Phase 90 Build Problem

[Hexjibber]

Hey all,

Just put together a Phase 90 on Pickdropper's 1590A board and having a major issue with it, the only sound I can get is a sort of crackly distortion that degrades quickly and only if I strike the strings hard.

So far I've tried the following;

- Thought it was a toasted IC issue but replaced them all and then used sockets so as to make sure I didn't fry them. At the moment using an audio probe the signal going into IC1 is fine but where it comes out at pins 2 & 6 the signal is degraded and distorted. I get bits and bobs of brief signal further down the audio chain up to a point but only intermittently.

- Tried a variety of wiring set ups, initially the board was just wired to input, output and DC jacks with all grounds soldered together, I then also tried wiring it into a box but just without a 3PDT but no difference so from that it doesn't appear I have any grounding issues.

- No soldering mishaps that I can see on the board under a magnifying glass.

I've never really had an issue like this before so was hoping someone with more experience might be able to tell me how I can diagnose the problem, perhaps I could measure the current until I find an error?

Really struggling with this and feeling very deflated so any help would really go a long way!

Have attached some photos in case anyone can spot something obvious.

Cheers,
Graham

[gtr2]

Voltages?

[Hexjibber]

Voltages?

Hi Josh,

Sorry this is my first time debugging a pedal to this extent, what do you mean?

Cheers,
Graham

[mgwhit]

Read the Rules for getting tech help thread, specifically Jacob's post (second after Bean's).  You need to measure voltage (compared to ground) at several locations in the circuit.  Set your multimeter to around 20V, clip the black lead to a ground point and probe with your red lead. Good starting points on this board are the 9V in pad, the positive leg of C10, the positive leg of C7 and pin 2 of T1.  After that hit your IC and JFET pins.  I appreciate the fact that you audio probed it, but in this circuit an awful lot happens between the input and out put of IC1....  Good luck! 

[Hexjibber]

Read the Rules for getting tech help thread, specifically Jacob's post (second after Bean's).  You need to measure voltage (compared to ground) at several locations in the circuit.  Set your multimeter to around 20V, clip the black lead to a ground point and probe with your red lead. Good starting points on this board are the 9V in pad, the positive leg of C10, the positive leg of C7 and pin 2 of T1.  After that hit your IC and JFET pins.  I appreciate the fact that you audio probed it, but in this circuit an awful lot happens between the input and out put of IC1....  Good luck!

Hi Matt,

Great thanks, my apologies I had not seen that info post before I posted my problem, I will measure all the relevant voltages you mention and post my findings.

Appreciate the assistance, thank you!

Cheers,
Graham

[flanagan0718]

Check this solder joint (see picture), it looks like it might be a bad joint.

[Hexjibber]

Check this solder joint (see picture), it looks like it might be a bad joint.

Hi Mike,

Thanks for the reply, good spot there! This is the photo before I socketed all the IC's, I didn't have one of the socketed version on my phone for this post but rest assured I was very thorough with the socket soldering as opposed to before using them when I was petrified of toasting the chips so only soldered in short bursts!

Cheers,
Graham

[flanagan0718]

Any luck?


Sent from my iPhone using Tapatalk

[Hexjibber]

Any luck?

Hi Mike,

Not as yet, busy with a house move & renovation plus job hunting at the mo so the ol' pedal hobby has taken a back seat for the time being! I will get round to doing my readings at some point soon hopefully!

Cheers,
Graham

[flanagan0718]

Any luck?

Hi Mike,

Not as yet, busy with a house move & renovation plus job hunting at the mo so the ol' pedal hobby has taken a back seat for the time being! I will get round to doing my readings at some point soon hopefully!

Cheers,
Graham

I know the feeling. Good luck on the job hunt.