How do I find out the year of my amp??

[tyrel]

I just picked up what is apparently a 1971 Sunn Solarus amp and 2x12 cab.
I have no idea how to figure out what year it was actually made in!!
How do I find this out?
The speakers are definitely not originals and I can't seem to find any other definitive markings on it.
I got it from a guy who's sister in-law was going to throw it in the dumpster because it was old and dusty so he has no knowledge either.
Any help would be greatly appreciated!!!

Thanks!!

[EdBass]

Usually there is an inspection sticker with a date on it somewhere on the chassis, sometimes a date handwritten on the chassis in grease pencil.
Sometimes, none of the above.
If that's the case, post some pics of the front and back of the amp and somebody can probably narrow it down for you.

[tyrel]

Thanks for the info!
All I could find was a piece of tape or something (I didn't want to peel it off) that had a number like 027126 or something like that. I know 71 was in there so I assume the amp is a 71. There was also a little metal tab that had the same series of numbers on it and that tab was attached to the inside of the head.
I've got some issues with the amp - the reverb doesn't work, when the bass knob gets over 8 the volume cuts, there's a constant hum if I don't have the non-working reverb knob in the exact right spot (which is different all the time), and the mid-boost causes another hum that doesn't go away when it's engaged. Do you have any clue how much that all that should cost me to fix? In the past, I've only ever purchased brand new gear. When everything is in it's sweet spot on the amp, it sounds incredible!!

[CLD]

You also can examine the potentiometers for date codes, as well as some of the other components.

[EdBass]

Yeah, regretfully the chassis serial numbers have nothing to do the age dating as far as I have been able to determine. As CLD says the pots should at least tell when the pots were manufactured, so that will narrow down the oldest the amp could be.

Pics are your best bet; c'mon, lets see some "Solarus porn"!