Forums :: NEW! Web Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Nov Mon 29, 2021 7:10 pm


All times are UTC [ DST ]





Post New Topic Post Reply  [ 7 posts ] 
Author Message
 Post subject: RCA Victor R-50/ RAE-59 Woes
PostPosted: Sep Mon 20, 2021 3:07 am 
Member
User avatar

Joined: Apr Wed 01, 2015 1:20 am
Posts: 129
Location: Sedro Woolley, Washington USA
Been working on this one for a while. It's been a definite butt kicker. Last technician rely did a bodge job in the radio, bypassed stuff while keeping old componets in circuit, bypassing resistors that are blown up the same way. So I've spent a good hunk replacing all Caps with Panasonic PP and Nichicon Electrolytic. Wires replaced that were burnt. All resistors changed mostly because of many were burnt out or 50% plus OOT. New cord, all tubes tested on my Precision 660 all tested high, no shorts. Wiring checked,. Double checked and Triple Checked. Interstage transformer was replaced due to the Primary was open, and secondary was high resistive (1.2 meg). Replaced with a 124D Hammond. (As many said it will work). It had been changed once before as there was tape and solder on all the leads for the interstage in the can, and the tar potting was definitely not original.

Below in the pics I have pin by pin voltages on all the tubes. I do see one issue I can't seem to sort on one tune with very little voltages on the tube.

Radio powers up all tubes light up but there is zero Output, no static, no stations nothing.

Speaker passes test as I do have a very quiet hum in the speaker.

I took my SG8 and set it at 900 khz and tuned the radio back and forth and found a very very quiet signal at about 850 khz. Volume didn't control it, and SG8 was set at max output and volume on radio was set at max.

Finding out I could use the Radiola 80 as a alignment guide, I set the SG at 175 khz and injected into the grid of the first IF stage. I could just barely hear the signal. About a 1/4 of what I heard on 900 injecting into the antenna.

Adjusting 1st and second IF I gained maybe a few Db of signal adjusting 3rd IF nothing changed.

Setting the SG a 1400 khz and back to injecting onto the antenna adjusting the 4 padders no change. I did not mess with the 600 khz adjustment as the dial is so close to being on.

Interesting thing... On both 47 tubes if I tap on pin 3 that goes to the output of the interstage I get the same noise out of the speaker. Tapping on it with my Fluke Probe. If I use a pencil of anything else I get nothing.

Pics below of my work, and the voltages pin by pin. All voltages are from pin to chassis so that's why my filament voltages are halved. Going across the filament the voltages are on spec. Voltages are higher due to 117v wall output. I can redo the measurements with the transformer flipped to 110v and on the Variac set to 110 if needed.

Like I said. Nothing's getting hot, all resistors stay below 80F even after extended running.

I really hope I wasn't steered wrong on the Hammond 124D. Multiple people said they have used one to replace a failed interstage on many older RCAs.

And yes the jumpers are in correct position to run the R50 in standalone mode. I do not have the rest for the RAE59 components at this time.


Attachments:
PXL_20210920_013525229.jpg
PXL_20210920_013525229.jpg [ 3.75 MiB | Viewed 374 times ]
PXL_20210920_010017135.jpg
PXL_20210920_010017135.jpg [ 935.4 KiB | Viewed 374 times ]
PXL_20210920_010020460.jpg
PXL_20210920_010020460.jpg [ 903.8 KiB | Viewed 374 times ]

_________________
Success is the ability to go from one failure to the next without any loss of enthusiasm :D
Top
 Profile  
 
 Post subject: Re: RCA Victor R-50/ RAE-59 Woes
PostPosted: Sep Mon 20, 2021 2:57 pm 
Member

Joined: Jan Mon 16, 2012 4:15 pm
Posts: 8289
Location: Near Brandon, Iowa
When evaluating an installed replacement transformer, the only things that really matter are: (1) secondary voltages in operation; and (2) steady-state operating temperature. If the secondary voltages are all OK when the transformer is fully loaded, you can safely conclude that the transformer has enough current reserve to supply the radio without "voltage droop" which would indicate excessive current demand. The other parameter, steady-state operating temp, is a further indicator of whether or not the transformer has adequate "reserve" to source power; transformers that run excessively hot ("hot" being an imprecise term that should here be interpreted as "being near or above the specified range of temperature operation of the transformer").


