Need schematic for old Premier 71 Amp

[dude]

A friend picked up this old Premier 71 Amp and I'm trying to find a schematic, no luck so far. I haven't plugged it in as it's not been played in quite some time but my friend did, says it has all kinds of hiss, cuts in and out, unplayable.

The tube layout is two 6L6s, 5U4GB, 12Au7 driver, two 12Ax7 pre-amps and two newer JAN Philips 6189W (never came across these tubes)
I'd like to start by replacing the filters and checking voltages etc.

Some pictures of the exterior, hoping someone can led me to a schematic or so help on what to do first...? Was hoping to have a schematic to follow, don't even know if the tube layout is right?

The speaker is a 15" Jensen, it's old but not the original speaker, looks like the original speaker might have been an 18" as there is a plywood shell around a large hole and cutout for the 15" Jensen. 

I'm thinking mid-fifties or early sixties...? Has two Jensen 3"  or 4"tweeters

THanks in advance,
al

[dude]

More pictures Premier 71 Amp

[PRR]

> 6189W (never came across these tubes)

A fancy 12AU7.

> original speaker might have been an 18" as there is a plywood shell around a large hole and cutout for the 15" Jensen.

No. The extra board is a neat way to put the grille cloth on the back of the main panel, mount the speaker, without having the speaker rim slap the cloth on heavy bass. (You could instead use a thick gasket on the speaker, but that was not common.)

> don't even know if the tube layout is right?

If not marked on the chassis, yes, it is guess-work.

The tube line-up seems reasonable (except the 6189s probably replaced 12AU7s). Hi-gain tube in front, many designers favored medium-gain tubes for tone and driver work.

It will "play" for nearly any likely tube. Juggling AX AT AU7s in same socket is a popular hobby. Sound changes, and it almost always "plays" even with a very-"wrong" bottle in the hole. If you want the designer's original intent, use the "right" bottles; but I suspect the original intent kinda missed the mark, or the mark moved after 1960. At least the tubes are easy to get to.

You expect 350V-450V at 6L6 OT and plates, same or down to 300V at 6L6 screens, working down to 240V-350V of B+ for the preamps. At each resistor-loaded stage you expect the plate to sit at 40%-70% of the B+ for that stage (120V-210V under a 300V B+ node). 12AX7 cathodes sit at 1V-2V, 12AU7 cathodes sit at 5V-10V. Exceptions when you find a cathode follower or a split-load cathodyne.

Are those tweeters in the top corners? Or just Buick-ports? --EDIT- I see one tweeter and its cap in photo 5.

[PRR]

http://el34world.com/charts/Schematics/files/premier/Premier_Schematics.htm

The 76 has very-similar tube set and knob-set. Betcha 90% of it is the same, and that will guide you to any differences.

Whacko tremolo design. Explains why there are so many AU7s in there.

The 88 plans show a 3-speaker config.

[dude]

Thanks PRR, gives me a good start