Back to life again!
I said in my original post that I had substitued the internal battery (with a bench power supply), but only for a few minutes while I did the tests. Prompted by Chevy's reply I thought I would leave it connected for longer to see if that helped. After one day, no change...
I have an old LCII that has not been used for several years. It was OK before it was stored away. Now I want to use it again I get no chime but a tone sequence and a blank display at switch on. I've replaced (substituted) the PRAM back-up battery but it makes no difference. Where can I get...