[Mark-sf]

Since, you found a shorted cap replaced all of them, it is likely the culprit for the burnt resistor. OpAmps usually work fine or simply fail by their nature.  If the sound is now clean without noise and distortion, I would just button it up and enjoy.

[Mark-sf]

If R121 burned, I would replace IC 10 & 11 as they are connected to the same resister. I would also change out C103 & 107 which I believe you are doing.

[Mark-sf]

There are actually 2 dual opamps IC10 and 11. You may be referring to the 100 μF caps on the 15v -/+ rails that help smooth the DC. However, their failure, assuming they opened versus shorted, would not cause white noise in my experience. It is also not likely that both channels would fail together since each has its own dual opamp.  If in fact both channels exhibit the same white noise your problem is likely in the 15v dual power supply section.  This regulation was done discretely back then and is where I would start.

[Mark-sf]

You haven’t mention what component/system it is connected to. If both channels have the same distortion you may be overdriving the input to your receiver as the diigital side sounds fine and once the signal leaves the DAC chip it flows in discrete L/R circuits which are unlikely to both distort unless you have problems with either the +15v or -15v supplies to their opamps.

[Mark-sf]

As far as the coils go those readings should be fine. Hope your restoration goes well.

[Mark-sf]

I don’t see the video; however, you should take a look at the service manual and follow the adjustments in Section 5.1. While doing that take note if it also needs cleaning and lubrication which is covered in 4-8.

[Mark-sf]

You need to use the 120v position AND need to ensure that the fuse in 500mA. If you are unsure of switch end positioning, use an ohm meter between the two AC pins and the 120v one will have about half the resistance of the 240v one.

[Mark-sf]

I would not bother turning it off at the mains daily or even a few days as this stresses components that were intended to have power on continuously such as the those in the power supply. I would only do it for extended vacations of weeks to protect from power surges. Using the 4002/4 models for almost 50 years this way without an issue.

[Mark-sf]

Actually the marks are a wearing away of the matte finish. Some have simply removed the finish entirely or you can check out Rudy’s excellent blog entry at https://beolover.blogspot.com/2022/04/beogram-40024004-keypad-restoration.html.

[Mark-sf]

The tweeter section is on one side of the woofer section, so you ca place a stereo pair with them on the inside or outside as they are mirrored. If doubling up I would have each channel in a WTTW configuration and angled at the listener as you’d want to stay on axis.

[Mark-sf]

The damping cylinder only slows lowering. Raising should be quick. You can turn it more to slow it further. It simply won’t lower if too much.

[Mark-sf]

The screw in the black bottom of the damping cylinder controls the rate of descent.

[Mark-sf]

I have seen the braided cable rise up out of the curved channel as approaching the spindle if it is twisted. Also the bearing height is adjustable. The brass bearing is threaded and with a large locking nut on top. However, that rarely ever is the problem.

[Mark-sf]

I believe that bearing is part of the arm assembly and is not available separately. You will need to replace the entire are or find a parts unit. Most B&O tonearms were a single part number.

[Mark-sf]

Relooking at it the second pin may be there. However, if you had an issue with the knife-edge bearing B not being there, the arm would not work at all. It’s possible the are was not properly refitted. Try following these steps precisely again:

[Mark-sf]

Your picture of Part 1110, Holder, appears to be missing a rear piece S that sticks up and may have snapped off. The only solution would be to find a replacement.

[Mark-sf]

The spring is responsible for restoring the arm to its rest position. It appears you can move it to the proper level with your finger; therefore, it appears the spring has lost tension or was switched with one of the other springs. You should be able to confirm that by pressing on the spring’s top connection. The other possibility is that the counterweight is too far forward which for the tracking weight calibration. Ensure that when the tracking force know is at 0 that the arm floats when in Play mode.

[Mark-sf]

Screw B is the one that you use to align the tonearm with the sensor arm. Also spring 1107 does not appear to be attached at the top in your photo.

[Mark-sf]

It may be that the mute switch needs cleaning. If you try cleaning the stylus when it is at rest and hear anything then the mute switch is not making good contact.

[Mark-sf]

Doubling up speakers that were not designed to be is tricky as it can create interference effects which will result in uneven response and dispersion. If I were to attempt it I would place them so that each sides’ tweeters are in the center as close to each other as possible (pairing opposing channels). This will result in a narrower listening window but will double your dynamics.

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