@drseamus
Forum Replies Created
-
Posts
-
Voltage at left side of R8 is showing 8.96v when using a one-spot type of power adapter.
Gave up after an hour or so and swiped one of the GPCB 3pdt daughterboards from the Super Drive 70’s build that I had planned. Got that all wired in and the LED lit up as expected. Guess I’ll be sure to pick up a few more for the other GPCB projects I have upcoming.
Thanks again for all of your help, Billy!
Getting continuity between 3pdt lugs 4 & 5 in effects mode, also getting it from left side of R8 to the LED anode pad (3k3 resistor… measured at 3.28k, so not far off). Same with LED anode to center lug on 3pdt. Voltage at left side of R8 is showing 8.96v when using a one-spot type of power adapter.
Interestingly, I cleaned between the lugs of the 3pdt with a cotton bud and some isopropyl alcohol, and then ran a screwdriver between them just to be sure. And when I touched lug 4 with the screwdriver, the LED faintly lit (with power connected to the one-spot). And when I connected lugs 4 and 7 with the screwdriver it lit up fully. I’m guessing there is some sort of grounding issue on the 3pdt? Or would this be further up on the PCB?
Dang. I think I’m close here.
Fought with this thing for awhile last night… reflowed all suggested joins, cleaned up the board again for any potential stray flux… still getting the same result.
It’s a clear white 3mm LED, which i believe has a forward voltage somewhere around 2.75 – 3v. Dunno if that would be the culprit… I used a single color “warm white” LED in the GPCB BMP OpAmp project and that one lights when the circuit is engaged. Although I used one of the 3pdt daughterboards in that build.
I did notice when I removed it from the enclosure (yea, I know… “rock before you box”) it would produce a loud buzz/hum rather than getting signal in bypass or when engaged. So could there be a possible overall grounding issue? I’ve done a number of boards from PedalPCB that usually work outside of the enclosure, so I’m assuming those PCB projects are designed differently.
Considering just pulling the offboard wiring and getting hold of another daughterboard, but would like to avoid if it is possible to wire with the LED directly to the PCB.
Ok cool. Thought I had removed it somehow!
Removed the lead from S6 to pad 6… getting sound in bypass and when engaged, but the LED still refuses to light.
Got out the DMM and did a diode test by connecting + to the center pad on D2 and – to the one on the right (non-white) and the LED lit up. So I managed to get that part right.
S4 is the blue lead connected to pad 4, S5 is the yellow one connected to pad 5. Cleaned up things a bit with some isopropyl alcohol to make sure i’m not getting a short around that area.
I’m probably missing something painfully obvious here, so I appreciate all the help.
Ok.. although I was working with the Mini-Me 2020 version build doc (https://guitarpcb.com/wp-content/uploads/2018/06/Mini-Me-2020-Build-Document.pdf), which does not have a D5, but rather R31 (47 ohm) in that position. Prior to assembly I had gone through all of the MM version docs to confirm it matched the PCB layout/illustration.
If I were to place a 1n5817 at R31 on the 2020 version, would it rectify the problem and still function?
My soldering skills are still a work in progress, so probably best I stick with the sockets.
That looks like a much cleaner solution for LED placement. Adding some shrink wrap to my Tayda cart now. Thanks again!
Looks like putting a little bend in each leg of the transistor got it to seat and hold a connection much more reliably. Will get out the iron a bit later and try tacking it in with a bit of solder. Thanks Cybercrow! Definitely a trick I’ll use in future builds.
Would you recommend just soldering in the transistors (silicon ones, anyway) rather than socketing them? Or is that asking for trouble if I hold the iron on there slightly too long?
As for the slight hum, it’s not really all that noticeable when you’re playing. Just figured I’d ask while folks were kind enough to respond to my questions. Was going to give this to a friend of mine and wanted to button it up as best I can. No other pedals in the chain at the moment. But I’ll double check those LED legs. That’s probably a weak point, as indicated by my inelegant solution of electrical tape and blue tac.
Thank you both again. Swapped in a new switch, wired it up and the tremolo is now working! No thanks to a socket that only holds onto Q3 after wobbling it a bit, but I’ll figure something out.
There is a bit of hum/buzz when engaged that you can hear with the throb of the tremolo. It quiets a bit when using a humbucker equipped guitar, but still there. Is there something I perhaps need to adjust, or is that just the price of admission for this circuit? I’m using a T-Rex Junior isolated power supply, but tried a one-spot style wall wort and got the same result. None of that noise when in bypass. Perhaps I chose the wrong type of component somewhere along the line?
Ah! Not sure how I missed that. Thank you both! Guess I’ll save that 3PDT daughterboard for the Mini Me Chorus
Thanks Barry! Looking at the Paypal receipt now, just realized that i’ve ordered a number of parts from your shop. I guess I’m headed in the right direction then!
Was able to sort out that I had the 9v hot on the wrong post to the power input jack, and added a resistor to the “clr” part of the 3pdt wiring board. Now the LED will light up when the effect is engaged, and the clean signal comes through when in bypass mode.
But when the effect is engaged all I get is a loud buzz/hum that will increase in volume until around 12 o’clock on the pot, then it changes frequency slightly around 4 or 5 o’clock. Have I completely fried the circuit with sloppy soldering?
I’ve traced back the wiring to the input and output jacks, power supply, and to/from the main board and it looks to be as directed in the instructions. And I can’t seem to find anywhere that has excess solder creating a bridge where it shouldn’t be.
I’m definitely enjoying the build, but man is this frustrating.
Thanks again for everyone’s help on the OKF. Got everything wired into the enclosure, but now only getting a loud buzz when the effect is engaged (nothing when in bypass). When engaged and the knob is turned, the buzz will get louder/softer as you rotate and the LED will not light.
I used the 3PDT board and wired the LED to that (tested it with a multimeter prior to soldering that in and functional), so I’m thinking perhaps I need to add a resistor (wasn’t included in the kit though). Using a yellow 5mm LED… it read something like .22 on the meter. But the buzz/hum, I’m not quite sure where to start.
Would one of you kind folks out there be able to point out where I’ve gone sideways here?
