Hi, I am a newbie in the wonderful world of tube technology.
I picked up a beautiful RCA Victor Stereo console at a thrift store for a mere $40. I am excited about it because it is my first tube stereo, it has FM, and to my surprise it can pick up shortwave with a apropriate antenna. I like the glowing blue magic eye too.
It was dead at the store for some reason, no lights no nothing.
So they chopped it down from $80 to $39. When I got it home, I took the back off and looked in to see all kinds of neat architecture of probably the 40's or 50's. I crossed my fingers and plugged it in, after a few secinds; the tubes glowed and the magic eye came on, and the dial lit up via two lightbulbs behind it.
Well I tuned in to an FM station, and followed the magic eye.
Rich deep sound came out of the left channel, but not the left.
I played with the ballance and if I turned it to the extreme left I could get weak sound on the left speaker.
I went into the unit and dissconected the unamplified stereo signal from the tuner/radio chasis, and fed it dorectly into some seperate speakers. I cranked the volume to the MAX and plugged the radio in. I got weak sound on BOTH channels, so there is left and right un amplified sound going INTO the Amplifier chassis.
There are two output transformers for each channel, I pray that the one for the left is not fried. There is a seperate tube for each channel so I switched them to see if it was a bad tube and no there wasn't a difference.
I only know basic electronics, and only basic understanding of the use of a multimeter. The machine is a big beautiful
RCA Victor with a turntable, FM/AM stereo speakers with bas and tweeters. Oh and I tested both speakers by touching a double "A" battery to the leads, they are both fine.
I am dying to get the old girl sounding good again. Its my first radio with tube goodnes. Thanks
I picked up a beautiful RCA Victor Stereo console at a thrift store for a mere $40. I am excited about it because it is my first tube stereo, it has FM, and to my surprise it can pick up shortwave with a apropriate antenna. I like the glowing blue magic eye too.
It was dead at the store for some reason, no lights no nothing.
So they chopped it down from $80 to $39. When I got it home, I took the back off and looked in to see all kinds of neat architecture of probably the 40's or 50's. I crossed my fingers and plugged it in, after a few secinds; the tubes glowed and the magic eye came on, and the dial lit up via two lightbulbs behind it.
Well I tuned in to an FM station, and followed the magic eye.
Rich deep sound came out of the left channel, but not the left.
I played with the ballance and if I turned it to the extreme left I could get weak sound on the left speaker.
I went into the unit and dissconected the unamplified stereo signal from the tuner/radio chasis, and fed it dorectly into some seperate speakers. I cranked the volume to the MAX and plugged the radio in. I got weak sound on BOTH channels, so there is left and right un amplified sound going INTO the Amplifier chassis.
There are two output transformers for each channel, I pray that the one for the left is not fried. There is a seperate tube for each channel so I switched them to see if it was a bad tube and no there wasn't a difference.
I only know basic electronics, and only basic understanding of the use of a multimeter. The machine is a big beautiful
RCA Victor with a turntable, FM/AM stereo speakers with bas and tweeters. Oh and I tested both speakers by touching a double "A" battery to the leads, they are both fine.
I am dying to get the old girl sounding good again. Its my first radio with tube goodnes. Thanks
...."I went into the unit and dissconected the unamplified stereo signal from the tuner/radio chasis, and fed it dorectly into some seperate speakers. I cranked the volume to the MAX and plugged the radio in. I got weak sound on BOTH channels, so there is left and right un amplified sound going INTO the Amplifier chassis.'....
Maybe the problem is in FM stereo decoder....?
Try to change left and right output of stereo decoder.
Maybe the problem is in FM stereo decoder....?
Try to change left and right output of stereo decoder.
azazello said:
From the description it does not sound like the tuner is the problem, but you need to proceed cautiously. First off you should never plug old tube gear into the wall without a thorough check out first, and the power supply caps should be replaced or reformed gradually - not brutally as when you plugged this thing in. (You are lucky no electrolytic exploded which is not an unusual outcome for this sort of mistake.)
That said you have identified that the tuner/radio chassis is working correctly for the moment and the problem resides in the amplifier section. It could be a bad tube, socket, open/badly drifted resistor or even a coupling capacitor. The OPT is least likely unless it got disconnected at some point in the past and was playing loudly at the time in which case internal arcing could result in a short in the primary.
