Thai Immigration had a great tool that was available for expats to complete a 90 day check in online and avoid the long trip and wait at Chaengwattana. It had broken down more than a year ago, which then required a fun filled trip the immigration office.
By the way, before you can do a 90 day visa check in, you need obtain a retirement (or other type) visa; here are some suggestions in >>> obtaining a retirement visa in thailand <<<.
The Thailand Visa 90 Day Online Check is great news is the Thai Immigration Authority has now fixed the electronic website for 90 check in online. This graphic is now displayed at the 90 Day Check in room and spells out the instructions. It suggests utilizing Internet Explorer and I did test this successfully on Google Chrome. If you have issues, you might way to try adding the following address to the Chrome exceptions for pop ups: immigration.go.th
The Rules for 90 Day Check In
The guidelines for doing an in person or online renewal are no sooner than 15 days before the expiration, or no later than 7 days after the expirations due date. If you are later than that, you will have to pay a fine of up to 2,000 baht, for the first late renewal. If they issue an arrest warrant (and they do) you can add 5,000 baht on, and very likely a strike against you, if not full deportation. It is always recommended to get it done before the expiration date.
Instructions for 90 Day Check In Online
1 – You will want to click on this link to the website where you select the orange Apply for Notification of Staying in the Kingdom, where you can download a guide PDF. 
2 – Then scroll down to the bottom of the section that says “Apply for Notification of residence when staying in the Kingdom over 90 days.” (right-side roll bar). Click on the box that state “I have read and fully understand the above terms and conditions and agree to accept them” 
3 – It will then take you to a menu, where you select the top option (in blue) and an online TM47 check in form will then come up for you to complete. 
4 – The form should be fairly straight forward to complete. If you need to visit Immigration in person, be prepared to spend a good part of the day there; it is highly suggested to be there before 8am (as early as 6am and leave a notebook on the floor (people use them to designate a queue) Here’s the address for Bangkok Immigration: Chaengwattana 7 Alley, Khwaeng Thung Song Hong, Khet Lak Si, Krung Thep Maha Nakhon 10210. 