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  #61  
Old 11-09-2017, 04:48 PM
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wa2ise wa2ise is offline
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Sometimes I misread the thread titles, here I first misread "porthole" as "portable". Wonder if Zenith ever made a portable porthole.
Like those GE locomotive like portables, except with the entire round CRT exposed.
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  #62  
Old 11-09-2017, 08:23 PM
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Quote:
Originally Posted by wa2ise View Post
Sometimes I misread the thread titles, here I first misread "porthole" as "portable". Wonder if Zenith ever made a portable porthole.
Like those GE locomotive like portables, except with the entire round CRT exposed.
There was a 12" table set IIRC 1950 model year in a leatherette cabinet...Not sure if they had the stones to add a handle and call it portable.

IIRC MacDonald had the engineers adapt a table model porthole chassis into the back seat of his limo so he could watch TV on the go....Some electronics mag of the day had a write up on it. I bet he let them do the article as a way to put out feelers to see if there would be a car-tv market.
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  #63  
Old 11-09-2017, 09:47 PM
Crist Rigott Crist Rigott is offline
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I started on the main chassis and the E-Caps first. I removed C1 and C3. When removing them, I broke off some of the twisty mounting tabs. This is usually the case. Once is a great while, I'm able to remove a can without breaking them off. These were really twisted!

I'll go into detail on how I re-stuff a E-Cap. Both of these caps are 4 sectioned caps. A while ago I won an auction that had like 25 E-Caps that were 4 sections with the sole purpose of using them as "donor" bases.

Here are the 2 caps and their donors.



I cut the originals as close to the base as I can with my band saw. I use a piece of 1/32 plywood as a shim to prop up the can because the base is larger in diameter. As I cut with the band saw, sometimes I'll rotate the cap some just to help keep the cut straight.



Here are the results of cutting the originals. All I'm interested in are the "cans". The bases are no good to me.
After removing the cardboard covers using my heat gun, I then cut the bases off the donor caps. This iime close but not so close to the base as with the originals. Here are the results:





Notice how much fuller the original cans are compared to the donors. Here is a picture of the original cans and the cleaned up donor bases. I clean up the bases using a brass brush and then drill a 5/32 hole in the middle. These holes were offset slightly to avoid drilling through the terminal symbols. I'll clean out the cans using a heat gun to remove the guts, and some steel wire brushes, acetone, paper towels, and Q-Tips to clean the cans.



The donor bases are about 1/8 inch taller than the originals. Not a problem on this chassis.



Next thing to do is make up some sleeves from 1 inch PVC pipe I got at Home Depot. I forgot the exact size but maybe it's 1 1/2 inch pipe. It is the thin walled stuff. The first thing I do is true up the end using my disc sander and 90 degree guide. When truing it up, I rotate the pipe about 1/2 to 3/4 turns.



I then mark the trued up end with an arrow. This end will be glued down against the base.



I then use my 1 inch wide ruler to make a mark 1 inch up from the trued end. I go all around the pipe.





I then cut off the pipe on the line just made. I then clean up the cut end with the disc sander. I then repeat the whole process for the other sleeve starting with truing up one end.
Once I have the sleeves cut out I then de-burr them using my hobby knife and #11 blade, and some 80 grit sandpaper.



I then use 15 minute epoxy and apply the epoxy on the trued up end being careful not to get any epoxy on the outside of the sleeve. Then the sleeve is inserted down onto the base. I then clean off any and all epoxy that has gotten onto the outside of the sleeve especially down near the base. Any epoxy here will prevent a good seam when the can is put into place.


Last edited by Crist Rigott; 11-23-2017 at 12:05 PM.
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  #64  
Old 11-09-2017, 11:41 PM
WISCOJIM WISCOJIM is offline
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Quote:
Originally Posted by Electronic M View Post
IIRC MacDonald had the engineers adapt a table model porthole chassis into the back seat of his limo so he could watch TV on the go....Some electronics mag of the day had a write up on it. I bet he let them do the article as a way to put out feelers to see if there would be a car-tv market.
Different MacDonald?

https://books.google.com/books?id=NN...r%20tv&f=false

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  #65  
Old 11-10-2017, 01:48 AM
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Quote:
Originally Posted by WISCOJIM View Post
That is the article I remember.
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  #66  
Old 11-10-2017, 08:14 AM
WISCOJIM WISCOJIM is offline
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Quote:
Originally Posted by Electronic M View Post
That is the article I remember.
I don't think this William M. MacDonald, Jr. had anything to do with Zenith Corp.

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  #67  
Old 11-10-2017, 11:01 AM
Crist Rigott Crist Rigott is offline
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OK, back on topic.
Here is what I did to make recapping a whole lot easier. I took 2 pieces of hardwood about 5/8 by 3/4 by 12 and bolted the to the side of the chassis. This allows a comfortable tilt while I'm working.

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  #68  
Old 11-11-2017, 09:14 AM
Crist Rigott Crist Rigott is offline
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OK, lets stuff C3. This E-Cap has 4 sections to it. For section A I'm using a 22uf 500V, section B is a 39uf 350V, section C is a 100uf 100V, and section D is a 82uf 100V cap. All are 105C Nichicons.

