#132875  by Searing75
 Thu Oct 03, 2013 5:18 am
So, I wired up a guitar exactly like Tiger, and exactly like another guitar I have. It will not work??? I get a faint signal, and some strange buzz. It sounds like I am grounding out somewhere? I have changed all of the components and it still is not working! It's the craziest thing. There is not one difference between the two guitars, but the one works beautifully, and the other............nada!?! I am at my wits end :? . The other night I got so frustrated I took a baseball bat and hit my bed over and over, and screamed "Shut up" out my window at some kids that were screaching over and over down the street. :oops: I need suggestions please. I have a multimeter, so what, where, and how should I manage.

Chris
 #132876  by waldo041
 Thu Oct 03, 2013 6:38 am
First I suggest taking a FULL day stepping away from it! Second, know that it will get fixed and work.

After doing #1, take some pics and post them here.

~waldo
 #132877  by Smolder
 Thu Oct 03, 2013 6:39 am
put the black lead on the ground of the jack... use the ohm setting and check continuity at every junction and solder joint along the signal path. (assuming you've already done the highlighter/schematic check process)... you probably have a cold solder joint, or maybe a bad component. Though it's complex for a guitar, there aren't that many reasons you'd lose signal strength. The baseball bat is one way to take a break, but there are a lot of others. Best of luck Searing... you'll get this.
 #132880  by Searing75
 Thu Oct 03, 2013 10:14 am
When I bypass the preamp and the power to it (I run a one spot from my power conditioner up to a 1/8th jack I put in the guitar. This works perfectly on my other jerry guitar), It works. I replaced the effects jack, tried a different preamp, tried powering with a 9V battery, but nothing worked???? I will test with a multimeter tonight. What readings should I see when looking for continuity? Thanks all for your help with this.

Chris
 #132881  by Smolder
 Thu Oct 03, 2013 10:22 am
Searing75 wrote:When I bypass the preamp and the power to it (I run a one spot from my power conditioner up to a 1/8th jack I put in the guitar. This works perfectly on my other jerry guitar), It works. I replaced the effects jack, tried a different preamp, tried powering with a 9V battery, but nothing worked???? I will test with a multimeter tonight. What readings should I see when looking for continuity? Thanks all for your help with this.

Chris
Well you should look for consistency through out... in other words if you get a change in resistance, with pots on full, I'd suspect a problem at that point or before. You could also measure VAC at the different spots when tapping on the pickups themselves.
 #132882  by TI4-1009
 Thu Oct 03, 2013 10:50 am
Ohms is the measure of resistance to current flow through the circuit. If you set the meter to ohms and touch the two probes together you should see 0- no resistance. Probes not touching is infinite resistance- usually 1 (depending upon what you have the meter set to). So if you go from one connected component to the next you're looking for zero resistance assuming you have good connections and electrical flow. Pots are variable resistors, so you should see a change in ohms between two of the pot posts as you turn the knob. You can connect the probes across resistors to measure their value, capacitors "not so much" :lol:
 #132883  by Searing75
 Thu Oct 03, 2013 1:44 pm
Black lead on input jack ground. Red to volume =21.5K. Follow the signal to the Effects loop switch. On volume pot side=21.5k, on preamp side=9.4K Power coming in from 1/8 " jack reads 7.9 mv. This is all with guitar plugged in, and amp on. thoughts?

Chris
 #132904  by Searing75
 Fri Oct 04, 2013 5:34 am
Can't post pics??? So I checked for continuity and I followed the signal from the input jack tip, good to the volume pot, good to the OBEL switch middle left lug, good to the OBEL switch upper left lug, stops there (think that is normal?) then I tested from the tip of the OBEL jack to the OBEL switch upper right lug, good, to the middle right lug, good. I still can't figure this out?????
HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :? :? :? :?
 #132909  by tcsned
 Fri Oct 04, 2013 6:36 am
If you want to post pics you need to load them somewhere on the internet ie Facebook, Flickr, Picasa or something like that then paste the url of the image between the "Img" tags. If that doesn't make sense there's a step by step here:
forum/viewtopic.php?f=359&t=12940
 #132936  by hippieguy1954
 Sat Oct 05, 2013 5:11 am
This is kind of rare, though it has happened to me and you might have heard of it before too. The mini toggle switches can be compromised if a person heats them up too much, too many times when soldering. If there is even a remote possibility that this is the case, I'd change the switch.
 #132937  by Mr.Burns
 Sat Oct 05, 2013 5:37 am
Doesn't your multimeter have an audible continuity alarm? I bought a $10 one that has it, and that's how I check continuity. I put my axe together without once being concerned with actual component values (apart from when I used the values to order the parts). The problem sounds like it probably has to do with a bad solder joint, or maybe a bad switch like hippieguy suggested, but if it were my guitar I'd start with switching to a battery (I realize you already tried that). I prefer the consistency and reliability of a 9V. After that, check continuity and isolate and check each component. You're bound to come up with some answers if you check thoroughly. I find I have less problems like this if I check this stuff while I'm assembling.
 #132939  by waldo041
 Sat Oct 05, 2013 7:29 am
Searing75 wrote:When I bypass the preamp and the power to it (I run a one spot from my power conditioner up to a 1/8th jack I put in the guitar. This works perfectly on my other jerry guitar), It works.
If this statement is true, and you connected the input of the buffer directly to the output of the buffer, then the problem lies in the preamp and/or power supply.
Searing75 wrote:Power coming in from 1/8 " jack reads 7.9 mv.
This could be the problem.

~waldo