Originally Posted by cvrbob
start with first replacing the memory battery, then the circuit module
you can use the 529A ( 820D ) or the
533B (820D2 )

It will work just fine with a dead battery. Battery is just to maintain the programming during power interruptions. So don't waste your money.

Red light means the power supply has a problem. You might be able to find an 820 carrier with power supply on ebay if you want to spend the money. These things are getting scarce because they are so old and it's tough to find working ones.

-Hal

Last edited by hbiss; 02/20/13 01:51 PM.
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