You will need to find someone local who can perhaps guide you as you learn to rebuild the electronics in this console. Get some books on basic trouble shooting technique, tube era books so much the better. Morgan Jones has written an excellent book on hifi tube amplifier design aimed at people of all knowledge levels - "Valve Amplifiers" and I would get a copy right away if you do not already have it. You can get it on line at Old Colony Books (AudioXpress) or Amazon.
FM stereo arrived in 1961 so this unit is certainly no older than that.
You are very lucky you did not let out a lot of magic smoke when you plugged the thing in the first time.
---Civic..
Did you read the section in tubes titled "General safety....high voltages"??? Be very careful poking around on the inside of your pride & joy................she can & will bite you if your not careful.
We don't want to hear any electrocution stories from you on down the line!
________________________________________Rick.........
Did you read the section in tubes titled "General safety....high voltages"??? Be very careful poking around on the inside of your pride & joy................she can & will bite you if your not careful.
We don't want to hear any electrocution stories from you on down the line!
________________________________________Rick.........
Okay, I just tried that, and no there is no difference.
Could a bad capacitor cause a channel to be dead?
I notice that there is a seperate capacitor atached to the socket of each channel. I am narrowing it down to an issue in the sound amplifier section, because I have found that the tuner section is putiong out proper L/R unamplified sound on both channels, so I think the issue is in the amp. I pray that it is not a bad transformer, there is a big transformer per channel one for left and right. But I think those are very expensive to replace.
I hope it is just a matter of a bad cap. Can a bad cap cause a channel to be bad?
Could a bad capacitor cause a channel to be dead?
I notice that there is a seperate capacitor atached to the socket of each channel. I am narrowing it down to an issue in the sound amplifier section, because I have found that the tuner section is putiong out proper L/R unamplified sound on both channels, so I think the issue is in the amp. I pray that it is not a bad transformer, there is a big transformer per channel one for left and right. But I think those are very expensive to replace.
I hope it is just a matter of a bad cap. Can a bad cap cause a channel to be bad?
Thanks for the warning about safety! I am learning more and more as I creep along. I'm enjoying playing with this stuff.
Actully, I am glad the thing wasn't perfect to begin with, it is fun to figure it out and have the fun of making it work again and learn along the way. I never touch anything unless I unplug the cord. I read about the possibility of something letting go with a bang on power up. For all I know, this old girl has been sitting in a must damp basement for ten years. Everything looked ok, but I understand the risk.
Actully, I am glad the thing wasn't perfect to begin with, it is fun to figure it out and have the fun of making it work again and learn along the way. I never touch anything unless I unplug the cord. I read about the possibility of something letting go with a bang on power up. For all I know, this old girl has been sitting in a must damp basement for ten years. Everything looked ok, but I understand the risk.
kevinkr said:
I see only two (electrolydic?) capacitors on the amplifier stage.
One is atached to the sperate output tubes, "left" and "right".
I did an ohm test on each of the capacitors. They are the exact same types with the same values. But the reading on the meter was different on both capacitors. I don't understand.
At anyrate I hear it is standard practice to replace all the caps in one shot even if they are good, they will probably fail soon.
You could also do a few other basic things, like unplugging the tubes and re-installing them to get better contact on the pins if the unit has been idle for decades (with it powered down, of course), and checking to see if all the tubes are glowing with the unit powered up, that will eliminate heater/filament issues. You can also swap tubes from one channel to the other one at a time to see if the problem is tube related.
As mentioned, it'll probably be a good idea to change the caps at some point.
Another good beginner book is Bruce Rosenblit's Beginner's guide to tube audio design.
What tubes are in the console?
As mentioned, it'll probably be a good idea to change the caps at some point.
Another good beginner book is Bruce Rosenblit's Beginner's guide to tube audio design.
What tubes are in the console?
How exactly can a bad capacitor like where I said it was disable one side (channel) of my radio?
I hope it is not a bad output transformer, I hear they are very expensive and hard to find too. But I also ask; if it were an open connection in the left channel tranny, how can I hear sound at all even weak sound though the left channel if I turn my ballance to the left and crank the volume up?
I hope it is not a bad output transformer, I hear they are very expensive and hard to find too. But I also ask; if it were an open connection in the left channel tranny, how can I hear sound at all even weak sound though the left channel if I turn my ballance to the left and crank the volume up?
CivicProtection said:
The cap could be directly in the signal path - and if it fails open you won't have a connection for that channel. It could also be a cathode bypass cap which could affect gain.
