On this latest Beogram 8002 turntable project I decided to tackle the capacitor replacement tasks first. I also replaced the phono muting relay while I was doing these electrical tasks...and my soldering iron was hot.
The sequence of working the tasks isn't too important here and I often vary it.
I will start showing the replacement of the two electrolytic capacitors on the floating chassis. They are part of the Beogram 8002 +5 VDC power supply regulation.
These photos go through the replacement from beginning to finish.
Next, here is the old and the new muting relay. The new relay is an Omron relay as was the original. The new relay however it fully sealed.
I changed out the 4C1 capacitor, inside the transformer box next. It is a bipolar type capacitor used in the tangential drive platter motor circuit of the Beogram 8002.
The original 4C1 capacitor is quite large which is probably why it ended up inside the transformer box.
The modern replacement capacitor is a much smaller physical size so we like using a 3D printed mounting plate for it when we do the replacement.
Here are the before and after photos.
When I start on the PCB1 and PCB2 capacitor replacement I do usually begin with the microcomputer board (PCB2) first. So that is the case here.
There is only one electrolytic capacitor to replace on PCB2. That is 2C28 and it is quite important. It is a filter capacitor for the +5 VDC to the microcomputer IC.
The fit is very tight inside PCB2. My method of replacing 2C28 now is to cut the leads first to remove it. Then I desolder the remaining leads. It is much easier that way with 2C28 out of the way.
I also like to remove the microcomputer IC and replace its 40-pin socket at the same time.
One thing to notice regarding 2C28 is that the negative lead has to be soldered to both sides of the board. That is important of course and is easy to overlook.
Here are the new and original 40-pin 2IC1 sockets side-by-side. The new socket is a beefier design with tulip style pins.
Here is the new 2C28 capacitor installed followed by the new 2IC1 socket.
Here is 2IC1 reinstalled.
It is always worth mentioning that you need to follow good electronic precautions for static electricity when handling delicate integrated circuit devices.
Finally, here are the before and after photos of the main board (PCB1) capacitor replacements.
Another important note regarding the capacitor replacement tasks on PCB1 and PBC2...
A problem we have seen before on the two boards is with the solder connections where the board connectors mount to the circuit boards. For that reason we always reflow all of the solder points for all the board connector pins. That is true for other vintage B&O audio components as well.
The main electrical work is done. I still need to add my test connector to the button control panel that makes the service manual adjustment for the scanning LDR devices easier. I will do that in the next step along with cleaning the floating chassis, lubricating and adjusting the tangential arm assembly and changing the servo motor belt.