Both units are clean and run perfectly. I have System 6.0.4 running on the M5120 (non-backlit) with MacPaint installed. I have System 7.0 running on the M5126 (backlit) with ClarisWorks installed. That's how I drew the "hello" logos for both of them. They are fun units to play with and functional to a bit. They can draw, crunch numbers, word process, and print. They can't operate on the internet unless you tried running a 68k version of old Netscape on the System 7 and connected using an external modem. Neither one has ethernet and neither will support the modern AirPort WiFi. They aren't very efficient machines for internet use. I just collect these older Macs and they are in my collection. I take them out for display every once in awhile and I have taken them to my Mac Usergroup meetings. They get a kick out of these older Mac Portables running perfectly. There is a company called NiCd lady that will recondition the batteries and install new gel lead acid cells in the batteries if you pay them and pay for shipping. That's how I got one of my batteries reconditioned. The other one came to me reconditioned.
I had a scare the other night, I plugged my M5120 in to power with the battery installed and got NOTHING. I assumed the battery was 100% depleted. I left it connected for 2 days and last night I heard this noise. The Portable had turned itself on!!! I let it charge overnight and we are a-ok now, the battery is holding a good charge. I have learned you never store the machines with the battery in the bay, you ALWAYS take the battery out when you are done messing with the unit. THe battery can drain if it's in the bay and stored for a significant amount of time. Then you have ZERO power and can not even start the machine. I learned the hard way.