[Premium-Rx] Harris 2368 battery help

[Mac]

Readers,  i have a friends 2368 he has asked me to make work,  I am 
pretty sure the memory battery is kaput, can someone recommend a 
replacement battery please,  and any special precautions to replacing 
these please ..

Also as a heads up im pretty sure he intends to sell this  after i get 
this corrected, he has offered it to me, but i explained i have pretty 
well settled on staying with what i have and only moving toward things 
Cubic oriented, right now he would be pleased to accept 1,000 or more 
for it, he asked what i thought of this value and i shared i have just 
been away from the market too long to speak with any assurance or recent 
experience's

all interest will be shared with my pal,  he is not a ham but an avid 
BCB hunter listener...

Best and all battery help welcomed..  mac/mc  w5mc