HP54512B

[femtohertz15]

Hi all,

I just got myself an HP54512B from the bay.  Self tests pass and firmware cal goes smoothly.  4 channels of 1.2ns risetime goodness!   But, it dumps cal after each power cycle.  I think I see the cal ram battery looking straight down between the CRT and the CRT driver board on the left, held in by a clip reaching over the top of the battery.

What kind of battery could I use to replace it?   And, any chance I can pull it and replace using long forceps, or will I need to remove the motherboard to do the replacement?

[TAMHAN]

Out of SWIMBOs and mine own painful experience:

And, any chance I can pull it and replace using long forceps, or will I need to remove the motherboard to do the replacement?

If you ask this about any mechanical process, the answer is NO. Better safe and sorry. I was fast once when trying to repair a DPO, and had to buy another one.

[wn1fju]

I had to pull the motherboard for my somewhat similar HP 54522A.  But then I removed the battery and ran 2 wires out through the back panel which attached to a cheap plastic battery holder (attached to the panel) containing 2 AA-cells.  That way, 1) I can keep an eye on the battery life, 2) I never have to pull the motherboard again to replace the battery, and 3) when they eventually leak (as all batteries in test equipment seem to do), they will leak on the outside of the unit, not the inside!

[femtohertz15]

The battery had welded-on terminals, designed to be soldered into a board, which they were.  I just clipped the leads and ran jumpers to a new battery.   Cals fine now.