My S+ shows code 21?

[knagl]

You can post a "WTB" (Want To Buy) ad in the classifieds section of the forum and I'm sure someone will have one they can sell you.

If your current board has a blue volume knob sticking out of the top part of the tray and has a bank of DIP switches on it, it's a 10mhz board.  If it does not have a volume knob or any DIP switches on the board, it's a 16mhz board.  You'll want to get the same kind of board you currently have (likely a 10mhz) -- make sure to indicate that in your ad. 

[mike paris]

Thanks, i hope that will fix the problem.  Mike

[knagl]

I hope so too.  If not, we'll keep banging away at it until we get it fixed.

[mike paris]

So, follow up, just replaced the optic board again with a new one, and it works great, so it was just a bad coin in optic, what are the chances that i buy another and its bad also??  Anyway, wanted to thank everyone for there help, i ordered another mpu board, but wont need it now, oh well, i guess i will have a spare.  Hopefully i can get my money back for the bad optic i bought.  Mike

[knagl]

Glad to hear that your machine is up and running!   

I guess it's up to the company selling you parts as to whether you could get a defective part or not.  I'd highly suggest using one of the reputable vendors who frequent the site here for future parts purchases, as they'll sell you good parts and on the off chance there's an issue, they'll take care of you for the return/exchange.  Jim at Blueridge Slots tends to have a ton of parts, and has a fantastic reputation here on NLG (I've bought many items from him, too).

As far as having a spare MPU board, that's not a bad part to have an extra one of.  They don't frequently go bad, but at the same time it's nice to have one for future troubleshooting.