Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Antique phonographs

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 05-13-2017, 09:35 PM
bigaudioal's Avatar
bigaudioal bigaudioal is offline
Hello, I must be going
 
Join Date: Mar 2012
Location: Montgomery Village, MD
Posts: 594
RCA (model 6-EY-3A) 45 player

I recently grabbed a nice RCA 45 player, model 6-EY-3A. Recapped the amp and serviced the turntable. Motor and turntable work great but I do not have any audio. Replaced the cartridge and needle with a replacement from Gary at V-M Enthusiasts. Still zero audio. Started poking around and injected an audio signal into both sides of the primary of the audio output transformer and got good sound. So I know the transformer is still good. Tested and swapped both the AF amp tube and the audio output tube, no change. I then started testing voltages and noticed that I have 0 volts on the plate of the audio output tube (should be 120V). Also, I have 0 volts on the second grid of the audio output tube (should be 115V). I then noticed that I had 120 V on both sides of the selenium rectifier and 0 volts after the 47 ohm (some models use 22 ohm) resistor right after the selenium. I should have 130 V right after the selenium according to the schematic.

I want to replace the selenium and 47 ohm resistor right after it, but am having a few issues. I figured I would use a diode to replace the rectifier. I had two on hand. A 1N5408 and a 1N4007. Both of these produced no change in performance and I had 120 V going into the diode, but 0 volts coming out. I then replaced the resisitor with a newer 47 ohm one. I tried a 5 watter and a 10 watter, both wirewound ohmites. Both resistors overheated and turned red hot. Shut down before any damage to anything, as I was monitoring the resistor.

So what am I missing? What should I be using to replace this selenium and the dropping resistor after it? I did see a note that the resistor should be a "surge" type resistor. But no wattage is listed anywhere. Original 47 ohm is one of the white, rectangular long resistors. Says 47 ohm on it, but no wattage.

See below photos of full schematic, closeup of selenium and resistor (R9) section of schematic, then two more photos showing the specs of selenium and resistor. Note, I have the version with the 47 ohm resistor, not the 22 ohm one.

Any advice about what parts to replace this selenium and resistor with would be greatly appreciated.

Also, any advice on anything additionally that might cause 0 volts on pins 3 and 4 of the audio output tube where there should be 120 volts and 115 volts would be much appreciated.

Thanks everyone.
Attached Images
File Type: jpg Full Schematic.jpg (60.0 KB, 29 views)
File Type: jpg Selenium and Resistor.jpg (49.1 KB, 24 views)
File Type: jpg Selenium.jpg (76.4 KB, 18 views)
File Type: jpg R9.jpg (74.3 KB, 21 views)
__________________
-Al
Reply With Quote
  #2  
Old 05-13-2017, 11:27 PM
Electronic M's Avatar
Electronic M Electronic M is offline
M is for Memory
 
Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
Posts: 8,999
If the replacement is physically the same size or bigger than the original then I'd be looking for a short or near sort on that B+ line.
__________________
Tom C.

What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4

Reading between the scan lines since the mid 2000's.
Reply With Quote
  #3  
Old 05-13-2017, 11:37 PM
bigaudioal's Avatar
bigaudioal bigaudioal is offline
Hello, I must be going
 
Join Date: Mar 2012
Location: Montgomery Village, MD
Posts: 594
Quote:
Originally Posted by Electronic M View Post
If the replacement is physically the same size or bigger than the original then I'd be looking for a short or near sort on that B+ line.
I just did this testing. I disconnected red wire going to 80 lytic and looked for shorts to chassis ground. No shorts. I also tested to see if B- was shorted too. No shorts there either. Cannot find any shorts at all. No shorts in the audio output transformer either.

One thing I noticed in the schematics, on the selenium, the anode appears to be on the left and cathode on the right. I thought anode is usually associated with the + symbol and cathode with the - symbol. Both the RCA schematics and SAMS seems to have anode as - and cathode as +. Bit confusing.
__________________
-Al
Reply With Quote
  #4  
Old 05-14-2017, 05:59 PM
bigaudioal's Avatar
bigaudioal bigaudioal is offline
Hello, I must be going
 
Join Date: Mar 2012
Location: Montgomery Village, MD
Posts: 594
I got it now!!!! Thanks for the advice everyone. Voltages are within a few volts on all measurements. Turns out there were two issues. Diode installed backwards and then original 47 ohm resistor was open. Once I got that figured out and bumped the resistor up to a 100 ohm/5 watter (to be safe), all is running great and within specs.

YouTube video for your enjoyment. Thx!

https://youtu.be/fScvt2-tFpg
__________________
-Al
Reply With Quote
  #5  
Old 07-20-2017, 10:38 AM
Bill Cahill's Avatar
Bill Cahill Bill Cahill is offline
Super Moderator
 
Join Date: Mar 2005
Location: St. Petersburg, Fl.
Posts: 1,269
Post

Actually, the arrow is the anode, and, the straight line is the cathode on the silicons, at least.. You did very well, and, sounds as if you did a top notch job.
__________________
"Tubes are those little glass things that light up orange unless there is a short.. Then they light up all pretty colors..."
Please join my forum.
http://tuberadio.heavenforum.com/ind...c8c9de9e96fd7d
Reply With Quote
Audiokarma
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:29 PM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
ęCopyright 2012 VideoKarma.org, All rights reserved.