I've set the D to about 1/2 supply, and off it goes.   As  I understand it, there aren't too many designs you can just plug different MOSFETs into and have them work right off...

But - yeah, a soldering issue may well be the culprit here.  Most easy thing to do, making solder bridges    

[acehobojoe]

Yea, it would be cool to get a close up pic of the mosfet. We could look it up and see if it's fairchild, futurelec or whatever.

[LightSoundGeometry]

grounding. sometimes if things are not grounded a certain way they will not work.

for example, in my guitar cavity I can ground lug 1 back on itself but in a pedal build this will not work..or I have yet to get it to work. I had a tillman preamp that would not fire up until I grounded to the jack instead of the pot

[MovingInSloMo]

I've used the theory "flow like water" and use lots of flux. Only enough solder to maintain a strong electrically conductive joint. it takes practice.

[Les Paul Lover]

Your soldering isn't great, it looks like there could be a lot of bridges there.

I'm not sure how big is your solder wire, but I was getting huge blobs too until I started using thinner wire. The fatter write is better for connections like pots, footswitches, jacks.

I would start that one anew, but you'll probably fry your bs170 trying to unsolder it. You'll most likely will need a new one.

Also, your pot connection isn't right. If you download the schematic from the page I link to (that's the clone I built), you'll see the pot is in the circuit. Not just from the circuit and to ground, but is there to decide how much of the signal should be amplified by the transistor.


http://shop.pedalparts.co.uk/Boner_Boost/p847124_6343638.aspx

[acehobojoe]

That will sure help your ED.