Tek TDS744A broken

[Jeff5]

Hello everyone.  I found a TDS744a for sale that turns on but screen does not work.  I know nothing of Tek scopes and their value.  Would this be a good find and what kind of support can I get to get the scope up and running again.  price is about 200.  May be just a screen and if so I might just run a VGA monitor for the scope.  I saw on you tube issues with the memory and needing to create backups.  Should I stay away from this scope or try my chances?  Would some of you be willing to help me fix this scope?  I know next to nothing on GPIB, memory of that era and writing scripts.

Just a little background on why I'm interested in this scope.  I do automotive ECU repair and looking to get a fast scope to play with automotive Ethernet. Plus I want to play with what Dave does in the videos.  My budget is very low.

Thank you, Jeff

[CaptDon]

For you personally, probably not worth your time. I say this because the absolute cause of the screen being dark is unknown. Anything from main power supply board being dead to a locked up CPU board. The Dallas chips almost certainly need replaced. For people well versed in the 500/600/700 series it may be an easy fix. For someone with no experience it will probably be one of your worst investments. A working fully functional 744A is probably worth upwards of $500 USD. The external VGA is incredibly nice for classroom demonstrations on big VGA flat panel monitors!

[Ground_Loop]

If it is just the screen there are aftermarket LCD replacements, but the investment for that is more than the price of the scope.  Also, I've tried using the VGA output and it is nice for demos, but aligning the soft buttons around the screen with what is on the VGA display is frustrating.  Further, a working shutter display is just gorgeous on those scopes.  Try to find one with a working display.

[rooppoorali]

Here is a tutorial series on repairing Tek TDS744A:

 

[james_s]

Whether related to the display issue or not, the scope is probably going to need a pile of SMD electrolytic capacitors replaced. The leaking electrolyte does serious damage to the boards, these are complex instruments that can be difficult to repair. Great scopes when they work though.