Today's story comes from an interesting chassis that ran across my bench recently. As mentioned by some of our local gurus like
@mecha &
@zenomorp, the legend of the P538 K7000 goes as follows:
All
19" K7000 Chassis are model
P447, as silk-screened in the center of the chassis, near the HOT
All
25" K7000 Chassis are model
P538, as silk-screened in the center of the chassis, near the HOT
Except that there is such a thing as a P538 19" chassis, as mentioned by the collective many times over the years!
Why? Why would Wells Gardner do such a thing? Does it even exist? Recently
@TheNickDuong sold such a chassis, mentioning it's "rarity". I enjoyed the joke and moved on with my life. As a weird coincidence, I pulled down a chassis I bought a while ago to begin a rebuild on it when I noticed several very odd things:
First, the P447 marking is a sticker. Very odd, but I didn't want to mess with it. This is obviously a 19" chassis as evidenced by heatsink for the vertical IC, the width coil and the B+ resistor value. 19" all the way.
Looking closer, I start to notice other odd things. There's a silkscreen for C69 & the fuse rating is 2.0amp; that's a 25" thing I believe. Also notice there's a header for a pincushion board; also not found usually on the 19" chassis, usually on 27".

Further, C37 is not a film cap and the voltage regulator isn't a STR3123. This isn't really that compelling as parts can be changed. Finally, my curiosity got the best of me.
Gentlemen, I believe I have solved the mystery:
I submit to the collective that what happened was WG was simply out of P447 PCBs and needed to deliver some 19" chassis. So given the PCB is mostly (if not totally) the same, they simply pulled out some P538 PCBs and populated them with 19" components, slapped a sticker on the model number and called it a day. What we've been finding in the wild wasn't meant to be seen. Over the years the sticker falls off and gives us the legend of the P538 19" K7000!