Em Drive not working

Started by mattlee0037, May 15, 2013, 11:48:07 PM

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mattlee0037

Ok, so to clarify pin 2 is going to pin 8 of the other switch. The board is going to the common ground, I ran a ground from that sleeve to the common ground, and it had the same problem. Hmm... there's not many things left that it could be.
Thanks for all your help so far too!

Jdansti

Just to clarify:

Pin 8 of the first switch would normally go to your output jack tip, but since you have another effect in the box, it needs to go to the other switch where you would normally connect your input jack tip (pin 2).

The sleeves of both jacks, the grounds of both boards, and the ground from your power jack all need to be connected at one point. That point can the sleeve lug of of one of your jacks, or the ground terminal of your power jack, or a ground point on one of the boards.

The whole thing should look like this:

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mattlee0037

Ok for grounding I have everything on the em drive going to that sleeve and on the booster iI have the centre lug going to the other sleeve which runs to the other sleeve. That's ok right, because its in series I think.

mattlee0037

Wait I might need to take the board grounds from the DC jack to the sleeve

Jdansti

Quote from: mattlee0037 on May 19, 2013, 08:32:36 AM
I have the centre lug going to the other sleeve which runs to the other sleeve. That's ok right, because its in series I think.

Center lug of what?
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Jdansti

Something else I just realized is that you're using all plastic jacks, so you don't have anything grounded to the enclosure that would allow it to act as a shield when you're finished building it. There are a lot of alternatives, but here's the easiest:

1) Take about 3-inches of small gauge wire and solder it to the sleeve of your input jack along with all of the other ground leads.
2) Strip a good inch of insulation from the other end.
3) Remove the nut on your input jack.
4) Wrap the stripped end of the wire around the threads close to the body of the jack.
5) Reinsert the jack so that the bare portion of the new wire is squeezed between the inside of the enclosure and the body of the jack.
6) Replace the nut on the jack.

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mattlee0037

On the booster I have pin five running to output sleeve which rums to Input sleeve. Also both board grounds go to the DC jack should I take another wire from a board ground to sleeve, because another wire won't fit in the DC jack ground

Jdansti

Yes, you can do that. The most important thing is that all of the grounds are connected together. The following should all be tied together, preferably at one point if possible:

Negative power terminal
Input sleeve
Output sleeve
Circuit grounds for all boards
Pin 5 (in your case) of all 3PDT bypass switches

If I understand correctly,  your ground wiring looks like this:




Here's how you test that all of your grounds are connected (besides by sight):
With your power supply disconnected from the box, Set your meter to read continuity or resistance, place one lead on the negative power lug, and place your other probe on each of the points listed above. You should show continuity or very low resistance when you touch each point.
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mattlee0037

Ok cool I'll do this today. Unfortunately though my multimeter doesn't so continuity.

Jdansti

Does it measure resistance (ohms, Ω)?
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mattlee0037

Yes, it does measure resistance, and I connected the grounds, but it still seems to be having the same problem... could it be a dead transistor or diode?

mattlee0037

Also, disconnected first effect, just to be sure it wasn't anything to do with that So I took the pin 2 to pin 8 connection out and put pin 2 of the boost to the output jack tip and disconnected the Em Drive from the input jack tip, and it did the same fuzzy volume drop thing.  :P

Jdansti

If I recall correctly, the booster was working earlier before you added the second board. Did you maintain the ground continuity from the DC jack to both boards, to the input jack, to pin 5 of switch1, to pin 5 of switch 2, to the output jack?  The enclosure should be grounded too, but this could be done when you get everything working.

After you do a visual confirmation of the grounds, follow these instructions exactly as listed:

1) Make sure that the power is disconnected from the pedal.
2) Set your meter to resistance/ohms/Ω. If you're meter doesn't autoscale, set it to one of the lower settings.
3) Test your meter and probes by touching the two probes together. The meter should change from infinite resistance to zero, or less than 1 Ω.
4) Hold or clip one of the probes on the DC jack negative lug and keep it there for the rest of the test. It doesn't matter which probe. 
5) Touch the other probe to a ground point on the booster board.  You should see the meter go from infinite to low ohms just like when you touched the two probes together.

6) You should also get low resistance when you touch the other probe to the following:

-Second board ground point
-Input ring
-Pin 5 of SW1
-Pin 5 of SW2
-Output ring

If any of the points above don't show low resistance, you need to ground that point.
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mattlee0037

Ok will get these tests done tomorrow and report back, and sorry if there was any confusion, but the board has never functioned as it was supposed to.

mattlee0037

Oh I thought I posted! Sorry I checked all points and they had no resistance!

Jdansti

Quote from: mattlee0037 on May 26, 2013, 11:10:36 PM
Oh I thought I posted! Sorry I checked all points and they had no resistance!

No resistance = mucho continuity, so the grounds are all connected. This is good!

This is also where my knowledge is pretty thin in terms of getting your circuits to sound right. Hopefully someone else can pick up the torch and help you troubleshoot the circuits. 
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mattlee0037

Ok I've asked the guy from tagboard effects, hopefully be answers soon! Thanks for all your help in getting the wiring right and the one side working!