This is a Two-fer question.

[PaulDouglas]

I just bought a "broken" Schecter 004 Diamond series bass. The Active mode does not work but the Passive does; minus the tone controls.
Question#1: Any tricks to tell if the pre-amp is shot or a wiring issue? Visual inspect did not see anything loose.
Question#2: Has Thru the Body or Over-the-top bridge for stringing. In 20 years of playing, I have never used a Through the body string set up before...what's the (sound) difference?

[john grey]

1.) Get an inexpensive voltage/resistance meter (DIMM), preferably one that has more features than less (transistor/capacitor testing ability, etc). Begin by determining if components are viable & function to spec. The pots often are tested from the middle pole to the attached pole (3 connections to each pot / 6 or more for duals). IF you haven't used a meter previously - READ the instructions to achieve the greatest level of testing. A pre-amp is not particularly complex; however SOME use smaller components than others & some use PC boards to save space. Turn the pots, throw the switches & make sure you have power.....Do NOT forget to ascertain that power is GETTING TO the unit. Assume nothing; go from simplest concept to more complex. THINK of how the unit operates. If you do not understand signal amplification; read a simple digression on it (on the internet) so you understand what should be receiving power (& where), what that power should accomplish, & adjustments to same (& signal).

IF the features [on the meter] are minimal; find a meter that will signal (beep) if you have a short or clean connection. Go through the unit in a very organized fashion, skipping nothing. This obviously will tell you what issues are presented. IF the unit used SMD (surface mounted devices) mini boards simply sharpen the probes and use a magnifying glass. To test transistors that are in-place obtain the specs of the transistor (via the internet) and measure the resistance and viability of diode(s) within for the type of x-istor (MOSFET, Darlington, power x-istor, etc). You will need a magnifying glass to read the type # imprinted on the unit. IF you can obtain a schematic of the unit....all the better.



2.) The sound difference is (like most things musical) very subjective. The difference may appear as more or less sustain or tonality. However I (personally) don't believe it has as great an impact as some folks believe when compared to other issues involving string / body vibration and pup sensitivity. The vibration of the steel string is being picked up by the electronics. The vibration of the wood itself may have some impact therein but it's less than what occurs from nut to bridge and TYPE of wood. YMMV.

[PaulDouglas]

Thanks John....Schecter Help emailed me a "Most likely" schematic but it was not all that close. They discontinued this line are replaced it with StarGazer 4 -- and thats all EMG pickups now (mine are Schecter's own). I'll try some of your suggestions but I'm so savy with electronics that I still test 9v batteries with my tongue!

[john grey]

You can DO IT! All that you're doing is testing components one by one and working in a logical order; then re-checking. If you are relaxed and careful; you'll be successful!

The complication may come when you need to make a substitution for a component that is manufactured to size/space tolerance or is unique some manner. but with dedication, you will be successful. It's easier than it superficially appears. IF the problem appears on a PC-board, address that if it happens. There ARE ways to work with even very tiny SMD components - with the correct tools (which are not too expensive either)!

Best of luck: take your time & be patient. You MIGHT just find it's simpler than you thought!

[JTE]

String-through versus top-load is such a common issue (with absolutely no new revelations) that it pops up about once a month. Do a search, because this IS one of those "oh, no!! Not again!" issues.

John