Mazak 10N Help please

I have an older 86 model Mazak 10N lathe (T-2 controller) that was working fine and now I have #23 NMI battery alarm that will not reset. I have looked at the forums and have changed all the batteries on 3 boards from the ni-cd to the ni-mh with lead wires. Many posts said this is an improvement.? They all check 3.78v. for the required 3.6v. I had never lost the parameters. After trying everything that I could read about or think of I did a back up and re-initialized the control. Difficult for me as newbie but I got it with other alarms of paridy, etc but shut it down and restarted all went away except my original #23 battery alarm. I am running a 30hp rotary phase converter made for cnc. Very good 240voltage. I have tried at someone's suggestion shifting phases in case high leg was the problem. No improvement. Has anyone had what charges the batteries on the board go out? Any help here would be much appreciated.

seems like you either missed a battery somewhere or got a crappy battery
there is a little red led on the offending board if i remember ("Bat" maybe)
and yes i have got crappy batteries that did not clear alarm

p.s.

there is a vast knowledge base over on the mazak forum for this stuff

Thank you for the quick reply. I have been away and sorry for late reply. I changed all (3 sets on 3 boards) of the new nimh I had put in for all new nicd in case the charge system did not like the others. Still won't clear. If there are any more I don't know of tell me where to look. I have even looked behind display.
There is a red led on board FX784-8 labeled BT-AL. I figure that is battery alarm. I appreciate that help as it narrows it to which board. It checks 3.9v at terminals and at solder joints on the board. The thing is I only changed all these batteries to keep from having a problem. I never lost parameters or anything. It had just been stored for a while on a pallet and I feared it. It ran fine afterwards and for about a week before I got the alarm. Would the charging system of the board have been hurt by the nimh batteries? Is what is reading the voltage for the alarm bad? Would the board have went bad? I am really at a loss here. I looked at the Mazak forum. Thanks for that as I am definitely a newbie here.
Thank you for any more help.

The FX784-8 and 784-9 are the main Mazatrol and program boards, and the EPROM's on them can fail after a few decades.

You can source replacement boards on Ebay. MAKE SURE the 784-8 and 784-9 boards have "YT" or "YT2" or "QT" or similar either on the Eproms themselves, or on a sticker on the back of the board. These are for lathes.

"YMV" or "MV" are Yamazaki Milling Vertical, so those Eprom boards won't work in a lathe.

Before swapping boards though, I would re-initialize the control. You will lose all your programs, parameters, etc. when doing this, so make sure you have some kind of backup of at least the parameters. (T2 only has 3 or 4 pages total, take pics with cell phone if needed.)

ToolCat