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RCA Stratoworld 3BX571
#1

http://www.radioatticarchives.com/radio.htm?radio=8951

The RCA Stratoworld was RCA's answer to the Zenith T/O. This one on the bench is from 1953. Fixing it for friend it came in unmolested abt 5 or 6yrs ago. I took a quick look at it then and after some troubleshooting found what I thought was a bad 1st IF transformer. Fast forward to now. Got it up on the dining room table started to sort it out. Plugged it in and gave it a go. Had audio hiss with some pops and level changes. So went through and replaced the caps in the audio stages. Helped a little and cleaned the controls too.
Applied a 455kc signal to the grid of the IF amp tube and received a signal from the spkr. Did the same to the plate of the mixer tube (1L6) read very expensive toob) All was well. Tried the input grid of the 1L6 and got nothing. Hmmmm. Should be able the pass a signal. Check voltage and look pretty good. Unfortunity my old wartime I-177 tube tester won't test a lot of these modern 7 pin toobs.
Did some research and found that you can use a 1R5 (read cheap battery toob use in just every portable made in the 50's and 60's that don't have a 1L6) with a modification. (remove pin 5 from the tube). Dug a 1R5 and off came pin 5. Carefully inserted in to the set and gave it a try. Well the 1L6 was bad the 1R5 caused it to spring to life.
So now it's working still is albeit noisy but still several bumblebee cap that need to go. Friends job is to come up with a good 1L6!
Ordered a bunch of mylar caps, resistors, and a few micas. So I'm waiting for them to show up to finish this and that Philco 42-854

Terry
#2

Very nifty, a radio worth saving, bet it will be hot for what is left on SW, WBCQ!

PAul

Tubetalk1
#3

Timmy Smith would be proud!!!

Terry
#4

(06-14-2016, 06:31 PM)Radioroslyn Wrote:  http://www.radioatticarchives.com/radio.htm?radio=8951

The RCA Stratoworld was RCA's answer to the Zenith T/O. 
Took them a while.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#5

Terry
So all you did was removed pin 5 nothing else 

Some day, and that day may never come, I will call upon you to do a service for me. But until that day, accept this justice as a gift
mafiamen2
#6

Yeah just pin 5 but it's not a perfect match as the interelectrode capacitance is a bit different. In some circuits it doesn't like to work above 10 or 12mc. But is good for testing on the lower bands.

Terry
#7

Hit a big bump in the road!! The dial on this set is part of the cabinet so with the chassis out you can't tell what frequency  your on. I noticed in passing that it seemed to tune backwards (dial pointer is to the left tuning cap should be closed and open when the pointer is to the right) I didn't give it much thought as I was thinking it was just my imagination running a way with me.
Last nite I was giving the SW bands a try to hear if they where working and noticed that CHU came in load and clear and I tuned a bit higher in frequency to hear some activity on the 80mtr ham band but wait the dial pointer is moving to the left (should be moving to the right!!!!).
Now most are not particularly difficult BUT this one has 4 strings to do the tuning and move the pointer. The RCA service info is rather vague and hard to figure out. I think someone in it's past tried to restring it and wound the string around the tuning cap hub backwards. So much for unmolested!!!!
Are Phorum Phiend Bill (Sparkbench or Bill M) has on his site a simplified diagram on how to restring this thing. So I think I'll give it a go. Got to get some cord.
http://www.videokarma.org/showthread.php?t=263547
This guy always gives me JUNK to work on!!!!

Terry
#8

Good luck with that dial cord!

Years ago in the age of B.I. (before Internet) and before I owned my own silver fish farm (Rider Manuals) I had a Silvertone that drove me nuts.  When I finally thought I had it re-strung correctly it would move backwards.  Finally my Rider Manual prints arrived by snail mail and thankfully it had a diagram on how to string the dial.  It was a very strange affair that I doubt I would have ever figured out on my own.

John KK4ZLF
Lexington, KY
"illegitimis non carborundum"




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