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Many questions about 4004

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Slava74
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Best regards to the participants!

I recently bought a 4004 220v in a package, no one has ever used a deck.

This is not my first beogram, but I have never seen it in such a new state. It turned out that all functions work, and it keeps speed very well, although a logical replacement of radio components is inevitable .. So far, I have serviced the pancake engine, cleaned and lubricated all the mechanisms, made adjustments mechanical parts according to the manual, replaced the tonearm belt. But such an old thing cannot be perfect, even she hasn't seen music. I would not want to create many topics on the forum, it would not be beautiful. I will ask all questions at once.

1. Hood hinges squeal. How and how to lubricate them so that there are no greasy marks and grease leaks?

2. I have not seen an article about the lubrication of the tonearm motor anywhere, it seems I am not able to understand how to disassemble it.

3. This beogram does not automatically turn on 45 x 7 "speed. This is amazing. All functions tonearms work correctly: start, it defines any record size, return. If I press 45 on the panel, then the speed always works. I suspected the sensor and closed it while driving, and immediately solid tonearm errors began. After that, I was completely confused as to why the transparent plastic striped markings did not work ..

4. How does the deck behave if the largest capacitor is dry? What are the signs?

I will be grateful for your help!

 

 

Slava74
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Slava74 replied on Wed, Nov 18 2020 7:54 AM

Please help with questions! Where else can I ask for help? The best specialists are certainly here.

Dillen
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Dillen replied on Wed, Nov 18 2020 10:01 AM

Fantastic find!

1. Normally there will be no need for any lubrication here.
If never opened since new, the plastics may have developed a certain "chemical friendship" including some friction, that may (or may not) go away with use.

2. Depends on the type fitted. Some will have to be cut open and delicately realigned again when cast back together.

3. Most likely a result of dried out capacitors. There are some tantals in the circuit. I wouldn't suspect the opto as the first thing.

4. If the filter capacitor has dried out, the deck won't do much at all.

Martin

Slava74
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Martin, thanks for helping!

I carefully researched the deck for use, but did not find the slightest sign of exploitation inside and out. The hood has a virgin glossy look, but the hood hinges squeal horribly, especially the one on the left!
This screeching doesn't go away, I've been listening and opening the deck for three weeks now. It seems to be getting stronger every day. I think to drip silicone oil there, but I would like to have different opinions, I am very careful.
(By the way, I was surprised by the complete absence of lubrication on the mechanics. Usually I see dried bad lubricant in the old equipment, but here there is practically none, well, or quite a minimum. Like a new sample from the factory, which they forgot to lubricate.)
****
The tonearm motor is completely walled up in black polymer, it looks like it is filled with plastic, like a fly in amber. Do I need to cut it in half? Maxon brand.
****
As for the speed of 45, I cannot understand how all functions can work perfectly in the deck, except for the automatic switching of speed to 7". Logically, something else should work wrong or sometimes badly, but everything else works well and it works stably. But switching - never. I understood that this is not an optical sensor.

sonavor
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sonavor replied on Wed, Nov 18 2020 5:13 PM

Post a photo of the tangential arm motor.
The actual motor should be inside a plastic housing. Between the plastic housing and the motor there is usually an amber colored padding material (foam) for vibration insulation. Over time that foam can break down. 

Does the motor not operate? If it runs then leave it alone. The service manual doesn't call for any lubrication on that motor. 
No lubrication on the platter motor either. The lubrication on the platter motor comes from oil infused bearings so don't apply any oil from the outside.

Remove the dust cover assembly and turn it over. There are two spring loaded screws on either side of the rear deck that only need to be loosened and the dust cover will pull off. The user manual should show that as well as the service manual. Once you have the dust cover off you will see a long bar spring. You could put a very small drop of oil where you hear the squeak. I would expect the squeak to go away with use though. 

Just a note and some advice...always grab the dust cover with both hands when raising it and lowering it. The spring action is very strong and over time it is common for the hinge area of the dust cover to crack. That can be avoided by being careful with it during normal use.

-sonavor

Slava74
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Sonavor, thank you!

