I just sold a Beogram 4002 (Type 5513) to a customer in the UK. The restoration of this unit is discussed in this post. The new owner wanted to be able plugging it in in the UK without using a 110-to-220V transformer (Type 5513 Beogram 4002 have a supply preset for 110V). This issue can be addressed by installing a modern 'universal' power supply that can work with any grid voltage between 100V and 240V (read more in detail about this approach here). In addition to this new power supply he also wanted the Beolover SyncDrive and internal RIAA pre-amplifier installed.
I started the work by removing the hood and aluminum panels:
This unit had already received the Beolover Commander remote control before I put it up for sale.
First I focused on upgrading the power supply. This shows the original 'classic' transformer setup in place. The encapsulated transformer sits right next to the cable feedthrough and behind the fuse box. In other 4002 Types the voltage selector sits beneath the fuse box. In the 5513 type the voltage selector is replaced with a dummy plate and the transformer is directly wired for 110V only.
This shows the modern replacement, a Meanwell RS25-24 power supply which can operate on any grid voltage:
It can supply 25W and has a tunable 24V±~4V output voltage range. 25W is more than enough since all the DC platter motor Beograms are rated 15W. This picture also shows the 3D printed adapter plate that I had to design for bolting it into its proper location, while using the original transformer mounting holes in the enclosure.
This shows the supply with bolted on adapter plate:
I removed the four screws that hold transformer and fuse box in place:
It seems best to cut the secondary wires of the transformer at about 40 mm. This results in long enough leads for connecting the new supply:
I soldered 3mm lugs to the cut off blue secondary wires and to new wires for connecting the new supply to the fuse box:
Then it was time to connect the new input wiring for the MEanwell supply to the fuse box. For this I unsoldered the wires going to the transformer (upper connections in the picture):
and then I soldered in the new red/black wires. Here you can see them emerging from the fuse compartment:
Then I bolted the fuse box back into place:
The next step was bolting the new wiring to the screw terminals of the supply:
Note that the polarity of either connection is not important: The input wires are AC and the blue output wires connect to the rectifier on the main board that previously turned the secondary AC of the transformer into DC for the electronic circuitry.
At this point I also adjusted the output voltage of the supply to the maximum 28V that are possible with the RS25-24. This is done with the white trimmer on the right of the terminals as far clockwise as it goes.
After adjusting the length of the input cable a bit at the cable gland in the enclosure feedthrough I was able to bolt the adapter plate to the enclosure bottom while smoothly routing the wiring through the 'channel' that I designed for this purpose into the adapter plate. This shows everything in place together with the sub-platter (there is a ~9 mm gap between supply and platter, enough for comfortable belt mounting:
Next came the installation of the Beolover SyncDrive. The SyncDrive is a synchronous motor driven by a dedicated digital control system. This gives it exceptional log-term RPM stability, similar to the later Beogram 8000/8002. This shows the original DC motor still in place:
The SyncDrive is a 'bolt-in and play' replacement for the original motor, i.e. there is no need for soldering. This shows it in place:
The red wiring harness connects to the RPM-panel jack on the main PCB. For this a small adapter breaks out the necessary connections to the red SyncDrive harness, while the original plug is also plugged into the adapter:
The final task was the installation of the internal Beolover RIAA pre-amplifier. The Beolover RIAA directly replaces the original output PCB of the Beogram, shown here still installed:
The Beolover RIAA is also a plug and play upgrade, i.e. all that needs to be done is unplugging the original board and then plugging in the RIAA board:
Then the keypad can be installed again.
This concluded my upgrade work on this Beogram 4002. I will now play it for a couple days to make sure there are no intermittent issues, and then it will be time to send it to its new owner in the UK!
