New (old) Guitar Day! Decapitated Ibanez Axstar!

[DalyTek]

They sound very good. I cannot really find a good way to describe them.
I would say they are very similar to EMGs, with regards to the output and the note clarity, but not quite as "stale" sounding, if that makes sense?

The active EQ circuit makes only the most subtle change, and I think that board is still the culprit. I know it's working, but I think it should be a little more pronounced than it is.

[len]

a K30a is a JFET junction gate field-effect transistor and different than a regular transistor as far as substitution,the spec sheet for it is here http://www.on-ele.org/up/2SK30A.pdf and the NTE counterpart NTE 459 is here http://www.nteinc.com/specs/400to499/pdf/nte459.pdf i'll see what we have at work today

that schematic is wrong as it is shows no transistors and the triangles represent 2 halves of an small 8 pin sort of op amp ic,which would make sense,which i do not see on the pix of the board

[DalyTek]

I got lost after the "a K30a is a" part lol.
It appears it is a different transistor? Is it still something I should worry about replacing since it was in there backwards?

One thing that I noticed is that if I ground the 3rd leg of the EQ pot--(like it originally was)--it starts hissing pretty badly. Not near as bad as it was, but it's still hissing. If I leave that leg ungrounded, it works without hiss.

[DalyTek]

len, I drew up a detailed (as detailed as I can make it anyway) visual diagram of the circuit. I don't understand actual schematics, so bear with my stupidity.
All of the resistors are 5% tolerance, so I just skipped the 4th gold band on them.
If you have Photoshop, PM me your email address and I'll send you the .PSD file so you can dig through the layers and really see what the layout is.
I noticed that there is a capacitor completely missing from the board. Only it's legs are remaining in the little holes, so I think I will need to replace that if we can figure out what it should be.

Thanks again for any help!

[len]

One thing that I noticed is that if I ground the 3rd leg of the EQ pot--(like it originally was)--it starts hissing pretty badly

not to be a wise ass but thats like saying it hurts when i hit my thumb with a hammer
don't do it

It appears it is a different transistor?

yes and no it is not a transistor per se it is Field effect transistor
instead of having a Base,Emitter and Collector ...it has a gate,Source And Drain
too much tecky stuff
my only concern is that the the K30 might and i mean might atomic level breakdown in its junctions (latent damage) and is a weak link that might cause a failure in the future ,but if it works now thats good ,if you feel uncomfortable google mouser or digi key and replace it its prolly only about a buck or 2
i read you think its needs a little more something something
i'll tell you a couple things about that circuit from the drawing you made (nice work btw)
all the semiconductors are rated at 50 volts as are the caps ....
i do not see any type of voltage regulation at all ....soooooooo......
it is might possible to throw a little more juice in there for some extra oomph
i would use a variable dc power supply hooked up to the pos and neg battery terminals via alligator clips and bring it up a couple volts at a time .....see what hapens sonically at each interval and THERMALLY on each transistor,if they get too hot back it off
no harm no foul
i'd stop at 18v ....get the hint? cause putting 18 volts dc on that circuit would be quite easy to accomplsh permanently ,welll until they wear out
would i do it ...yep but i have a whole shop electronic shop where i work and thers really nothing to that board ...even if a trace burns, you have pix of where it went before
have photoshop email addy is [email protected]
that board cant burn up that bad

[DalyTek]

len, I emailed the diagram to you. I'm not sure what the green components are. They are labeled with C# (just like the capacitors are) but they look like a coil wrapped inside the transparent green jacket.
I mentioned the grounding of the 3rd leg because it was originally wired that way, so logic tells me it should wind up back that way when I am finished.
Obviously I will need to find the proper value for the capacitor that is missing. If it's not too hard to locate the parts, maybe it would be worthwhile to fully rebuild the board.
The potentiometer that is attached to this board is rated at 10K B. I'm not sure if that's the correct pot or if it's supposed to be a 25K like on other active pickups' circuits?

I'd just really like to get it fully up and running like it should be. What's you opinion on the best route to go?

[DalyTek]

I had a real diagram drawn up for me, so thought I would share it here and see if len (or anyone else) could help me determine what capacitor type and value should be at C9 (in the middle, just above center)?
I am told it would be something referred to as a "miller capacitor" which usually are very small values (100pF or less.)

Here's the diagram: