Scope help

[awwende]

So the story is, I'm working on a small class D tesla coil/plasma speaker and was working on testing my iphone isolation circuit, which will be using a fiber optic cable. As I was trying to measure an output my screen froze up and displayed an error code:

"Illegal Instruction: 3849F4H"

It's an HP 54600A 100MHz scope (bulky but I love the thing). I've searched google with no luck, and even though it's a copyright 1997 scope I even checked HPs website for technical support (out of desperation). I tried taking it apart to look for a CMOS battery since it displays even after I disconnect and reconnect power, but couldn't find the stupid thing.

Does anyone know what's wrong or how I can fix it?

[Psi]

Dunno,
but here is the service manual with schematics
http://www.home.agilent.com/agilent/redirector.jspx?action=doc&lc=eng&cc=CA&id=1517712&ltype=External%20File

Have you looked over the pcb for anything obvious, like bulging capacitors?

[w2aew]

Various manuals for the that scope can be found on this page:

http://128.238.9.201/~kurt/manuals/manuals/HP%20Agilent/

I took a brief look at the service manual there, and it didn't initially appear to provide much help with respect to any error codes.  In the Troubleshooting section, it describes a couple of built in self tests, and that if they fail, then replace the system board.  Not very helpful for doing a component level repair.  It does describe a little about checking out various systems, so maybe you'll be able to narrow it down...

[awwende]

Yes, I've looked the board over for obvious problems but it all looks fine from what I can tell.

[rf-loop]

I tried taking it apart to look for a CMOS battery since it displays even after I disconnect and reconnect power, but couldn't find the stupid thing.

HP use (Dallas or equivelent ) NVRAM what includes inside Li batteries. You can not measure batt voltage.
I do not know this model NVRAM (I have not anymore these scopes) but I have fixed lot of 5450x series and this model keep cal data in NVRAM. But It can recovery just driving full selfcal routines after first defaulting cal data.

Only what I know about 54600 serie is that it have also NVRAM and typical battery life is (depending many factors) 10 - 20 years. It is HP designed lifetime limit for this product.

If it tell in selfcheck nvram ok, it still do not know battery status.

But first, reset to decfalut (factory cal) and run full selfcal routines.