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Monday, May 14, 2018

Beogram 4002: Final Tasks, Adjustments & Playing Records

It is time to finish up this Beogram 4002 Type 5513 project. As a continuation of the corrosion damage repair I am replacing the 5-pin DIN phono plug.

Here is a nice reference diagram Beolover created a while back that shows the audio path from the MMC cartridge connector to the 5-pin DIN plug.

















I like this diagram because when I am replacing the phono cable plug this shows the phono signals I check continuity on from the Beogram output board connector (P9) to the front of the plug.

Here is a picture of a continuity check for the phono right channel from the phono DIN plug to the output board P9 connector.






















I installed a REAN 5-pin DIN replacement plug that has gold contact pins.




















A note to other DIY folks that do this - Some of these Beogram phono cables have a cable diameter that makes installing the REAN rubber boot extremely difficult. The fit is really, really tight.

Another phono signal related change I made was to return to the output board and install a grounding switch between pins 5 and 6 of the P9 connector. That is signal ground and shield ground respectively. The Beogram 4002 units come with a separate grounding wire so owners can connect their Beogram chassis ground to an amplifier's chassis ground should there be hum in the signal path.
This grounding switch eliminates the need for that extra grounding wire as the switch can be flipped to short the two grounds together in the Beogram if needed. A nice option and the switch is easy to get to.






















One last electrical task is to install the two RPM indicator light replacements (33 & 45 RPM lights). This upgrade of incandescent lamps to the Beolover LED replacement is not for cosmetic reasons. Beolover's ongoing testing of Beogram 4002/4004 DC platter motor stability has shown a positive measurable effect of the LED lamp assemblies over the incandescent lamps. So we recommend them on all of our Beogram 400x restorations.





















































One weak part of the Beogram 4002 design are the mounting clips for the RPM indicator panel into the control panel. The mounting clips are a hard plastic that often becomes brittle over time and cracks. This unit had a couple of hairline cracks so I applied some preventative patches.
































I started the final reassembly of this Beogram unit which includes the service manual adjustments.

The first adjustment is for the Beogram platter height so that the distance from the top of the fixed arm (and tonearm) is 23mm from the surface of the platter. That adjustment is made using the large nut on the platter hub.




















The tonearm lowering limit and pickup arm length adjustments are next.























That is followed by vertical and horizontal arm parallelism.


While the platter belt is still removed I adjusted the tangential arm sensor.




Now for the deck panels and the platter position adjustments.































Everything looks good. I performed the arm balancing adjustments earlier so the final adjustments are for the platter speed trim pots.























This Beogram is cleared for record play. I'll give it a listen as I document this blog post :-).























It looks like this Beogram is ready to go back home to Houston. Now where's my copy of "Houston El Mover"?



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