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This is a follow up to my recent post about the redesigned Beogram Commander remote control board, which now works in both (DC-motor) Beogr...

Monday, March 27, 2017

Beogram 4002 (5513): Final Adjustments and Test Drive with Freddy Hubbard's 1975 Album "Polar AC"

It is always a happy moment when a restoration concludes and another Beogram 4002 sits there in pristine Beoloving happiness playing a favorite album! However, before I was able to enjoy this moment with Freddie Hubbard, the final adjustments had to be done to this Beogram. The first step in the adjustment process is always to get the platter and arms perfectly aligned. The next step is to align the platter with the aluminum panels that surround it, while keeping the chassis floating freely suspended by the spring loaded arms that pull it up. This can be a difficult process since there is very little leeway to get all these parameters properly adjusted.

Once this is accomplished the arm lowering limit needs to be adjusted. This is a very important adjustment since it is the final safeguard against needle loss should the record detection mechanism malfunction. You may have wondered why the ribs on the platter have U-shaped recesses...their main purpose is to give the needle some space in case it is lowered accidentally due to a malfunctioning photodiode in the sensor arm or a confused control system. The lowering limit needs to be adjusted that the needle clears the ribs in those U-shaped troughs:
Once this is done, the tracking force can be adjusted. I usually replace the flimsy circlip that holds the  counter weight in place with a nut that can be tightened. This gives this mechanism much mor longterm stability and it stays calibrated during shipping. This shows the original setup:
and with the M3 nut tightened in place:
Then the weight can be adjusted. I always adjust everything that the adjustment scale is accurate around the 1.2g mark which is the recommended tracking weight for most B&O cartridges:
One more thing before the test drive: This Beogram had missing hood mounting springs. They often get lost when people unscrew the hood mounting bolts. Luckily one can replace them with the springs from Pilot G-7 pens which have a larger than usual diameter cartridge:
I cut them in half and widen their diameter a bit on one end. This allows to fit them to both of the hood mounting bolts:
And the it was time for the test drive. I selected Freddie Hubbard's "Polar AC" album, which he recorded in 1975 for the CTI label. It has some quite awesome tracks on it. My favorite is "People Make the World Go Round" (which has another great interpretation on CTI by Milt Jackson - I'll feature this one some other time on a different 4002!). Anyway, here is an impression:
This near-mint first release record was restored to its original glory with the CleanerVinyl Pro ultrasonic record cleaning system. In fact, we used this lovely restored Beogram to make a before/after video that demonstrates how impressively how well ultrasonic vinyl cleaning works by featuring the People Make the World Go Round track before and after cleaning in a video:

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