[Jukebox-list] AMI TI-1 amp rebuild

[wbabbott at cox.net]

I restore old tube radios also. The basic electronic restoration of a tube radio is a "re-cap"... replacement of all the filter and paper caps. I'm no electronics expert , ie short on theory, long on mechanics. A couple of excellent "How To" sources for replacing capacitors that I used to learn are in the below links:

JUST RADIOS is an excellent link for buying all the caps you'll need for restoring your juke or old tube radio. Also, the best guide for selecting and using the correct caps. EXCELLENT SERVICE...
http://www.justradios.com/captips.html

BRET'S OLD RADIO is an excellent site for getting Bret's VHS tape on restoring old tube radios.  I have his VOLUMN 1 Antique Radio Restoration guide and it's great instructional guide watching Bret clipping out caps and properly replacing them. Although, unlike Bret, Electrolytic Filter caps in Juke Tube amps should be attached to terminal strips to properly secure, unless you want to do the "in-can" procedure outlined by Don.
http://www.bretsoldradios.com/

Britt






---- Don <dontutt at telus.net> wrote: 
> 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
> >> _______________________________________________
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