On 2/24/2011 12:14 AM, Geoffrey S. Mendelson wrote:
Fred McKenzie wrote:
Re-capping applies to antique radios. Since about the 1960s, capacitors
have been made using dielectrics that hold up much better over time.
That doesn't mean a capacitor isn't bad, but you would NOT want to
replace them all. Such a cure could be worse than the disease!

There is a hidden "gotcha" in the ICOM R-70, R-71 and R-71a, and several
tranceivers of the era.

Instead of a ROM chip holding the operating software, it was placed in battery
backed-up RAM. The idea being that it would be easy to upgrade the radio
at almost no cost.

It turned out to be a bad idea and left many of those radios "brain dead"
when the battery died and the programing was lost.

Someone used to sell a replacement ROM chip board that would go in instead
of the RAM chip board. I have no idea if they still do.

So not only would the radio need a new battery, it would need to have the
RAM reloaded if the battery has already died, or replacement with a ROM
chip.

If the battery is still good, there is a way of replacing it without
losing the contents of the RAM.

In defense of ICOM for something that seems insane by modern standards,
the battery lasted for almost 25 years. It may be planned obsolesence,
but they were awfully patient. :-)

Geoff.


Great call there Geoff. I believe there is a group for this receiver on
Yahoo. Or maybe an Icom group, where he could get this fixed/ up to
date. It was an above average radio in it's day, and I hate to see
a receiver die. Lots of Ham and techs who fix radios just for fun.

Drifter...