MXR+ PRBLEMS

[isaac]

HELLO PPL . IM NEW ON THE FORUM , BUT I LIKE TO ASK :

I build a MXR distortion +, from tonepad.com , but i don't have the wiring for JACK's GND , i saw the General Guitar G. layout wiring, but are not same pcb , please if you help me guys .....




Thanks  

[petemoore]

If you're using a metal box 'n jacks you should read continuity from on jack sleeve [Gnd.] and the other jack sleeve. If you read ground continuity between the jacks, a wire from jack sleeve lug to jack sleeve lug isn't needed. [input and output must have ground reference connected.
 Otherwise run a ground wire from cct ground to both jacks.
 If you want power to be lifted when the input jack has no 1/4 mono plug inserted, run PS ground to the ring [this uses a Stereo input jack] and circuit ground to sleeve. when the mono sleeve connects sleeve and ring, the PS circuit will be completed. Pull the cable plug from the input and the ring/sleeve ground link will be broken.

[isaac]

thanks petemoore ...

the Jacks are metal , Stereo IMput and Mono Output , i solder the GND from Jack Lug to GND of the PCB ( Not the battery ) ...

im going to test later because i need to go back school ( my band have a Jamming ) ....... Oh by the way my band called ABADDON ( Spain )

[petemoore]

thanks petemoore ...

the Jacks are metal , Stereo IMput and Mono Output , i solder the GND from Jack Lug to GND of the PCB ( Not the battery ) ...
 >>>the input jack, stereo, it's Sleeve lug goes to CCt ground, the ring goes to the PS.

im going to test later because i need to go back school ( my band have a Jamming ) ....... Oh by the way my band called ABADDON ( Spain )

>>>Use the DMM, the Stereo jack, and a cable plug [1/4'' mono], set the DMM to beep mode, and see what connections happen between ring and sleeve when you plug the plug in / unplug the plug...it should make connection between ring/sleeve with plug in,,,used as the PS ground lift [in this case].
 >>>To test PS, clip on a tested battery [~9v], plug a 1/4'' plug into input, then test the voltage potentail between ground an the Supply pin [V+] of the opamp...it should be powered up [to ~9V...just teeny bit less than without the Cct. drawing current from the battery].

[isaac]

I solder the GND from jacks to the PCB GROUND and when i push the Sw my guitar have clean bypass , but if i push again NO SOUND or Effect !

im going to draw what i do, is more easy to explain .... and how i can post a image here ? i don't have web space to post ....


sorry for silly questions !

[petemoore]

Tips you may choose to follow...
 Lose the jacks and switch till the cct board is working.
 Make a test jig,...a box with 2 jacks.
 both jack sleeves [gnd.] go through a wire and terminate at an alligator clip, use the clip to clip ground connection from jacks to board.
 Each jack tip gets a wire 'n alligator too [input and output] clip the alligator input wire to Cct input, the output wire to output. Connect battery.
 If you clip the input wire/clamp to the output clamp, and sound goes through the testjig, you know that works...and have eliminated 'peripheral' sources of malfunction, you can concentrate on the board workings. ALso you won't have a 'gangly' mess where shorts and broken wires are more likely to occur.
 I'd type out how to test switch and jacks, but think it's really easier to simply eliminate whatever you can, narrowing the focus to where 'one' [maybe more] problem is...with 'extras', you could have the one' thing fixed, have a working board and not know it...going on looking for fixes where nothing's actually wrong.
 Anyway, for now, just take voltage readings ont he chip, could be that shows a problem exists on the board....
  Black DMM lead to ground, DMM set for 20v range, note the voltage reading of each opamp pin [1-8], and post them. Always include actual battery voltage [take a reading] with pin voltage posts.
 Debugging page has lots of good's, audio probe is easy/cheep to construct, with a testjig, it's as simple as  clamping a DC blocking cap [.1uf or bigger, smaller if that's what you have]  to the output wires alligator clip.

[isaac]

Thanks Peter i follow your guide and works well the jacks are in GND ,

but i think i have malfuntion , when i plug the guitar sounds well , but when i press the Switch , stay in same sound but have a rain sound , i dunno how to explain, not feedback , just like water fall


im going to check the solder again