Need assistance on HP 4291b impedance analyzer

[Saw]

Hello and hi everyone.. i need help with an HP 4291b impedance analyzer, been stuck at startup screen just showing 'internal test in progress'..

So far nothing i did can change or get a response from the machine, i have kept it on and waited more than 24hours as well.. thank you in advance

[MathWizard]

Does it have a warranty ? I see it's quite expensive and out of my leauage.

But I'd open it up, and see what the motherboard is doing. Check the PSU section too. A lot of it is probably like a mini-PC, and has a strict startup routine. What happens when ram and rom go wrong.

I'd want to know if just the screen locks up, would you normally hear changes after pressing buttons, like relays?

There's probably some microcontroller or other such chip, that should be sensing this problem, and you would think, would want to time out and reset. Does it do a RAM check and just get stuck and never finish? Does some circuit or chip somewhere not initialize, and rest of it sits there waiting forever ?


Here's a service manual, there's a lot pf troubleshooting sections in there, if you want to open up the HP.

[_rushin_or_draggin_]

I would start with the Service Manual and see if you can get anything from it. Chapter 10 shows what all the tests do. In chapter 5 it says the startup sequence goes through tests 1,4,5,6,7, 9-16. Maybe it is getting hung up on one of the tests? I see test 1 tests a lot of things. Maybe start there? I have attached the service manual. It may not match up with your serial number, but it should have most of the information you'd need.