Neutrino fault finding

[andywragg]

GOt my Neutrino assembled but I get no tone when its switched on. Bypass is good  and when switched on LED comes on but nothing else.

I had to gerry rig the C3 and C5 as by mistake I bought a 10mm pitch package as opposed to 5mm.

Any suggestions?

[Boom]

Nothing at all when on ?

I would start by checking the stompbox wiring, making sure the effect in and out leads aren't shorting out anywhere. Be aware that they can also short out to the lid of the enclosure if you have the switch screwed down too low.

If that's not it, I usually trace the signal path on the board under a magnifiyng glass to check for solder bridges  shorting it to ground. It helps to color the trace on a printout of the pdf (board and schematic). This makes tracing it easier and creates an understanding of how the circuit works. (for me anyway)

Is th IC sitting firmly and correctly in it's socket and getting power ?

Good luck

[andywragg]

I've had a good look at the board. The Tone pot is a bit crackly (I'll get some contact cleaner on it) and adjusting the gain pot to max produces a gentle hiss. I think the problem may be C1. The package I bought has a pitch which is narrower than the holes on the board so I had to bend the legs out, and they are quite short.

The other thing could be the chip as I soldered it directly to the board. But i'm guessing I wouldnt get the hiss if the amp was dead.

[lincolnic]

This is a long shot, but on the Sabertooth I built for a friend of mine, I had a similar problem - turned out one of the pot legs had rotated when I screwed it in and was touching the LED bezel and shorting out. A little heat shrink solved that problem.

No idea if this helps you at all, but sometimes it's the little things that make you go "derp".

[andywragg]

OK done a bit of DVM measuring.

At the 9V input I get 9V on a dry cell, and just over 12v on my multi-effects PSU.

At pin 8 on the IC i get either 2v (dry) or 3v (PSU) which I think is the problem (isnt it?)

I've checked across R8 (330 ohm) and this is where the voltage drop occurs. on the 9v input side of the resistor its as expected. On the IC Pin 8 side its as above. The measurements are taken on the resistor so its not a bad joint - or so i think.

HEELLPPP

[oldhousescott]

Check for the correct orientation of D5 and C7. The "stripe" on the diode should be toward the center of the board, and the " arrow stripe" on the capacitor should face toward the edge of the board.

[andywragg]

Yep - They are OK

[andywragg]

OK BIt of progress.

I've been over most of the joints with the iron just to make sure and I've also replaced all the electrolytic caps.

I can now hear the guitar tone IF I turn my amp way up. The volume pot is working as I can adjust the level. The drive and tone pots dont seem to make much difference yet. So now I have a very good attenuator.

I'm going to wait until the correct sized caps come and then remove the IC and fit a socket to allow me to swap between the 4558 and the LM1458.

I've also part assembled the Black version, but need some bits from the order I have on the way.

[Mr. G.]

I suggest double checking the value of R8 to make sure that it really is 330r.  I believe you'll have to desolder one leg to get an accurate reading.

[Mr. G.]

Also, what is the voltage reading between R9 & R10?

[andywragg]

Also, what is the voltage reading between R9 & R10?

1.16v on the track with the triangular joint directly under R9. havent been able to desolder R8 yet. Been on the road today (300 miles round trip) and i'm a bit knackered.

[andywragg]

Its Alive.....



Changed the dodgy caps, replaced D5 and R8 still no joy.

Blasted resin..Thank goodness for spikey implements. After a good clean of all the spaces between tracks, I plugs here in and I now have dirt.

I must say I'm chuffed to bits.....