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A few months ago, I bought Philco 90 chassis from one of our friends at ARF. This is the less common late version, with the push-pull 47 output. I haven't done a complete radio restoration in more than a year. After watching Ron's restorations and a couple of others, I decided it's time to do this one. About the time I bought the chassis, I had a fellow order a 90 cabinet so, I went ahead and made two at the same time, knowing I would need one. Also, the large tube shield was missing. I was able to find a 91 tube shield on eBay. The only thing I don't have is the correct speaker.
[Image: https://live.staticflickr.com/65535/4816...c04b_k.jpg] Philco 90 Chassis by Steve Davis, on Flickr
[Image: https://live.staticflickr.com/65535/4816...81df_k.jpg] Philco 90 Chassis by Steve Davis, on Flickr
M R Radios C M Tubes
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The chassis has quite a few rusted spots that I have sanded out. I removed the tuning condenser and masked aluminum cans and tube sockets. I bought a couple of cans of spray paint, hoping to find a close match to the original color.
[Image: https://live.staticflickr.com/65535/4916...6327_k.jpg] 100_0039 by Steve Davis, on Flickr
The Ultra Matte Slate turned out to be a little bit dark.
[Image: https://live.staticflickr.com/65535/4916...961b_k.jpg] 100_0021 by Steve Davis, on Flickr
So, I tried Satin Granite.
[Image: https://live.staticflickr.com/65535/4916...5707_k.jpg] 100_0038 by Steve Davis, on Flickr
It turned out too light.
[Image: https://live.staticflickr.com/65535/4916...23a9_k.jpg] 100_0029 by Steve Davis, on Flickr
I decided to mix the two. I sprayed the paint in to a couple of mixing cups then mixed them and used my spray gun to apply. After a little trial and error, I came pretty close. The tube shield is the original finish.
[Image: https://live.staticflickr.com/65535/4916...8779_k.jpg] 100_0031 by Steve Davis, on Flickr
Steve
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That looks good Steve. I've had the same problem of trying to find a paint that is close to original chassis color in a spray can.
Keep the restoration updates coming.
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Ron Ramirez
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I'm watching carefully too! I've had to paint a couple of chassis but have had a hard time deciding what the original color was. Heavily oxidized cadmium is different than fresh cadmium (I've cadmium plated a few aircraft parts.) Chassis areas that have been covered with transformer mounting tabs look different than the exposed areas (much brighter.) I've used a brighter aluminum paint which is, no doubt, much lighter, brighter than original. I'm anxious to see how yours turns out!!
(This post was last modified: 12-03-2019, 10:28 PM by rfeenstra.)
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The early Philco chassis such as the 90 were not cadmium plated. I'm not sure what they used, it looks like some thin wash coat of some kind. Slightly later Philcos had cadmium plated chassis.
Steve
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oh boo you didn't paint it hot pink ha ha.
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Jake, go ahead and send me yours, I'll paint it hot pink for you 
Steve
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All i used is gojo and mothers mag polish on mine lots of black and nicotine paste came off but my old 50A smelled like 70+ of cigar use. cleaned up pretty well but i was fortunate there was no rust.
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I removed the end bells from the power transformer, cleaned and painted them. I painted the core while still on the chassis. I masked the windings and placed cardboard under it to protect the chassis.
[Image: https://live.staticflickr.com/65535/4916...e1ec_k.jpg] 100_0041 by Steve Davis, on Flickr
[Image: https://live.staticflickr.com/65535/4916...a188_k.jpg] 100_0045 by Steve Davis, on Flickr
[Image: https://live.staticflickr.com/65535/4916...d8a7_k.jpg] 100_0058 by Steve Davis, on Flickr
Steve
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I like your chassis helper though it does look heavy.
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I'm ready to start restuffing condenser blocks. I have a new set of "dogbone" resistors that I will be installing at the same time.
[Image: https://live.staticflickr.com/65535/4916...ebf6_k.jpg] Philco 90 Restoration by Steve Davis, on Flickr
When I look at the bottom of the chassis, I can see a few problems. The most noticeable is the end section of the B-C resistor is burned. This section provides the bias for the 47 tubes. It reads 195 ohms, it should be 205. That makes me wonder if there one or two turns shorted. I may cut that section out and replace it with a separate resistor.
[Image: https://live.staticflickr.com/65535/4916...7dbf_k.jpg] Philco 90 Restoration by Steve Davis, on Flickr
Another thing is, someone in the past, added an extra capacitor that makes no sense. Originally there was a .25 uf located in a metal can with 3 other sections that by passes a 25K resistor going to the 27 detector amp. This lead to the .25 uf was clipped and the .01 cap was connected in series with the .25 uf. This looks to have been done many years ago.
[Image: https://live.staticflickr.com/65535/4917...9531_k.jpg] Philco 90 Restoration by Steve Davis, on Flickr
Steve
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