Weird behavior from CP650

[Mark Gulbrandsen]

Thing is that EPROM's do not maintain the "Program fully intact for ever. The data begins to deteriorate and you loose stuff here and there. Had this happen with EPROM's in some expensive test gear in the mid 2000's There is nothing wrong with the EPROM's, it's just a characteristic of them. Luckily I found a retired HP guy through an on line group that kindly erased and then re-flashed them for me. In my case the unit would boot to a point and stop, then give an on screen error code.

[Leo Enticknap]

Modern flash memory doesn't, either, though studies seem to suggest that if it is powered up regularly, even just to read, that prolongs data integrity. But as a general rule, if a consumer quality flash stick or SSD is left unpowered for more than 12-16 months, the risk of data rot starts to increase exponentially.

[Jim Cassedy]

Ah I had forgotten they come in that package

Yea- - it would have SOOOO much easier if Dolby had mounted the EPROMS in sockets.
(But why do that when they could sell you a whole board-thingy for a couple of hundred bux
or whatever they charged for them)

[Stefan Scholz]

EEPROM relies on small capacitors charged, and that charge doesn't stay forever. It's actually a miracle how long these ROMS have been usable.
EEPROM was known to us to have a limited lifecycle, like 10 k write operations, whereas battery buffered SRAM could accept endless write cycles.
Just think about it, every preset change or volume level adjustment ends up in a write cycle, that's been why I redesigned a competitor product with RAM and 2/A lithium cell.
Honestly, it's 20 years for the CP 650. In a working productivity environment, you wouldn't use 20 year old legacy equipment for safety reasons.