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Zenith 6D029
#1

Next project is a Zenith 6D029 that I picked up at Kutztown from phorum member Preston Smith.  It looked nice, had a nice back, wasn’t too pricey and Preston said it worked…sold.

[Image: https://www.dropbox.com/s/9vads5qljc492k....jpg?raw=1]

[Image: https://www.dropbox.com/s/tgtlt1ubz6f55e....jpg?raw=1]

[Image: https://www.dropbox.com/s/5ye4ieep97ycxo....jpg?raw=1]

[Image: https://www.dropbox.com/s/ck8ffx9t4itk88....jpg?raw=1]

Just doing some cleaning.  That black spacer around the grill cloth and dial cover is very fragile (don’t ask) and I’m going to have to find something to make a replacement.  I think it just serves as a spacer between the chassis and the cabinet.  Mark Palmquist had a replacement plastic dial cover and since I was at Ktown and he was at Ktown there was no shipping cost.   Icon_biggrin

[Image: https://www.dropbox.com/s/aeo77s1n5chqur....jpg?raw=1]

The dial string looked a little funky and was fraying.  The vertical dial string loop (on the right) on the radio was actually crossing itself just above the bottom pulley wheel and after I got the front dial off I could see there was not spring in the large pulley wheel.  It has obviously been restrung at some time in the past.  I decided to restring it and after a couple more turns the dial cord broke anyway, so there was no turning back.  I found a spring in my junk box that I think will do OK.  Here’s the restrung section with a dab of glue on the knot still drying.  

[Image: https://www.dropbox.com/s/4ndsgj6gi6w491....jpg?raw=1]

I’ll restring the horizontal dial string as well but that will have to wait until I put the dial back on and I won’t be doing that until after I finish recapping.  That makes it less likely I’ll damage the cardboard dial face and pointer and gives me some time to see if my spring and restring will hold.
Next, on to the recap…should be pretty straight forward except for getting to the electrolytic can leads which are buried under the terminal strip and several other components in the upper left corner of the photo.  

[Image: https://www.dropbox.com/s/7f7ysrq2no8pzb....jpg?raw=1]
#2

Broadcast band only I am guessing? Unique look to that set, Chitowns best,

Paul 

Tubetalk1
#3

Yes it only has broadcast band. I have the pre-war (1942) boomerang zenith 6D2615 also. Maybe I need to start an "everything boomerang" collection.... Icon_lol
#4

I decided to take on the hardest part first, the electrolytic.  It is buried deep under the terminal strip, a cap and a resistor.  I drilled out the rivet holding the terminal strip, disconnected a couple of wires and was able to pull it back out of the way.

[Image: https://www.dropbox.com/s/gv3won8nurs88p....jpg?raw=1]

It was still a tight fit and after trying to unsoldered the connection on the ecap lugs I decided it would be easier to cut them and then rewire when the ecap goes back in.  Zenith used the crappy rubber wire in this set so I'll be doing more rewiring than I had thought.  Fortunately only one of the twist lugs on the ecap was used as a B- connector so I was able to get most of the solder off it, untwist the 3 lugs and drop the ecap out.  Whew...

[Image: https://www.dropbox.com/s/u83liag0sctyun....jpg?raw=1]

I had decided I needed to pull and stuff the can since there really is no room under the chassis for a 40, 20 and 20 uF caps.
#5

Hi Bob,
If there is enough room on the top of the chassis I'll heat the cardboard tube and remove it, break out the Dremel w/a cut off wheel cut around the base abt 1/2 from the bottom. Clean out all the innards, drill sm holes next to each terminal to solder leads from the new cap. Mount new caps inside and slip the cardboard tube back over the top.

If there isn't enough room then I cut the terminals off the old cap and remove it. Find a donor cap w/the same # of connections out in the shed (have a few nos cans around) Cut it open gut it and put new caps inside. Drop it in where the old one was.

The plus to doing it this way is that you don't disturb the rubber wiring much which can be an advantage.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#6

Thanks Terry. I did think about doing it that way (cut the can from the top) but I had to take the terminal strip off anyway to get at a cap buried under it. Besides, I have to fumble around a bit and break a few things before it feels like I'm really working on it Icon_lol
#7

I've been able to get the recapping finished.  The ecap went back in without too much trouble.  With the smaller modern caps there was more room.  Several of the resistors were also replaced and a 1/2 amp fuse added.  
[Image: https://www.dropbox.com/s/lh4j76lymhx3cc....jpg?raw=1]
[Image: https://www.dropbox.com/s/vzzj4o1hmaip9w....jpg?raw=1]
[Image: https://www.dropbox.com/s/aqisas8aihk86l....jpg?raw=1]

I haven't aligned it yet but it is playing OK (it was playing before I recapped it so I didn't do any damage!).  

I do have a question for Terry or others who actually have an understanding of the way these circuits work.  
Here's a link to the entire schematic.
Below is a cut out of the schematic (left) and then the "as actually wired" (actual wiring in RED on the right)
The 0.0005 uF cap is connected to the plate of the 12SQ7 on one end but the other end is different than the schematic.  The radio is playing.  So do you think this is a schematic error or a mis-wired radio?  Or maybe it doesn't matter??  


[Image: https://www.dropbox.com/s/okrzcj80uzqgmr....jpg?raw=1]             [Image: https://www.dropbox.com/s/3ihd27q0ggwjx2....jpg?raw=1]
#8

At 500mmf it isn't going do much. It's either there to decouple a small amount signal from the plate of the 12SQ7 or to add some negative feedback between the two audio stages. This would increase the bass response of the amp stage. If you happen to have a small value cap laying around connect it in parallel with that 500mmf and hear what happens. Either it will cut some of the high frequency in the audio or get a little boost to the lows. Happy experimenting!!!
You know I'm a hacker at this!!!!
ps Good Job!

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#9

Darn...I was finishing up the cabinet and got all excited about putting it all back together and then after I finished I re-read this thread and realized I had not done the experimenting that Terry suggested....maybe if i pull it apart again sometime in the future.  

Anyway...I don't think I had posted this picture of the bottom of the set that shows the cabinet was made in Wisconsin by Jack Miller cabinet maker "for those that Demand the Finest"!  Kind of interesting.  

[Image: https://www.dropbox.com/s/572ofbcndcr45f....jpg?raw=1]

and here's the finished product ready to find a place somewhere in the house... originally (see the first post) the sides were brown but with the black knobs and black dial I thought black sides would look sharper....besides...its not like its a Philco...  Icon_lol

[Image: https://www.dropbox.com/s/9tms19tpb62sy3....jpg?raw=1]
#10

Holy crapoli!
That was fast my friend... I spent so much time with rubber wiring on my 525 and 629 I could not get the cabinet done for 3 weeks, lol...

Very pretty Bob...

My only criticism... It is not a Philco Icon_lol

Me

Times I have been electrocuted in 2021
As of 1/01/2021
AC: 4 DC: 1
Last year: 6
#11

Very,Very ,,NICE,,,beautiful workmanship,,Cheers
#12

  Very nice job. Icon_clap
#13

Nice when they work out so good, enjoy.

Muy excellente.

Pablo

Tubetalk1




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