I have recently bought a National HRO-5 (octal tubes, rack mount) with a power
supply different from that of another HRO receiver I have, which is the
well-known dog-house type.

I would like to determine whether the new power supply I got is original or it
comes from somewhere else. It is absolutely not an home-built supply, but I
cannot exclude that it was modified by someone in some respects.

You may see it on http://www.qsl.net/i0jx/hro-5.jpg It has a type-80 rectifier,
and the socket on the chassis side has four pins (like the dog-house supply).

Any advice would be greatly welcome.

Also, I would be interested to know where that speaker comes from.

Thanks and 73

Tony I0JX