Beomaster 8000 Type 1903 - Michigan Restoration Project - Removing The Output Amplifier Assemblies

The first post of this project left off with the Beomaster 8000 Output Amplifiers needing to be removed from the cabinet.

My first step was to desolder the reservoir capacitor connections for the Beomaster 8000 Output Amplifier +-55 Volt rail voltages.  

It will be necessary to loosen the middle, back panel of the cabinet behind the transformer and reservoir capacitors in order to clear a path for the Output Amplifier assemblies to be removed.

I desoldered the capacitors in a way where the common connection of each set is intact.
I will re-use that busbar on the new capacitors I install later.

The photos show the front capacitors removed.
The two in the rear are held by metal spring clips so they will have to be removed after I loosen the back panel.

I prepared the Right Channel Output Amplifier assembly first.
There are six power connections on the board that need to be unplugged.
Those are for +-55V, ground, +-speaker and headphone.

The associated Output Amplifier wiring has to be cleared out of the way for the circuit board to pass through the narrow opening in the back of the cabinet.

The Right Channel speaker plug assembly must be loosened and moved out of the way as part of that wire harness clearing process.

Next, the two screws holding the heatsink of the Right Channel Output Amplifier to the cabinet must be removed.  

The following photo also shows screw on the back metal panel that were removed.

With everything in the exit path cleared, the Right Channel Output Amplifier board can slide out the back of the cabinet.

That was the easy side.

The Left Channel Output Amplifier removal is much more difficult.
The reason is the opening at the rear of the cabinet is partially blocked due to the Beomaster 8000 cabinet having the metal lid damper assembly mounted next to the Left Channel Output Amplifier.

Because the lid damper platform is in the way for a straight outward removal like the Right Channel, in this case, the Beomaster 8000 Service Manual notes that the Left Channel board must be rotated 90 degrees clockwise for removal.

The following sequence of photos show preparing the Left Channel Output Amplifier for removal and removing it.

It is even more important on the Left Channel to get wires out of the way.  That includes the Left speaker plug assembly.

I have to mention that the step going from getting the circuit board rotated 90 degrees to actually removing the board is a bit tricky.
The leads on the bottom of the board get caught on narrow cabinet opening and the wire harness that goes to the heatsink is rather difficult to maneuver under the lid damper frame.

But it does come out as the service manual instructs.

Maybe getting it back in is easier :-)

I cleared off the rest of the things mounted to the Beomaster 8000 cabinet bottom plate so I could remove it (for cleaning and rust treatment).

After taking the bottom plate outside for cleaning, it is ready for me to work on the rust areas.

That work can be separately from the circuit board restorations.

Here are all of the removed Beomaster 8000 circuit boards...waiting to be restored.