ampage
Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!

 
Listen to great tunes streaming live right now!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  

How to tell if a P.U. is D.O.A.


 
9/13/2000 6:30 PM
Adrian How to tell if a P.U. is D.O.A.
Hi ya'll!  
 
I have a guitar that may have a bad P.U.. I am hoping the crew here can help me determine the FACTS!  
- Guitar is a 70's Epi Coronet(?) with two metal covered humbuckers.  
- For a while I was using this Guit. as a test instrument for homebrew effects and they all sounded like they had a nasty scrapey distortion on hard hit chords.  
- when lowering the front HB it failed - no more output - bridge PU is fine and bridge only switch position is fine.  
- the switch checks out for continuity as do all the grounds i can find.  
 
I can find no wiring fault using my level of sophistication in trouble shooting (i have never really worked on guitars, just EFX, and a little amp work)  
 
Before I go and buy a new PU what should I check?  
I am a big cheepie and would positively HATE to buy a PU and then find a different problem.  
 
Pointers extremely welcome!  
thanks,  
- A
 
9/13/2000 6:35 PM
Liam
email

Adrian,  
 
Disconnect the pickup leads and check for continuity across the pickup itself. Should be between 5 and 15 k ohms. If you get open or short circuit the pickup has a problem.  
 
Pretty much all pickups are repairable - but it can be more trouble than it's worth.  
 
Liam
 
 
  Sunday
Book Of The Day The Ultimate Tone, Volume III by Kevin O'Connor
Have you ever wondered if there is a better way to build a Bassman, Champ, Plexi, an 800, AC-30, Bulldog or Portaflex? Or you wanted to build an SVT with off-the-shelf parts? How about a master-volume amp that doesn’t change tone with the master setting? Everything you need to know is right here, including: proper grounding techniques, wiring methods, and mechanical considerations. Eighteen chapters cover the “iconic” amps everyone knows and loves, with schematics and layouts for each, along with the technical history of the product. Eyelet-board and chassis-mounted tube socket construction is used throughout, for easy servicing and modding. TUT3 is very accessible even if you cannot fully read a schematic and is a "must have" if you are going to build an amp for your self.

Note: The Ampage Archive is an Amazon Associate site. A small commission is paid to the site owner on any qualified purchase made after clicking an associate link such as the one above.
 
9/13/2000 7:59 PM
Adrian How to tell if a P.U. is D.O.A. !
Thanks Liam - I'll do as suggested. If it is open or shorted I may try a repair even though I'm happy to buy a new PU if needed. I like getting into things - if it is broken I have nothing to lose and much to gain in the way of knowledge!  
For example I fixed a non-functional key on an olde synth i have - it sure makes for a better keyboard.  
Thanks again,  
- A
 
9/13/2000 8:33 PM
Glen H.
email
Crestwood
Your Epi is likely a Crestwood model...  
 
Glen H.
 
9/13/2000 10:42 PM
Adrian
Double Cutaway, Black, Les Paul-type headstock. white/clear pickguard. several pieces of wood comprise the neck, white dot inlays, Les Paul-type bridge.  
2vol 2tone knobs plus the selector down near them so you can accidentally hit it.  
Is that the Crestwood?  
Curious....  
- A  
Thanks Glen.
 
9/14/2000 5:22 PM
Glen H.
email

That sounds like the one (just can not recall the headstock shape). Body thinner that usual. Cutaways  
different from a LP jr. & Melody Maker. "C" with line through middle on either pickguard or truss rod cover. Two semi-cheezy humbuckers (no offence meant here, the PU's are just not up there with the standard Gibson 49X's...)  
The Crestwood had a few permutaions over the years, from fixed bridges to whammy bar setups. Also, some had chrome hardware, others had gold. Finishes varied from sunburst to solids. Some had set-necks, others were bolt-ons.  
The guitar player for Hole used to use one a few years back. I really like the design, very cool!  
 
Glen H.
 
9/18/2000 8:50 PM
Adrian
Thanks Again for the Info.  
I did manage to fix it and learned something good in the process.  
this: the "continuity" setting on a DMM may read good even when a connection is not good enough at low signal.  
- Duh - Use resistance! or at least in combo.  
The "hot line from the PU was dead at the pickup end due to a bad joint to begin with and the pressure of trying to lower the pickup against this block which the neck bolts on to. the cavity is too shallow as a result of the thin body. the front PU can't go even fairly low.  
 
I guess it is a budget guitar for a reason! Still much better that the real cheap guitars of the 70's!  
Hondo , anyone?
 
   Page 1 of 1