CivicProtection said:
I think others have said that it's probably not the output transformers. If you insist on trying something, I'd swap the 6BQ5's and see if the low volume changes channels. But personally I'd change out all the caps, check all of the resistors, and replace or test all of the tubes.
G said:
There was a sticker on the back of the cabinet that had the model number on it, but half of it is gone. I googled what remained of the number and coul;dn't find jack on my RCA Victor.
Another sticker on the back says: The Debonaire.
I looked on some antique radio sites andalot of them were badly designed with cryptic infoemation stored haphazaredly.
I don't even know how old this thing is! It is all tubes, solid wood and plywood veneer. Has AM/FM and shortwave 1 and 2.
A blue magic "slit shaped" eye. and a record player.
And I did an ohm check and the chasis is probably not live.
The chasis, both of them are made of thick carbon steel.
The dial on the front is a sheet of glass.
I took my side cutters and cut out the cap that is atached to the tube for the left dead channel, to bring to the parts store. out of curiosity, I fired it up and I heard dead silance in the left channel, nothing even when I turned up the volume and cranked the balance to the extreme left. Before I could hear fain sound. So I am confident that if I change the caps in that amp section everything will be good.
I took the unamplified sound coming from the tuner section and hooked it to my modern amplifier, and turned it all on. The sound sounds good. so the tuner is OK.
I took the unamplified sound coming from the tuner section and hooked it to my modern amplifier, and turned it all on. The sound sounds good. so the tuner is OK.
Not sure if this is related nor why they mention "Debonaire" in the listing's title:
http://cgi.ebay.com/1958-RCA-VICTOR...temQQimsxZ20090623?IMSfp=TL090623157001r31414
Be careful since you are new to tubes. You know you can get shocked
even when it's all unplugged right?
http://cgi.ebay.com/1958-RCA-VICTOR...temQQimsxZ20090623?IMSfp=TL090623157001r31414
Be careful since you are new to tubes. You know you can get shocked
even when it's all unplugged right?jjman said:Not sure if this is related nor why they mention "Debonaire" in the listing's title:
http://cgi.ebay.com/1958-RCA-VICTOR...temQQimsxZ20090623?IMSfp=TL090623157001r31414
Be careful since you are new to tubes. You know you can get shocked
Thanks for finding that. My console looks like the top right hand pic, but the legs are not like that, they are stout and part of the woodwork, and the grill cloth is dark brownish color.
I am seeing if I can borrow a digital camera so I can take a bunch of pics of the front, back, chasis.
Bloody hell! I replaced the capacitor for the left (dead) channel,
and it is still dead, or near dead! Now what do I do?
Would it be a good idea to change the resistors? What if they are all good like the two original capacitors I just cut out which were good in the first place?
I couldb't find any information whatsoever on this damn radio.
Not the amp, not the tuner, nothing!
What if the left output transformer is blown, what then?
I hear they are dicustingly expensive little beasties!
I am not an expert here, I am hitting a wall, what should I do next? Thanks.
and it is still dead, or near dead! Now what do I do?
Would it be a good idea to change the resistors? What if they are all good like the two original capacitors I just cut out which were good in the first place?
I couldb't find any information whatsoever on this damn radio.
Not the amp, not the tuner, nothing!
What if the left output transformer is blown, what then?
I hear they are dicustingly expensive little beasties!
I am not an expert here, I am hitting a wall, what should I do next? Thanks.
Bloody Hell! I swapped a good capacitor from the good right channel, to the wiring for the left (dead) channel and still the left channel is dead, or nearly dead! It is still extremely faint if I crank up the volume. I am not an expert here, I am creeping along slowly, and now I am hitting a wall.
What next? As I see it; the caps are just fine, I cut out two good caps to later find out they were perfectly good.
What would cause a channel to go bad like this!?
If it is the bleedin output transformer then what then?
I hear those buggers are very expensive to replace.
What if I replace all the resisters? I mean do I replace everything, spend all kinds of money blindly? What could it be that is causing the left channel to be bad!
The problem is in the amp section. Help me please, I am out of ideas!
What next? As I see it; the caps are just fine, I cut out two good caps to later find out they were perfectly good.
What would cause a channel to go bad like this!?
If it is the bleedin output transformer then what then?
I hear those buggers are very expensive to replace.
What if I replace all the resisters? I mean do I replace everything, spend all kinds of money blindly? What could it be that is causing the left channel to be bad!
The problem is in the amp section. Help me please, I am out of ideas!
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