This is a Magnavox 1970 stereo cabinet (I don't remember the model number). It's a diamond stereo stylus that originally came with the unit. It's been used a lot with both mono and stereo records. However, the problem I have is both unpredictable and occurs with both virgin stereo LPs that I've just unsealed, washed records, or worn ones.
A few facts: I keep the stereo unplugged when not in use to protect from lightning. Fiddling with the volume knob produces a lot of static noise through the speakers, so I leave it at one position. I've checked the wires from the turntable to the speakers and all solders and connections look good.
Here what it does: Placing the stylus on the record, either I get sound from all four speakers (left treble and bass, right treble and bass) or I get three speakers emitting sound (left treble and bass, right bass) and right treble has a low level white noise but nothing from the record playing. I can pick up the stylus and as it bumps a groove, I get brief sound through the right treble speaker. Then I apply a little alcohol to the stylus and there are a few pops through the speakers. I set the needle down and all four speakers emit sound normally. Occasionally, after a minute, the right treble goes out again, but usually sound will come through it normally. This usually fixes the problem while the turntable is turned on until the next day when I use it. Or maybe the next day it still emits sound through the right treble speaker. The point is that I don't think the speaker is the problem since I can fix it temporarily by cleaning the stylus.
My question: This is a magnetic cartridge and diamond stylus. Do magnetic cartridges wear out after so long? Is this a symptom of that? Can I have any dirt or damage to my diamond stylus from it dropping on the turntable perhaps in the past? How can I determine if I need to replace the magnetic cartridge or if indeed this is a problem with my right treble speaker which I doubt? This problem has been nagging me for literally years and I've never found anyone good to ask. Please help if symptoms sound familiar.
Have you tried an IV with a steady drip of alcohol into the stylus?
No, huh?
OK, then try this. I am not familiar with your specific TT but it appears that handling the cartridge / stylus affects change in your listening. If the stylus is removable, remove and carefully clean the contacts with a Pro-Gold contact cleaner. If that does not work or if the stylus does not detach from the cartridge (it is critically important to know whether it does or not prior to attempting to remove it from the cartridge for obvious reasons) remove the cartridge and proceed to clean those contacts. Replace and see if this resolves the issue.
When was the last time you had the unit serviced or tuned up? When was the last time you put in a new phono cartridge stylus?
Sytli and amplifiers do not selectively discard only a portion of the frequency range. The problem is, in all likelyhood, in the speakers, probably a capacitor in line with the tweeter. But, I suspect you have more problems than just a tweeter cap.
The volume control needs to be cleaned as should the entire unit after 37 years. Resistor and capacitor values drift from spec, which were none too tight on the Magnavox line. Parts dry up and need to be replaced and contacts oxidize. If you don't know how much cleaner is too much cleaner, do not attempt to service this, particularly the phono cartridge/styli, yourself. It is very easy to "drown" the contact points of this system and cause far more problems than already exist.
There are online service options for vintage components. Have you done any searching to find someone who might want to, or be able to, service the unit?
Cartridges/Stylii are subject to deterioration over time, even with minimal usage. If this is original equipment, 37 years is a long life for a "needle".
I thought a diamond stylus would last forever. Does it not? Yes, all parts are original 1970 manufacturer parts. I wonder if the magnetic cartridge demagnetizes over several years? I'll definitely clean the volume knob and other knobs to see if that helps the static when adjusting. Since I can't find the manual and I'm at the public library I can't tell the model number, but I'll try to look on the back of the unit. This is a 6-foot long Magnavox unit. If there's a way to describe what the capacitors look like, that would help. I know what air conditioning contactors and capacitors look like but have no idea on a stereo unit. Several years ago, I had a problem with the turntable dragging when playing records. I took the turntable off and cleaned out the spindle which had some junk in it and that fixed that problem, so I'm sure some more cleaning would help. If the dropping out of the right treble speaker only can't be the stylus as a source, then does that mean the magnetic cartridge also can't be the source? What happens to speakers 37 years old? And if it's a problem, how could I get good sound out of it after cleaning the diamond stylus with alcohol? Some of the symptoms don't seem to make sense if it's the speaker. I'd like to follow with the capacitor suggestion if I can find it--that sounds like something that wouldn't be a loose connection problem. After all, you can't fix a loose wiring connection by cleaning the stylus, can you? I've tried to address all the suggestions so far and they bring up the several questions above. Thanks for all the help diagnosing so far. Any further suggestions on my new questions?
I can't really diagnose anything over the internet on a 37 year old console. I suspect the tweeter's cap has dried out or the connections have oxidized over time. The action of cleaning the stylus probably produces sufficient voltage to jump start the capacitor/connection. It then works until you shut the system down.
Cartridges are not frequency selective either but they do wear out just as do styli. Only speakers have the ability to discriminate between frequency bandwidths in the manner described.
Open the speaker and look for any component attached to the high frequency drivers. Probably the only thing there is a cap. This is what has most likely failed. Check all connections, if no problem found, replace the cap.
I really admire the logic in this deduction, Holmes. In fact, this may very well explain a problem that I have been having in an old machine I have been working on(non audio). A 1978 device which is equally selective in its functions. If I kick start it like an old Harley, it works, but not push starting.