8MM-16MM FORUM WORLDWIDE

I have just finished servicing a elf RT-2 and have a amp problem when i switch the amp on i get a boom as if its powered on ok but i get no sound from it .
It a mag/optical amp but no sound on both when you turn up the volume there is no sound increase or noise i would of thought someone has powered it on with no speaker plugged in both fuses test ok.
Would anyone know of this problem or what to look for im ok with a soldering iron.
Barry

There were several versions of the amplifier during the production run of the "R" series projectors. Some have two fuses while others have only one fuse. Check the simple things first like look for a blown fuse and be sure all cables and connectors are fully seated in their sockets.

Some versions of the amplifier used those "all-in-one" series of amplifier chips which always go obsolete months after their introduction. Other versions of the amplifier use discrete output transistors which are commonly available to repair the amplifier.

Always check the exciter lamp to see if it's lit when the amplifier is on and the projector is in the "forward" mode.

Additional information on identifying which version of the amplifier you have.

Amplifier version 1:

Has EUH-WA206 etched on circuit board. Uses a 1 amp fast blow fuse in that fuseholder. Has type APA211D "all-in-one" amplifier chip (now obsolete) for the output stage.

Amplifier version 2:

Has EUH-WA414 etched on circuit board. Uses a 1.5 amp fast blow fuse in that fuseholder. Has type 2SC1667 and 2SA837 output transistors bolted to the chassis.

Amplifier version 4:

Has EUH-WA526 etched on circuit board. Has TWO fuses. A 2 amp fast blow fuse mounted in an open fuseholder bolted to the top of the chassis (controls exciter lamp power supply circuit). There is a 2 amp fast blow fuse in the conventional screw-in fuseholder which control just the amplifier audio circuitry).

I have never seen or encountered an amplifier of version 3. I think it might be one made for the UK. Check the "EUH-WAxxx" numbers etched on the pc board.