RCA Victor 9X-561 Radio

[selmafrog]

I have replaced almost all of the capacitors (I left two which looked like wire-wound resistors) on this, I think, 1952 RCA AM radio. Had to replace one dial lamp. Turns on, I get good sound - AM radio only. I have taken voltage readings and have a question about one pin on the 35Z5GT. That pin is pin 1, which I do not find any connections for on the schematic.
I am posting the photofact voltage values and those I took. If you need the schematic, I can post a pic of that.
In the attached text file, the first row of each tube is the voltages from the photofact. The second row is the voltages I got from the powered-on radio.
Thank you for your input.
Oh yeah, I will, pretty soon, either have to learn how to re-cone a speaker or purchase a replacement. With my old bent fingers, it is very easy to poke a hole in this fragile cone.

 

[wparks]

I took the liberty of converting the text to replace spaces with underlines, as AK has an annoying habit of stripping out extra spaces to save storage space, and converting the text to courier so all characters have the same spacing so the alignment works. Hopefully it still looks the same after this is posted.

The 35Z5GT pin 1 is a 'no connect'. I suspect there are other tubes in the lineup that are also blank (no pin) or have no-connect pins, so if you see a voltage at a pin that is not in the chart, it may be that pin is being used as a convenient connect point.



Yes- if you can post a readable picture of the schematic, or attach a .pdf when you ask for help it saves us from having to track one down to be able to help, but no worries, I found it in Beitman 1950 volume 10 page 124 and the world radio history museum.


Are you having any problems with the radio you need debug help with, or just that one pin question?


(==EDIT== Text removed, it looks bad because AK strips out <ALL> extraneously repeated characters, no matter how important)

 

[wparks]

Nope! it still looks like garbage. Thank You AK for stripping out all the extra characters!

Here it is as an image. (I will note taking up <slightly> more storage space than a few extra spaces . . .)

 

[wparks]

Curious if you have done the alignment on this radio? I was always so shocked at how much better the radio performance was once everything was aligned- you can lose so much signal and pick up so much noise if the IF cans are not peaked just right- and some of them can drift a great deal over the years.

 

[selmafrog]

No, I am not having problems. I waited over a week to get a 1409 dial lamp to replace one not working before I felt okay to power it on long enough to get the voltage readings and button it down. I just wanted someone else to give me his/her opinion before I put the chassis back in and then put the back plate on. I am really pleased with the sound. Now I want to find a really good tube amplifier to restore so I can compare that sound to my " for parts Kenwood KA-6004 amp". The sound from my parts amp, which has all the old caps, is more mellow than the one I just restored (which sounds kind of bright to me, so I may have to look into changing some of the caps I used. I was not very selective - just wanted to get it working).
Thank you for the input.

 

[selmafrog]

I thought I would have to do an alignment, but, so far I am satisfied with the way it is performing. Voltages are, I think, good; does not feel like excessive heat being produced anywhere; sound is clear - definitely no hum like in the '57 Gibson amp I finished a couple of months back.
Is there a reason I should attempt an alignment? That is something I have never done.

 

[wparks]

If you are going to work on more than just the one radio, it's a skill that will be very useful to pick up. There are lots of videos and guides on how to do it, so I won't go into details. If the radio is working and has enough sensitivity and performs to your satisfaction, and the indicated dial frequency matches pretty well with the actual station frequency, it probably is not necessary. In the dozens of radios I restored years ago, I recall that almost every set improved at least somewhat with an alignment, some few improved dramatically.

 

[selmafrog]

I thought I would have to align and then I tuned into WSB AM at Frequency 750.0. I checked my dial and it was just a hair above 75. I want to say it is okay.

 

[init4fun]

I thought I would have to do an alignment, but, so far I am satisfied with the way it is performing.

If you are satisfied with the way it's performing, I'd say "why fix what ain't broke"

And, if you want to learn how to align an old tube radio, first do a bunch of reading on the subject, acquire the needed equipment, then get a radio that your not satisfied with the performance of and let that be your "learning curve" set.

 

[selmafrog]

Let me ask this. When the radio is on, and I move my hand to the back of the radio and the volume increase is a good bit - will an alignment have any effect on this, or will this also happen after the alignment has been performed to the published method? I include this - I have never worn a wristwatch. This started back in my early teen years because when I wound a watch and set it to the correct time, a short time later it would either be way ahead of the current time, or it would be way behind the current time. This happened with more than one watch, and is the reason I never got use to wearing a wristwatch. I could carry a pocket watch on a chain, but not on my wrist. Could that be part of the cause of the increase in volume?

 

[wparks]

I think you will find that effect with just about any radio in almost any condition. We act as nice big conductive and capacitive bags of salty water, so when we move our hand around a radio it will usually cause some additional signal (or noise in some cases) to be coupled in.

This effect can be used to great benefit when using a passive resonant antenna booster- usually a big coil of wire with a tuning capacitor, that can be adjusted to have the resonant frequency of whatever station you desire- it resonates with the station and helps to re-transmit it to the radio. Easier and more selective than holding your hand there.