Anyone have a good deal of experience fixing an HP 1980B Oscilloscope?
I¡¯ve just got one and it worked for 5 seconds after I got it then the screen and buttons faded out. I replaced all the defective caps in the unit and still no go on the screen.
I¡¯m able to manually adjust the LED¡¯s by inserting a voltage into the base of the front panel character transistor so I know they CAN work but at the moment not under their own strength.
The LED¡¯s get bright when I remove the module from the front of the unit. I have no control over the RPG control. When it boots up almost all of the LED¡¯s light up so it appears as if the front panel is not talking to the microcontroller.
I have a spare unit coming from eBay next week, but it¡¯s a little frustrating when you see that item that you just purchase work very briefly. I know that it can work. More than likely, some little component died while it was turned on.
I should mention that all test points for voltages are spot on. Also I reseated and cleaned every DIP package IC with deoxit.
Also, because I was able to adjust the LED brightness by manually adjusting the control voltage, it makes me wonder if the CRT is working perfectly fine. It¡¯s just that the control voltage that is just the car and Trace intensity be turned off?