Top
 Profile  
 
 Post subject: Re: RCA Victor R-50/ RAE-59 Woes
PostPosted: Sep Mon 20, 2021 3:07 pm 
Member
User avatar

Joined: Jan Tue 31, 2012 1:55 am
Posts: 18652
Location: Mountains of Mourne. Ireland.
Factory service literature attached below (23-pages).
from: https://worldradiohistory.com/RCA-Victor-Service.htm


Attachments:
Pages from RCA-Service-Data-1923-1932-A.pdf [1.23 MiB]
Downloaded 5 times
Pages from RCA-Victor-Service-Notes-1931-1932.pdf [820.04 KiB]
Downloaded 9 times
Top
 Profile  
 
 Post subject: Re: RCA Victor R-50/ RAE-59 Woes
PostPosted: Sep Tue 21, 2021 12:34 am 
Member
User avatar

Joined: Apr Wed 01, 2015 1:20 am
Posts: 129
Location: Sedro Woolley, Washington USA
Found L16 to be open, sadly I cannot find any specs for it. The reason why I didn't have any plate voltage on the second IF Tube.


Attachments:
PXL_20210920_230310590.jpg
PXL_20210920_230310590.jpg [ 2.97 MiB | Viewed 302 times ]
PXL_20210920_230109750.jpg
PXL_20210920_230109750.jpg [ 3.46 MiB | Viewed 302 times ]

_________________
Success is the ability to go from one failure to the next without any loss of enthusiasm :D
Top
 Profile  
 
 Post subject: Re: RCA Victor R-50/ RAE-59 Woes
PostPosted: Sep Tue 21, 2021 12:42 am 
Member
User avatar

Joined: Apr Wed 01, 2015 1:20 am
Posts: 129
Location: Sedro Woolley, Washington USA
Found the break about 10 turns in where they spliced 2 wires together to finish off the wind.

_________________
Success is the ability to go from one failure to the next without any loss of enthusiasm :D


Top
 Profile  
 
 Post subject: Re: RCA Victor R-50/ RAE-59 Woes
PostPosted: Sep Tue 21, 2021 3:59 am 
Member
User avatar

Joined: Apr Wed 01, 2015 1:20 am
Posts: 129
Location: Sedro Woolley, Washington USA
Coil fixed. Break was only about 10 turns into the coil. And oddly it was like a factory splice where it broke. I need up finding wires twisted together about a turn past the break. Checked ohms, had 87 ohms so I soldered it back into the circuit, and hit the switch to see proper voltages on the tube, and my volume and tone controls started working, and I had static!

Grabbed the SG8 still set on 175 khz, and boy was initial alignment away the heck off. Got a nice strong beat, flipped it to 1400 khz and dial was dead on to peak the 4 antenna padders and hit the lights to get a long lost of stations coming thru. Waited for 730 for the local 660 station to go into night mode, tuned up to just above the 1500 mark to hear the far distant station from Sacramento made a bit of a tweak to the padders on its own antenna and things are working great.

After 45 mins of run time 47 tubes sat happily at 215F and a the others were 140-160F all resistors and caps cool and unit is pulling just shy of 1 amp.

_________________
Success is the ability to go from one failure to the next without any loss of enthusiasm :D


Top
 Profile  
 
 Post subject: Re: RCA Victor R-50/ RAE-59 Woes
PostPosted: Sep Tue 21, 2021 2:36 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1180
Location: Bristol TN 37620
Good job, Dan.


Top
 Profile  
 
Post New Topic Post Reply  [ 7 posts ]  Moderators: Norm Leal, Marcc

All times are UTC [ DST ]


Who is online

Users browsing this forum: Google [Bot], lorenz200w, quaybee and 19 guests



Search for:
Jump to:  




































Privacy Policy :: Powered by phpBB