Midwest set nearing completion

[ohohyodafarted]

2/2/2008 PROJECT COMPLETED, see new photos below of operational set

Hi Gang,

It has been a long road, but after several months of persistant work the chassis on the Midwest 16" set is completed. The walnut veneered cabinet is presently about 1/2 refinished and will be about 2 or 3 more weeks before the refinishing is done.

So I thought I would start this thread and show what has been done so far.

To bring you all up to speed, I will outline some of the restoration issues on the chassis:

I received the set about 1 year ago from an ebay auction. I picked the set up in the Cincinatti area. The previous owner was going to restore the set but found that the project was to advanced for his level so decided to sell it, When I got the set home, I discovered the 16ap4 had a broken tipoff and was no good as a result. So first thing I did was obtain a like new crt for the project.

Next I obtained a schematic courtesy of Steve Kissinger. It is a Ryders print and there are no photographs of the underside of the chassis like you have in a Sams Photofact folder.

I removed all the components from the cabinet and when I turned the chassis over I was shocked to discover that MANY capacitors had been removed from the chassis. As I probed deeper into the wiring it bacame apparent that somebody with very poor electronic repair qualifications had been trying to maintain and repair this chassis. Lots of cobbled together resistors, and several circuit mods that were not appropriate.

The most difficult thing about this restoration was the fact that I had to virtually trace out every wire and component point to point from reading the schematic alone, with no photos to go on. By working one tube at a time I was able to find many components that were missing and several wiring mistakes or mods that had been performed.

Among the things I found were:
- Chassis was completely striped of its 31 tubes
- 2 droping resistors in the power supply open
- 8 capacitors that were completely missing from the previous owners restoration attempt
- More than 20 resistors either burned or way out of tollerance
- Several wires missing
- 2 wirewound controls open
- A leaky 20KV doorknob cap

More than 30 caps were replaced, 5 cans were restuffed and 31 tubes were required to repopulate the chassis.

One of the wirewound pots (vertical centering) was open. It was a 15 ohm 2 watt wirewound with a center tap at 7.5 ohms. (pure unobtanium). I was able to obtain a 4 watt 15ohm wirewound pot. I carefully disasembled the control and removed the wirewound element from the bakelite housing. I then used a Dremel tool to make a small inscision in the bakelite housing to allow me to insert a 1/8" wide by 1" long piece of brass shim stock, at the 7.5ohm midpoint of the element, between the resistance element and the side of the bakelite housing. I reassembled the unit and Viola....I had a 15ohm pot with a 7.5 ohm center tap.

After I was pretty sure that I had the chassis rewired and recaped as well as I could, I decided to fire it up. I was relieved to find that I had High Voltage right off the bat. After some fiddling and tube swaping I was able to get a raster, and with some more fiddling I got video and it was in sync too. I was missing a tube and after it arrived, I poped it in and then the audio came alive, along with the AM and FM radio sections.

I removed the front panel and striped off the old lacquer coating and used a household copper cleaner to restore the luster to the copper plated panel. I then recoated the panel with 2 coats of clear acrylic lacquer to pevent tarnishing.

There are 3 back lit windows with lables for the knob functions. The labels are made of celuloid and are silk screened and painted on the rear with a translucent coat of yellow paint. The label for the Horizontal/Vertical knob set was completely missing. I had to come up with a reproduction.

Here is what I did:
From one of those infernal PVC bubble packages that everyone hates opening I scavenged a peice of clear PVC plastic about .020 thick and about 2 inches square. I used a graphic arts program to lay out the words to be printed and fliped the artwork so it would print a mirror image on my printer. I mounted the PVC plastic with double stick tape to a 8.5 by 11 inch piece of copy paper so I could feed it through my laser printer. The printer then printed the lettering on the back side of the clear PVC. So that when you look at the printed plastic from the front side, the lettering on the back side reads properly. I then spray painted a thin coat of yellow paint on the rear of the plastic covering the printed black lettering. When viewed from the front, you see black letters on a yellow background printed on the back side of clear plastic. I fastened the plastic label to the back side of the front panel using 4 minute setting epoxy. As you can see from the photo attached, the little yellow window on the right is a pretty good facsimile of the other two.

So now I have the rest of the cabinet to finish. When that is completed and I have the set reassembled I will come back with photos of the completed project. Until then, at least you have some photos of the set in the condition it was received in, and photos of the completed chassis.

http://www.audiokarma.org/forums/att...5&d=1174972977


Enjoy!

Bob

[Eric H]

Wow, that looks great!
Don't you just love the really tough ones?

When can we see pics of the finished set?

[Dan Starnes]

I am very impressed,, very nice job!
Dan

[Sandy G]

Woah ! Excellent...Can't wait to see the finished product !!

[Tube TV]

Nice job ! , Im looking forward to seeing more pics when it's all done .

[Snade]

Only one thing to say.

Wow.

[zenithfan1]

{Now picking jaw up off of floor!} WOW!!!

[ohohyodafarted]

Project Completed 2/2/2008

[zenithfan1]

Absolutely beautiful job!!!! Amazing picture on that set. Looks better than new!!!

[John Folsom]

Bob, That really did come out nicely. Great refinishing job. I like the styling on that set. That tall thin "grandfather clock" look is really eye catching.

[kbmuri]

Wow!

[jpdylon]

Bob, that is some really incredible work! The restoration work and cabinet refinish both look absolutely fantastic.

The pictures speak for themselves, well done.

[Dave A]

It might be time for a "Restoration of the Year" award.

Dave A

[ohohyodafarted]

Naaa... I don't want no freeking award....

just find me the chanel selector knobs and a usable bulb for a ct100

Bob