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hey,
just finished building the EA tremolo, everything works as it should, the kill switch and the corresponding LED’s all work and the level knob works as well, but the rate and depth knobs don’t do anything. any help would be appreciated. thanks.
it does not flash, only solid greens and reds
Double check you haven’t accidentally mixed your transistors up Q4 should be a 2N5088 BJT
Q1 2N5457 fet
Q2 2N5088 BJT
Q3 2N5457 fet
From what I can see all your values and orientation looks correct
The LED D1 should flash in time with the rate knob indicating the LFO is working
You should get a pulsing voltage on the collector of Q4
Some of your solder joints look like they may be dry
I’d reflow all of your solder joints holding your iron on each for around 4 seconds until you get a nice flow removing your transistors from their sockets before you reflow
What temperature do you have your soldering iron set to
First check if you get a pulsing voltage on Q4 collector
still not working
double checked the transistors and they are all where they should be, reflowed the the joints, I have a 40W Hakko iron and I don’t have a voltage meter
also, there was an extra 2N5088 in the kit and I put that in Q4 to see if that would do anything, but still nothing from the rate and depth knobs and no flashing led
I’m not sure if this helps, but try adjusting the rate pot just a bit at a time and remove / add power to the pedal each time until you begin to hear the effect and then you can fine tune it.
This worked for my build. Hope it helps!
Billy will get you there!
Do I see a wire missing from E to SW2?
E is unused, which is how it’s supposed to be according to the wiring diagram (with the kill switch) in the instructions, I think
Darn! I should have read the build doc more closely! I’ll shut up!
nooo I appreciate u trying to help!
Bafo without voltages it’s a case of reflowing solder joints
If you knew for example what voltage you were getting at Q4 collector you could trace it back to find the fault
In the build doc there’s a circuit block diagram and short explanation telling you what each section does
With D1 illuminating but not flashing with the rate pot is an indication the LFO isn’t functioning if that’s the case then Q3 may not be getting the necessary voltage to work either meaning no depth control
I’d advise reflowing all of the solder joints in the LFO section including D1 and the 3PDT connections everything in the block diagram green section
Any joints that look dull grey ball like or crumbly for want of a better word if that doesn’t work I’d reflow every joint removing the transistors from their sockets as I said earlier
Before I used a temperature controlled iron I used a 30W iron I’m not sure if 40W may be too hot just touch your joints until you see the solder pooling nicely making sure you get a good connection between solder pad and component leg
I’ve reflowed everything, I’ve noticed when I plug the power in the LED flashes once or twice and I can get it to flash a little by gently tapping Q4, but I’ve still got no effect. here’s a better photo of the pcb after reflowing everything.
Make sure Q3 and 4 are located securely in their sockets
Try swapping Q1 and 3 or if you have an extra fet use that for Q3
As I’ve said without a meter it’s difficult to know where the problem lies you can buy decent meters fairly cheaply go for one with a 10M input impedance it’s definitely a requirement for pedal building
Did you reflow your 3PDT connections from S4, 5 and 6
I did reflow everything on the 3PDT and everything seems to be secure, Q4 seems to wiggle a bit with both 2N5088’s and that seems to make the led flash, but I still can’t get the effect to sound. I will pick one up today, how would I test the components? obviously never used one.
Fig mentioned the FETs where did you get your 2N5457s from
If you got them from Barry they’ll be genuine
It certainly sounds like an intermittent fault try holding Q4 into it’s socket to ensure a good connection or bend it over slightly in its socket, to see if you get the LED flashing then try Q3 set the rate pot to about halfway
Its usually something simple once you get your meter we can give you instructions
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