comradehoser
Well-known member
For the sake of posterity and avoidance of future builder frustrations:
Well, I did me a troubleshoot. Finished this duophase after being away and plugged it in with anticipation, but no. First, both LEDs were on, no sound except for strangled braps of distorted signal.
Did I want to immediately post a troubleshooting thread? Yes.
But, I did a visual inspection. I said to myself, there's a lot of ICs. Maybe one or more of them is oriented against trend, and I didn't pay attention. And, look at that, yes, the two 1044SCPAs were pointing up when they should have been pointing down, unlike the 10 or whatever tl072 oriented up. A-HA! That's why I socket my stuff, ladies and germs.
Flipped those bad boys around, side A has sweet phasing. Side B, it has no change. Still strangled, still full constant LED.
WTF?
Did I want to immediately post a troubleshooting thread? Yes.
But then I just decided to take some voltages and compare functional and nonfunctional sides since they are identical. Side a transistor, fluctuating voltage in time with the LED, cool. side b transistor, 8v, no fluctuation. Hm! Maybe power, maybe the IC feeding the transistor. Let's look at the schematic and start with the 1044 since that fixed the other side. OK, functional 1044 has -3.25 on 4 and -7.9 on 5. Non-functional has .17 and .798. I notice the 1044 is supplying all of the ICs with a negative and positive rail on pins 4 and 8. All of the functional side TL072s have negative on 4 and positive on 8, none of the non-functional do, so it has to be something around the 1044. Caps are correct; grounds all good. What could it be?
Well, before I started wading into the paranoid weeds of failed or misplaced resistors and capacitors and bad traces, maybe let's just check the IC, even though they look exactly alike so probably not a clone failure. I had a spare one, and subbed it. Well, well, well.
Ta-Dah! Bad chip! (or I effed it up running it upside down or fondling it with my dirty static hands).
Anyway, I have a fully working pedal * pats cool calm and collected self on back *. And it's a good one. Might be my fave phaser so far (Lovetone doppelganger, aion redshift). Last one will be the Chuck D. Bones mods Circulator for a friend.
Now, back to my pile of 6-10 pedals I need to troubleshoot, 12 boards to build, and 12 PTP projects.
Well, I did me a troubleshoot. Finished this duophase after being away and plugged it in with anticipation, but no. First, both LEDs were on, no sound except for strangled braps of distorted signal.
Did I want to immediately post a troubleshooting thread? Yes.
But, I did a visual inspection. I said to myself, there's a lot of ICs. Maybe one or more of them is oriented against trend, and I didn't pay attention. And, look at that, yes, the two 1044SCPAs were pointing up when they should have been pointing down, unlike the 10 or whatever tl072 oriented up. A-HA! That's why I socket my stuff, ladies and germs.
Flipped those bad boys around, side A has sweet phasing. Side B, it has no change. Still strangled, still full constant LED.
WTF?
Did I want to immediately post a troubleshooting thread? Yes.
But then I just decided to take some voltages and compare functional and nonfunctional sides since they are identical. Side a transistor, fluctuating voltage in time with the LED, cool. side b transistor, 8v, no fluctuation. Hm! Maybe power, maybe the IC feeding the transistor. Let's look at the schematic and start with the 1044 since that fixed the other side. OK, functional 1044 has -3.25 on 4 and -7.9 on 5. Non-functional has .17 and .798. I notice the 1044 is supplying all of the ICs with a negative and positive rail on pins 4 and 8. All of the functional side TL072s have negative on 4 and positive on 8, none of the non-functional do, so it has to be something around the 1044. Caps are correct; grounds all good. What could it be?
Well, before I started wading into the paranoid weeds of failed or misplaced resistors and capacitors and bad traces, maybe let's just check the IC, even though they look exactly alike so probably not a clone failure. I had a spare one, and subbed it. Well, well, well.
Ta-Dah! Bad chip! (or I effed it up running it upside down or fondling it with my dirty static hands).
Anyway, I have a fully working pedal * pats cool calm and collected self on back *. And it's a good one. Might be my fave phaser so far (Lovetone doppelganger, aion redshift). Last one will be the Chuck D. Bones mods Circulator for a friend.
Now, back to my pile of 6-10 pedals I need to troubleshoot, 12 boards to build, and 12 PTP projects.