[Jukebox-list] AMI TI-1 amp rebuild

[Don]

OOPS had to add a little bit at end of my comments...


> Further to Jay's technical comment I would add that if you are 
> willling..... you can pop the TOP off the cans, drill and scrape out the 
> contents, remove the 3 or 4 terminals at the bottom, clean up the inside 
> walls of the can..... then install as many new electrolytics inside the 
> can as will fit. Run their leads out the bottom thru the holes left after 
> removing the old terminals. Leave the lead wire for each cap long enough 
> to reach new tie points that you'll have to make. Of course you must 
> remove the can to do this. Before putting back you mix some two part epoxy 
> spread a puddle of  it on flat wax paper and set the rebuild electro can 
> upside down in the puddle. Next evening come back trim off excess. Spray 
> paint can top silver....  et voila, as you can see in the following 
> picture.... its is hard to tell a cap craniectomy was performed... :-) 
> These two caps only have one electro apiece, inside as you can tell from 
> only a black (NEG) and red (POS) wire protruding.
>
> http://www.donsradiomuseum.com/images/TonyRogers6R631-02.jpg
>
> PS. The electros in above picture have just come off  the wax paper. The 
> cured epoxy now needs to be filed, sanded and painted. If the can has a 
> little groove part way down the side, from the top, I use a copper pipe 
> cutter as a "can" opener.  Almost impossible to tell anything was done 
> when I finish...... also, I lay a little fiberglass mesh cloth in the 
> epoxy resin for extra strength.
>
> Cheers,
> Don
>
>
> ----- Original Message ----- 
> From: "Jay Hennigan" <jay at west.net>
> To: "Jukebox mailing list" <jukebox-list at lists.netlojix.com>
> Sent: Friday, January 26, 2007 12:06 PM
> Subject: Re: [Jukebox-list] AMI TI-1 amp rebuild
>
>
>> 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
>> _______________________________________________
>> Jukebox-list mailing list
>> Jukebox-list at lists.netlojix.com
>> http://lists.netlojix.com/mailman/listinfo/jukebox-list
>
> _______________________________________________
> Jukebox-list mailing list
> Jukebox-list at lists.netlojix.com
> http://lists.netlojix.com/mailman/listinfo/jukebox-list