Print Page - Turnabout- Verified

Title: Turnabout- Verified
Post by: playpunk on April 11, 2016, 12:05:49 PM

I'm in a rut as far as building goes. My last 3 projects have not worked, and it is ticking me off.

Most recently, my turnabout from ep has no sound.

My voltages are goofy- fluctuating on pin 1 between -.5 and .6.

Audio probing gets me clean audio through gain pot but nothin after.

Here are some pictures

(http://uploads.tapatalk-cdn.com/20160411/f95ed01ba4da8ff28ca950271234b7eb.jpg)
(http://uploads.tapatalk-cdn.com/20160411/14e735b0bb7532d81e90e7adab40d853.jpg)
(http://uploads.tapatalk-cdn.com/20160411/cc309d61317deea3cd517557683bddd5.jpg)
(http://uploads.tapatalk-cdn.com/20160411/fbad8db2bea22319f4f1b9efa914f650.jpg)(http://uploads.tapatalk-cdn.com/20160411/d1dc552fdcf989775861ca5cf0e474ef.jpg)

Sent from my iPhone using Tapatalk

Title: Re: Turnabout- no sound
Post by: Droogie on April 11, 2016, 03:00:39 PM

The values that are visible appear to be correct resistor-wise; orientation of electros also good. Might check film cap values. Can't see the pot values well, but is Hair B25k as in the build doc. Looks like it might be B5k? Otherwise reflow and check very carefully for bridges—i.e., the usual stuff. Hope you get it working!

Title: Re: Turnabout- no sound
Post by: blearyeyes on April 11, 2016, 05:16:16 PM

So, you're getting audio at pin 3 of the gain pot and NO audio at pin 6 of the IC?
Check C5 and R6 for values continuity and solder bridges.

Title: Re: Turnabout- no sound
Post by: playpunk on April 11, 2016, 06:55:07 PM

Yeah. I will check those later

Sent from my iPhone using Tapatalk

Title: Re: Turnabout- no sound
Post by: blearyeyes on April 11, 2016, 07:27:36 PM

I hope you can get this verified cause I want to build one. Looks like a good "first etch" project.

Title: Re: Turnabout- no sound
Post by: Boba7 on April 12, 2016, 03:03:22 AM

Yeah some solder joints look quite suspicious to me... Could be bridges (even the tiniest...), bad soldering, etc.
Hope you get it working! I'm quite tempted to build one too :)

Title: Re: Turnabout- no sound
Post by: playpunk on April 12, 2016, 12:01:00 PM

Ugh. That pot is a 5kb, and I am going to check the rest of the values tonight. And reflow. My solder ninja skills are not good enough for etched boards, I guess. I got so used to the nice solder mask

Sent from my iPhone using Tapatalk

Title: Re: Turnabout- no sound
Post by: Boba7 on April 12, 2016, 04:21:25 PM

On your pictures, it looks like there is a solder bridge between pin1 of the IC and ground. Also the drain of Q1 might not be very well connected to the circuit. And did you buy the 2N7000 from Tayda? I recently had problems with the 2N7000s I received from them.

Title: Re: Turnabout- no sound
Post by: blearyeyes on April 13, 2016, 07:32:53 AM

Quote from: playpunk on April 12, 2016, 12:01:00 PM
Ugh. That pot is a 5kb, and I am going to check the rest of the values tonight. And reflow. My solder ninja skills are not good enough for etched boards, I guess. I got so used to the nice solder mask

I'm right there too. Really a different style of soldering.

Title: Re: Turnabout- no sound
Post by: Boba7 on April 16, 2016, 06:32:10 PM

I can confirm all the 2n7000 I received from Tayda recently are faulty. Maybe that's your problem.

Title: Re: Turnabout- no sound
Post by: playpunk on April 16, 2016, 09:20:29 PM

Could be but I got those a while ágo and I think the others are ok. Gonna get back after this tomorrow

Sent from my iPad using Tapatalk

Title: Re: Turnabout- no sound
Post by: playpunk on October 23, 2016, 09:06:16 PM

Hey, just got back after this. It's working now- makes me think my testing rig is the problem!

Sent from my iPhone using Tapatalk

madbeanpedals::forum

Projects => Tech Help - Etcher's Paradise => Topic started by: playpunk on April 11, 2016, 12:05:49 PM