I had the internal battery replaced in my 89B recently. The battery was $60 alone, plus $30 to install it. I had to wait about a week for the battery to come in from Honeywell. I had the pleasure to watch the installation. Took about 30 seconds.

This unit uses a Tadiran TL-5104/p battery with axial pin. You can check the internet for this stock number and find suppliers that sell this battery for $6 to $10.

Bruce,

The battery comes with two leads, one on each the positive and negative ends.
The old battery is soldered into the unit, but the leads do not go through the board. He simply applied the iron to each end where it was attached while pulling gently and unsoldered the connection. The old leads have a plastic cover, remove them and place them on the new battery prior to installing.

Obviously an avionics shop must do this to be legal, but I imagine that any radio tech could do this with no sweat.

Thanks you guys, I just ordered the battery. The cheapist I could get someone to do it for here in Phoenix was 275.00 and it was going to take a week.