E-H LPB-1 troubleshooting

[jhicken]

Hi Everyone, my 1st post- although I've been lurking on here for a couple of months reading and learning. what a great information source! Now I'm building my 1st pedal, and I've been trying to trouble shoot an LPB-1 and I would love if someone could help me out a bit.

E-H - LPB-1,
using this layout - http://media.photobucket.com/image/recent/IvIark_2006/DIY/EHXLPB1Turret-IvIark.png

problem-- bypass works fine, but when engaged there is no signal. I made this on perfboard, and have my resistors standing up to save space . I swapped 360R for 330, and 830k for 860k) and .1uf caps for both of the 150nf.

I have successfully breadboarded this, but putting it in an enclosure with wiring a 3pdt and led is all new to me... Initially I thought I screwed up the wiring (I was referring to this website-- http://gaussmarkov.net/wordpress/thoughts/wiring-up-a-1590b/), but after triple checking it, it appears to be correct, and now based on the battery probe I'm thinking it's the CB output...

battery probe = 8.10V. Voltage at board input is 8.08V, and at the board output is 0.03V -- I'm guessing this is the problem? If I probe the leg of the .1uf cap that connects to the 10K resistor, I get a reading just under 8V but when I probe the other one (which connects to lug 3 of my pot), I get the 0.03V reading... maybe a faulty cap? sorry if this is a no brainer, I'm completely new to this and I'm slowly learning more and more.

here are the Q1 voltages (2N5088)
e - 0.28
b - 0.88
c - 7.96

I'm going to take a few pics as well, I'll post those shortly. for troubleshooting, I have removed the DC jack and LED and am just running a 9V battery.

thanks in advance for any suggestions/advice.
james

[jhicken]

sorry, these are kinda fuzzy but best I can do at the moment.



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yellow cable is CB output (going to lug 3 of pot)
blue cable is CB input (from top left lug of 3pdt switch)
red - CB power in (connected to battery strip red)
black CB ground (connected to lug 1 of the pot, and I have another cable going from CB ground out to sleeve of mono output)

the white cable coming from the center of 3pdt switch is not connected (was for LED, but I'm trying to simplify to troubleshoot).



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[pinkjimiphoton]

the substitutions you made won't matter enough to be significant.

voltages look ok. i would double check your wiring with the switch. i can't see anything wrong, but it would appear by the voltages the thing's working. have you tried bypassing the switch completely to see if it works then?

[pappasmurfsharem]

Also it looks like you wire on lug 6 (middle lug bottom row) isnt connected to lug 1(first lug top row) and i dont see a ground wire running to the middle lug (lug 5) assuming your following the wiring from the gussmarkov page.

It should be
Lug 1 -effect in
Lug 2(middle left) -input jack tip
Lug 3(bottom left)- connected to Lug 9(bottom right)
Lug 4(top middle) - connected to led-
Lug 5(middle middle) -connected to ground
Lug 6(bottom middle)- connected to lug 1 (grounds effect input when effect is off)
Lug 7(top right) - effect out
Lug 8(middle right) -connected to output jack tip

[IvIark]

If there is one thing I would suggest, never ever ever ever solder up the switch until you have confirmed the board is working ok.  You can use a small terminal block to make the temporary connections before hand, then once tested you know any problem later relates in some way to the switch.

[jhicken]

thank you for the responses. Jimi- I haven't wired it bypassing the switch altogether, I guess that makes the most sense to try now so I'll know if it is the board or the wiring. I did check the continuity of the switch and it's still good (I read somewhere that they can be sensitive to overheating when soldering).

pappasmurf- I know it's hard to tell because of the fuzzy picture, but I do have it wired as you have listed (brown cable from middle bottom to top left, and black ground cable from center middle going to ring of mono out jack).. does this sound right for the grounds:

1. black battery snap to output jack ring
2. CB ground to output jack ring
3. pot lug 1 to CB ground (soldered to #2)
4. switch middle center lug to output jack ring

on my input jack I just have tip going to middle left lug on switch. my understanding is that the aluminum enclosure will act as a ground point for the input jack... oh, and for the pot I have lug 3 going to board output, and lug 2 going to switch top right.

IvIark - that sounds like the way to go.... for where I'm at I think popping in terminal blocks would save a lot of time overall... I've been beating my head against the wall the last couple of days with this trying to figure out where I screwed up.

thanks again for the help, I can't wait to get this thing up and running... I'll update later today... fingers crossed! Once I complete it, I'm going to try a colorsound one knob on vero board.

[jhicken]

OK- I took a breather from this and worked on a couple of different pedals... I successfully built a bazz fuss running on battery with a dpdt foot switch and a J201 boost with DC power, LED and 3pdt switch (a couple of j201 boost pics below)... BOTH WORK beautifully!!! hurray..

it turns out the issue with the lpb that I wrote about above was a short due to my soldering.... I gotta say I learned a lot from troubleshooting it (even if I did wanna pull my hair out), and it felt so damn good to box up the bazz fuss and the j201 booster and play through them... thanks again for the tips.

james



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[pinkjimiphoton]

right on!! i knew you'd figure it out, nice work james!!
jimi