I always assumed to to be little stress cracks(usually running vertically through the playfield). A close inspection of the playfield should help find it. I know it sounds funny, but I always take a flash light and shine it at an angle to look for damage, as some planking/damage can be disguised after someone has waxed the playfield. If this is the BSD on the Cincy CL good luck, as I had been talking to the seller but could not ever get up-close pictures.

That is also the only time I have heard of planking being referenced.
I have only seen it on older machines (at least prior to 1990).
It is usually visible but a flashlight is a good idea also IMO.

Best of luck

Isn't it where the grain of the wood starts to crack the paint and therefore become visible in the paint... as though it were a plank of wood...?? As shown below:

That's my guess anyway...

Planking.jpg

I have also heard it referred to as checking.

I believe (really, I'm unsure) that checking refers to something similar but with the cab. At least, that's how I've always heard it used.

Yes planking is cracking in the finish following the grain in the plywood. Certain playfields seem more vulnerable such as the Lenc Smith BSD batches. Has to do with absorbing humidity, temperature fluctuation typically.
Very common on old GTB wedgeheads after about 30 years stored in garages, sheds. Goes hand in hand with backglass peeling I think.

Here is a pic of someones CFTBL that I found on RGP that has planking. Lenc Smith (LS) pfs are notorious for planking. Some of the worst ones were on TZ. You can spot a LS TZ pf just by looking at the door. TAG and Sun Products (SP) are the prefered pfs to have.

DSC_4170.JPG

Finally got a chance to check my BSD today. this'd been bothering me since i read the first post.
whew! SP playfield. thank goodness, BSD is a keeper.

BSD.JPG

Mine's an SP too! Anyone else? BR?

Yeah, mine's a Sun Process playfield too. They do hold up a lot better it seems.

FYI for those checking theirs: You don't have to pull the apron to check (or look under it at all). There will be a a date stamped on the front edge of the playfield, and ahead of it will be an "SP" if it's a Sun Process playfield.

I just bought a BSD and because of the forum I made sure it was an SP PF

TZ = Sp here..guess I'm lucky.

That's kind of what I was afraid of. We had talked about price and they wouldn't budge, so then they want to trade....Funny thing about my basement though, games go in, but they don't want to come out lol. I wouldn't mind a BSD, the one at Louisville Arcade Expo was SPOTLESS, but being such a marginal player, I couldn't get anything going on it. Oh well...

Well I'm glad you thought it was spotless(that was mine at the Louisville show)...but I shopped it out about 3+ years ago.... and its an LS playfield too....

thanks for the tips!
my BSD is an SP as well, phew!