First thing I do is the see how well they fit into the PVC sleeve. Typically 4 will fit nicely. This gives me an idea on how to hot glue them together. I usually start with the 2 largest caps and glue them together with the negative terminals close to each other. Then the next largest and finally the smallest cap. I align the negative end of the caps to be equal. I then trim off the positive lead of each cap to about 1/4 inch in length. I then fold over the negative leads with my round nosed pliers toward the center and trim them off.



I use solid 22awg 600V wire for the new leads. I use black for the common and then loop it around the negative leads and solder them all together.



I then use the coil method to solder the new wires on each cap. For section A I use brown, section B is red, and so on.



I then fold over each wire toward the middle and then fold it again to have all the wires coming out together. Again, I use round nosed pliers for this. I then secure the wires together with some lacing cord to secure them.



I then insert the wires through the 5/32 hole I drilled into the base. I then place a mark on the wires where I want to strip them. I leave the common wire stripped a little longer like about 1/4 inch. I then trim off the excess wire length.



Next I put a large bead of hot glue on the lacing cord knot and inset the assembly into base. I then use hot glue around the inside of the sleeve to attach the caps to the sleeve.



I then terminate the wires on the base terminals. I typically will wrap the wires below the hole in the terminals. This leaves as much room for wires in the hole as possible. On this cap the half moon is section A, square is section B, triangle is section C, and no mark is section D. I'll terminate the common wire after the base is inserted into the chassis.





The new base is installed into the chassis, the common wire terminated and the soldered onto the chassis. Notice I went easy on the twisty things. The next guy will appreciate that. Though thinking about it, he'll never have to remove the base. Just unsolder the wires and pop out the caps!


Last edited by Crist Rigott; 11-11-2017 at 09:48 AM.
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  #69  
Old 11-11-2017, 12:24 PM
Crist Rigott Crist Rigott is offline
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Next up is C5. I used a 22uf 350V Nichicon cap. I installed a 3 position terminal strip and folded over the ground lug to keep it out of the way.





Then C6 got replaced with a Nichicon 10uf 350V cap. I used a 2 position terminal strip and soldered the ground lug to the chassis.




Last edited by Crist Rigott; 11-11-2017 at 12:30 PM.
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  #70  
Old 11-11-2017, 01:55 PM
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Beautiful job but one thought occurs to me. Capacitors can get warm from self heating due to internal ESR plus ripple current. Especially the main B+ filter caps. Sealing them up with hot glue and PVC isn't going to allow them to breathe much and may hasten their demise.
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  #71  
Old 11-11-2017, 04:31 PM
Crist Rigott Crist Rigott is offline
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Thanks Bob. Good thought. After I get it running and with the can off I'll do a temp measurement and report back. I just might need to be reminded. Then again with the can on might be a good idea. We'll see together how this method works out.
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  #72  
Old 11-11-2017, 06:09 PM
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This is why whenever I restuff cans I always make sure to go with 105 C rated caps rather than the 85 C rated ones , and haven't had any failures of my restuffs yet .
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  #73  
Old 11-11-2017, 06:33 PM
Crist Rigott Crist Rigott is offline
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This is why whenever I restuff cans I always make sure to go with 105 C rated caps rather than the 85 C rated ones , and haven't had any failures of my restuffs yet .
Yep!
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  #74  
Old 11-11-2017, 06:39 PM
Crist Rigott Crist Rigott is offline
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I did some chassis work this afternoon. I looked for a section that could complete and saw this section. R116 was a 2 part resistor of 200 ohms each rated at 3W. Also the Candohm resistor is 15K rated at 10W. It was open. Didn't really matter, it was going to get replaced anyway.
I replaced the 200 ohm 3W with 200 ohm 7W resistors and the Candohm was replaced with a 15K 50W chassis mount resistor. I used some heat sink compound between the resistor and chassis.



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  #75  
Old 11-12-2017, 04:55 PM
Crist Rigott Crist Rigott is offline
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When I recap a chassis, I usually replace the resistors, and mica caps too. I get my 1W resistors from Mouser and they only cost 4 cents each, so I change them out. Of the past chassis I've done I see that at least 50% of the resistors are out of tolerance, 25% are very close, and 25% are within tolerance.

I'll cover what I do on a terminal strip. Tube sockets are treated the same. The first thing I do is take several pictures of the terminal strip. Then I draw out the terminals and what is connected to them. I also add where the other end is terminated. I then double check my drawing.

I then cut off the components and leave about 1/4 long leads still attached to the terminals. Then I use my solder sucker and solder wick, I clean off the terminal and remove the cut off leads. Then if a wire/wires are attached to the terminal, I clean it up and put the wire as far down the terminal as possible. I trim the leads to wrap around the terminal but not long enough to go back over the hole in the terminal. This keeps the hole opened up for additional components. When the wire/wires are set on the terminal, I then solder them to the terminal using as little solder as possible. I do this to be sure that the wire/wires are soldered to the terminal because when components are added and with the wire/wires being down low, they might be missed when adding solder. Also this small amount of solder holds the wire in place.

I then try to add the components in a logical manner. Once the terminal is fully populated, I solder it and then clean off the flux with an acid brush cut down to about 1/4 to 3/8 inch and acetone.





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