[Jukebox-list] AMI TI-1 amp rebuild

[Jay Hennigan]

bakerrj2 wrote:
> I am in the process of rebuilding the amp of my TI-1.  All bad resistors and diodes have been replaced and am currently replacing the caps from a kit that I got from Vern Tisdale.  (Thanks Vern for lableing each cap per the schematic.)  Replacing the caps is pretty straight forward except when it comes to the "can" type filter caps.  I would like to leave the old "cans" in place for appearance purposes and install the new caps below the chassis.  The problem is that there are other terminals besides the caps pos. and neg. leads attached to the existing caps that I am unsure what to do with.  They don't seem to appear on the schematic.
>   
> Can I attach the new caps to the existing terminals or should I install new terminal strips and move the pos. and neg. leads to these strips?  If so will the other attachment points have to be moved as well?
> 
> As you can tell from the above question,  I am a rank rookie in this endeavor.  Any help offered will be greatly appreciated.

The can style capacitors often contain several capacitors within the one 
  can assembly.  The negative for all the caps is the can itself, 
connected to the four (three for the smaller cans) twisted lugs around 
the outer diameter that hold the can in place.  This is *USUALLY* 
chassis ground, unless the can is mounted on a fiber insulating baseplate.

The positive terminal(s) are in the center.  The capacitors within the 
can may have different values, so it is important to match the 
replacement caps to the correct section.  You can do this by tracing the 
wires and matching to the schematic, and also by carefully examining the 
base of the can and the markings on the can itself.

The positive terminals protrude from a fiber insulator at the bottom of 
the can.  There will be a shape punched out of the insulator for some of 
the terminals, either no punch, a triangle, a square, or a "D" shape. 
The printed markings on the can will indicate the value associated with 
each symbol.

On a multi-section capacitor, the schematic will use a letter suffix to 
denote the sections.  So a single can may have four capacitor symbols on 
the schematic, like C401A, C401B, C401C, C401D.  This means that you may 
use up to four individual replacement capacitors to replace one can. 
Vern's parts are probably labeled with the complete schematic designator 
including the suffix letter.

You will need to remove all of the wiring from each non-grounded 
terminal on the existing can and relocate it to a terminal strip. 
Leaving the old capacitor connected to the circuit is asking for 
trouble.  It's certainly OK to leave it in place physically for cosmetics.

--
Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
Impulse Internet Service  -  http://www.impulse.net/
Your local telephone and internet company - 805 884-6323 - WB6RDV