I realized that this motor is maintenance-free. I understood the advice well. I changed all the junk, the destroyed noise isolator, made a modern noise insulation seal inside.
I will try to make the loops on the next weekend, I will write about the result. Now the screeching is such that I feel uneasy. Mostly on the left is strong.

Slava74
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Slava74 replied on Sun, Dec 6 2020 6:20 PM

Hello.

After I asked a question about the automatic switching of the speed to 45 rpm, it suddenly began to work normally by itself. At first she worked once out of ten, then once out of five, then out of three. After a few days, switching to 45 began to work always, and now it is always stable.

I have a question: now when, after playing LP 7", the tonearm returned to the base, the illumination of indicator 45 goes out and for a short moment the relay clicks and indicator 33 flashes. Is this normal termination work?

sonavor
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sonavor replied on Mon, Dec 7 2020 2:31 PM

Hi,

No, that isn't normal. The only relay sound you hear is the muting relay for the audio signal. You should hear that after the tonearm sets down on a record to play. The muting relay should click again when the tonearm lifts off the record. 

-sonavor

sonavor
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sonavor replied on Mon, Dec 7 2020 2:40 PM

I just realized what is happening. It is the speed select relay you are hearing.
You hear that as the Beogram fixed arm scans for a record and the position sensor signals the position for the speed change from 33 to 45. So there will be a "click" there. Once at 45 RPM, when the arm returns to rest the Beogram turns the motors off and the speed select relay would switch back to 33.
That is what you are hearing and yes, there is a brief flash of the 33 RPM lamp as it shuts off. That is normal.

Sorry for the confusion.

-sonavor

Slava74
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Slava74 replied on Tue, Dec 8 2020 12:54 AM

Sonavor, thanks!

Yes, I was referring to the click of the speed relay when the arm returns to base. I was surprised not even by the click of the relay, but by the short blinking of the 33-turn lamp at the end of all operations. In general, a deck that no one has ever used in 41 years seems to wake up. I listened to it every day for a month and the speed 45 never worked. After I asked for help here, it suddenly worked, and now it has been working steadily for a week. This is good, but strange.
I'm used to the fact that old equipment either doesn't work at all, or gradually breaks down more and more. I am terribly interested in how an ancient apparatus should behave, which has not been used after manufacturing. Or is it obliged to work 100%, as it was serviceable 40 years ago? I do not consider dry mechanisms and the condition of rubber, I mean the functioning of radio components.

sonavor
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sonavor replied on Tue, Dec 8 2020 2:44 AM

Well, those turntables are very well made and strong. Audio equipment does not like lack of use though.
One theory about your platter speed is that the relay has oxidation due to the lack of use. Now that you have started exercising it the relay contacts are finally connecting. It would be best to replace the relays of course. At 41 years the platter motor likely could use rebuilding. Check out the Beolover Blog web site regarding that.

Slava74
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Slava74 replied on Thu, Dec 10 2020 12:47 PM

This is hardly a relay. At the beginning of the topic, I said that speed 45 always worked from a key press, but never worked automatically. Now it works everywhere. I looked at the diagram, is the 1C21 capacitor responsible for this? Can such capacitors wake up from forty years of hibernation?

Dillen
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Dillen replied on Thu, Dec 10 2020 2:23 PM

Slava74:

This is hardly a relay. At the beginning of the topic, I said that speed 45 always worked from a key press, but never worked automatically. Now it works everywhere. I looked at the diagram, is the 1C21 capacitor responsible for this? Can such capacitors wake up from forty years of hibernation?

Yes.
And to some extent, yes.

But it will never be a good capacitor again, and the rest of the capacitors will be marginal too.
It's safe to say that all of these decks are in need of a thorough service/restoration in order to operate reliably again.
Caps, trimmers, relays, lamps, cleaning, lubrication, adjustments etc...

Martin

Slava74
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Slava74 replied on Thu, Dec 10 2020 6:59 PM

Martin and Sonavor thanks for all the tips. I am in the process of moving to a new home, so I only gave this deck a full cleaning, lubrication and mechanic setup. But I ignored (of course temporarily!) replacement of radio components. I have, among other things, the education of a radio installer, which I received in my youth. But in my area there is a problem with original high-quality radio parts. I would later like to order a set of branded necessary radio components for my beogram. I hope there are people on this forum who can provide such a service?

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