SOLVED Me again...........Tayda EA Tremolo PCB not working

[Jeff C]

Hoping I don't set another record with this one, but I've just finished building an EA Tremolo from a PCB from Tayda. The Tayda forum is useless. No answers, no activity. So, I hope the patient and helpful folks on this forum who got me eventually across the Cobalt Drive finish line (which by the way sounds fantastic!), can figure out what my problem is. Once I finished it and plugged it in, I got audio but no effects. The LED stays lit up whether the switch is off or on. Volume trimmer potentiometer seems to work fine. I do have the input and output jacks wired correctly p), and am getting positive (not negative ) 9 volts to the board. I've posted four pics below (figured out the magnifying bar on the mag-lite app -doh!). Given my transistor trauma of the Cobalt Drive build, I'm suspicious of mine on this one, so I took some close up pics of those. They Tayda build instructions were confusing. https://www.taydakits.com/instructions/ea-tremolo/pages/designators-and-components--43. For one, it lists a C4 cap, but there is no place for it on the PCB. It also says to use the N5457 and the SMD for Q1 and Q3. Tim (Fig) told me to use one or the other so I used the 2N5457, perhaps unwisely. They look pretty gnarly in the pics.
Here are some voltage readings from the transistors:
Q1: G: 9.3; S: 5.65; D: 4.46. Q2: E: 2.24; B: 2.8; C: 2.18; Q3: all 0's (hmmmmm); Q4: E: 0; B: 4.61; C: 2.55.
Also, C2 reads 4.4 on the negative pin and 5.6 on the positive one.

I tested with the audio probe and get a signal most everywhere but nada from any of the pot pins.....

Any suggestions on where to start would be appreciated! Tks.

Jeff

 

[jimilee]

They looked pretty good to me. I had good light but didn’t magnify……..next time for sure! Tks again, Chuck.

Congratulations! That fixes sooo many problems, that should be your go to. It is mine.

 

[Username123]

They looked pretty good to me. I had good light but didn’t magnify……..next time for sure! Tks again, Chuck.

I find that the magnification can help with spotting bad solder joints. On my most recent build I noticed that a few of the joints looked great, but then with magnification they definitely looked cold, so I reflowed them.

 

[MichaelW]

Well, as I've recently learned even solder joints that look good can still be bad. Visual inspection is just the first step. If in doubt at all, reflow.

 

[Chuck D. Bones]

If you can't tell a solder joint is bad by visual inspection, you're not looking hard enough. The solder has to wet to both the pad & the lead. It's possible for the solder to form an nice conical mound and still not stick to the lead. Solder joints that will be obscured by other parts (pots, switches, etc.) need to be inspected before they are obscured. I normally inspect several times during the build. Install SMD parts, inspect. Resistors, inspect. non-electro caps, inspect. Thru-hole semiconductors, inspect. Yadda yadda yadda. I can slap a board together and most of the time it will work. But, if you've ever been plagued by intermittent joints, then you will fully appreciate the value of inspection.

 

[music6000]

You should be able to spot bad solder joints visually. Maybe better light and more magnification would help.

Are you suggesting some Members may need to invest in a set of magnified Glasses, the gall of it!!!

 

[music6000]

If you can't tell a solder joint is bad by visual inspection, you're not looking hard enough. The solder has to wet to both the pad & the lead. It's possible for the solder to form an nice conical mound and still not stick to the lead. Solder joints that will be obscured by other parts (pots, switches, etc.) need to be inspected before they are obscured. I normally inspect several times during the build. Install SMD parts, inspect. Resistors, inspect. non-electro caps, inspect. Thru-hole semiconductors, inspect. Yadda yadda yadda. I can slap a board together and most of the time it will work. But, if you've ever been plagued by intermittent joints, then you will fully appreciate the value of inspection.

No ones gonna tell me if my Soldering is any good, I've built 200 plus pedals & never had an Issue!!!!!!!!!!!!!!!!

 

[Jeff C]

Well, now that I’ve overcome my deficiencies with the Tremolo, it’s back to the Magnetron. I’ll start a different thread, though…….

 

[Chuck D. Bones]

Save yourself 79 more posts and do the inspection.

 

[Jeff C]

You should be able to spot bad solder joints visually. Maybe better light and more magnification would help.

Chuck, in case you weren’t following the Magnetron saga, got it fixed in “only” 50 posts. I’m improving even more!

 

[EGRENIER]

Chuck, in case you weren’t following the Magnetron saga, got it fixed in “only” 50 posts. I’m improving even more!

So I guess the inspection only saves 29 posts

Joking aside, get a proper setup to hold the board, either third hand helps with rubber clip of one of the PCB holder style I posted in the other thread. I think many of your problems comes from grinding/scratching the path off the PCB... Keep metal away from the board, store your board properly to avoid other damange.