On Sun, 9 Apr 2017 10:21:07 -0700 (PDT), wrote:

"I just went through three weeks of frustration fixing this machine
tool. "

I've found that usually corrupt data is caused by the circuitry, not the EEPROM itself. However your unit is old enough it may have actually failed. When things get old, things get weird sometimes. You see extremely uncommon failure modes and sometimes those "gremlins".

Where I used to work they bought an EEPROM copier cheap. Maybe twenty bucks, but it could not do everything. It did what we needed but it did say that certain types of chips need to be erased before they can be copied onto. The ones in the equipment we worked on did not need to be erased.

These units have a mechanical power switch, so I suspect that sometime the corruption is from turning it off at the wrong time. They are Karaoke players and usually the USB and SD puts became deaf dumb and blind. I had a whole set of them with good data to copy from.

I am somewhat surprised you found a used board for that thing. But since you did you probably should copy the data to either the old EEPROM or a new, compatible one for backup. If it happens once, it can happen again.

I really hadn't heard of that brad of lathe, but if it has Timken bearing, hardened ways and all that it is probably worth keeping for life. That is if you have a use for it. I used to have two lathes but then realized they had been used maybe once in five years I sold them off. Plus I need the room.
The lathe is a great machine and a real money maker. When it runs that
is. 15 HP spindle. One type of job I do on it, 3 and 5 inch diameter
sheaves made from 6061 aluminum, sends the spindle load meter to 120%
for each of the roughing cuts. The chips coming off spray the door
like a sandblaster. Man, I love hearing that. The Miyano rep told me
that they hardly ever need mechanical servicing. The spindle cartridge
is designed so that as it heats up it doesn't expand into the
machining envelope so there is no dimensional change to parts in the Z
axis. Right now I am running a part, also from 6061, that has almost
all the material removed. I load 4 foot long 1.25" diameter stock in
the spindle tube. 2 inches stick out from the collet. The part ends
up being 1.65" long, .25" daimeter but for a .200 thick knurled disc
near the middle. After the machining is done the piece is parted off
and a parts catcher swings out, catches the part, and drops it in a
tray outside of the machining envelope. Cycle time is 47 seconds.
Another job I do is cutting an o-ring groove on the underside of
1/4-20 flat head 304 stainless screws. The groove is normal to the 82
degree included angle of the head. The groove edges have a .004"
radius machined on them to avoid sharp edges. 7 second cycle time.
I'm gonna have to get the EPROMS copied soon as possible. First though
I need to get all the late jobs finished.
Eric