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BRONZE MemberI’m not sure what behavior you are describing. The turntable only detects a 45 record by virtue of it “seeing” the smaller diameter by receiving optical pulses from the ribs until the edge of the 45 is reached. Just prior to that a black line on the clear plastic mounted to the arm transport causes the speed to switch to 45. If you put a 45 12” record on the turntable should behave as if it’s a 33 LP and simply set down on the edge. You have to manually switch to 45 speed. Please describe what happens if you simply put the 45 LP on as if its is a 33 and change the speed right when or shortly after it lowers. If it is not lowering but continuing on, is your LP a colored vinyl that is partially transparent. This can cause it to not drop but is normal. Simply stop the arm with the > control and use the cuing to manually lower.
You can get an extractor tool cheaply. – i.e. https://a.co/d/j3yLCnU. If you are trying to terminate the wires with new pins, that requires a special crimp tool and new pins and housings are available in kits.
Yes you do unless the powered speakers have a dedicated phono input.
This depends on your version. If it has the RIAA preamp, then it is pin 7. If not and you plug in into the Phono input of your receiver, it is pin 6.
Yes, I have all 7 pins. The switch under the front panel PLAY button was very corroded. I cleaned it but it is falling apart, and I can’t seem to position it correctly for it to work when I press the PLAY front. After fiddling with it for hours, I have decided to accept that it doesn’t work. Can I replace it with another type of tactile switch? It seems to be a rather cheaply made board where a piece of tape was holding the metal plate in place. Any suggestions?
It is simply a piece of conductive spring metal that should be able to be cleaned if desoldered. You could switch it with for example the 45-speed one if its damaged. A pushbutton microswitch such as one of these should be able to be retrofitted with minor board modifications, though I have not personally tried it.
Do you have pins 6 and 7 in the phono cable DIN plug? Those can be missing as they screw in and are needed for datalink communications such as turning on your receiver.
Observing from the front and comparing to a clockface:
12 = L
3 = R
6 = LG
9 = RG
You will need to use an ohm meter to identify which wire is connected to which pin.
If you lost all power (no lights or movement) then it is possible that you blew a fuse. These are under a screwed cover in the back left corent accessible from the top. Having said that, the fuse likely blew for a reason. That table is 40 years old and likely needs its electrolytic caps replaced. There are service kits available such as this one from beoparts-shop.com. You do need soldering skills.
You are missing the set-down switch which those wires connect to. See this picture.
I would also disconnect the cartridge signal cables from the RIAA board and check the resistance between the two signal wires of both channels. Depending on cartridge it should be between 800 and 1K ohms. If it’s open or shorted you’ve got a bad cartridge.
No it is not normal and indicates that your phono preamp does not have sufficient gain or there is an issue with it. You did not indicate what cartridge you are using as the MMC6000 has a lower output for example. It would also help if you had a link to the specs of your preamp that specified its gain. Alternatively, I would try to test the turntable into another receiver to see if you have the same issue.
The arm that has the N and R eccentric is marked as 1606 in the service manual. The problem with the diagram is it leaves out identifying details. That a look at the exploded parts view. As to the platters there were two – one with printed spokes and one with rings.
Yes, that capacitor is important as chassis ground and signal ground must not be tied together in the turntable.
Can you take the back right square cover off by sliding the trim forward and snap a picture of that entire area? It’s possible the chassis ground is not properly connected. Also if you remove the cartridge, you should see a small flexible copper tang coming out of the bottom of the black connector. This connection is designed to ground the body of the cartridge since moving iron cartridges with their relatively low outputs are susceptible to hum. If that was damaged or missing that could also be your problem. Here is a link to a picture of the cartridge holder. If you have an ohm meter with the stylus cover on but the arm lowered, you should have continuity {<1 Ohm) between you ground wire and the cartridge shell.
That type of hum is likely a grounding issue. You did not say what the turntable is connected to. If you are using the DIN->RCA adpater then it must be the phono one which has a separate ground wire or you will get hum. If you are going DIN->DIN it may be a bad chassis ground connection in the TT or amp.
The servo should not activate as the arm is lowering. It sounds like the tonearm needs tracking adjustment. Follow the procedure in the service manual.
That problem is generally the speed selection relay and trimmers need replacement. You can find updated replacements from Beoparts-shop.com (now: Danish Sound Parts).
I’m afraid that reading does not make sense assuming you are measuring mAs. What you are looking for is not the steady-state reading but a current jump as you plug it in. I would use a second meter or Oscope to catch the drop in voltage at the time. At this point given your limits and these imperfect medium, I would replace the regulator just to rule it out as it’s very cheap.
You measure current by putting your meter in series with the circuit. This means disconnecting the regulator output, soldering a jumper and using your probes in series. If you have alligator clip ends even better.
The 7805 regulator can source more than 1A of current if working properly which is more than enough to blow the fuse before its short-circuit protection kicks in. I would confirm by measuring the output current when you plug the TT in and see if it exceeds 1A before dropping. If it doesn’t I would replace the regulator. If it does you are not going to have to start disconnecting 5v loads on the board and testing for 5v.
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