开云体育

I like this series of scopes,? so was drawn to a 2230 (100 Mhz digital storage) at a low price.?? The seller said it lit up but he couldn't figure out how to run it.?? Well neither can I - in it's present condition!

I haven't used the storage models of this series before but after skimming the op and service manuals,? what appears to be happening is, something is forcing the digital side to run one of the "exercisers" every time on power-up.?? For the first few seconds after the beam becomes visible,? I can see normal traces that respond to controls (if you're quick about it) which indicates the analog side is working.?? But then the screen changes to a pair of concentric boxes and center axis lines.? The inner box can be moved from side to side with the horizontal position control but that's the only control that has any effect.?? Nothing other the cycling power will make this display go away.

My best guess is that this is the "Box" exerciser display that would normally be enabled by pressing one of the Menu Select/DISPLAY buttons during power-up.?? If so, then it would seem that something is doing so unintentionally - i.e. a defective switch or a failure in the circuitry attached to it.?? I can see that a "stuck switch" would cause the instrument to run the Box exerciser, but it normally should be possible to exit the exerciser by pressing one of the other buttons,? which doesn't happen.

I looked for a schematic of the front panel board in the service manual but didn't find much.? Is additional documentation on the 2230 available?? If I can get it working I'd use it mostly in the analog non-storage mode.? Thanks for any suggestions!

On 5/5/2025 11:21 AM, ed breya via groups.io wrote:

Likely an internal switch is set to a maintenance or cal mode.

Hi Ed,

Thanks for your comment - I can declare victory and say it was indeed a switch, just not that kind.?? When one of the four momentary push switches is held down at power-up, it runs one of the four "exercisers".? The "box" is what I was seeing, so I thought maybe a switch was stuck.?? What I hadn't considered is that the CPU looks at the NC contacts,? not the NO ones,?? as an ohmmeter check showed that switch #2 was open from both NO and NC contacts to common. I was surprised but after a squirt of De-Oxit and exercising the switch a few dozen times I could reliably read good continuity on both contacts and the scope will now start up and run normally!??? I guess you could say the normally closed contact was "stuck open",? evidently because the internal shorting bar was not in the required position to make contact.

Probably from lack of use since the scope looks like new - even the screw holding the power cord in place wasn't missing.?? A great buy for $20, including a pair of genuine Tek probes!

73, Bob W9RAN