Service manual: Marconi/IFR AN920/930 or the AN1820/1830/1840 Spectrum Analyzer

[volvo_nut_v70]

Hello;

Would anyone have the service manual for the Marconi/IFR AN-920/930 or the AN-1820/1830/1840 Spectrum Analyzers

Many thanks!
Ken

[TheSteve]

I've never seen one around - it is tough enough to find a user manual. Which one do you have and what is the problem?

[volvo_nut_v70]

Hi;

I have a AN1830, LCD display goes all funky with a narrow band of "normal" screen horiz in the middle. You can see characters changing so I suspect the processor is doing it's thing. After shutting off and immediately turning on the image is upside down, with a couple of pieces missing.

I'm leaning towards a bad LCD display, any thoughts/experience?

I have a pdf AN1840 op manual if you want it..

Thanks!

[TheSteve]

I assume it has external video - does that work ok?

[volvo_nut_v70]

Ya, works fine on external video when the display goes south......

[TheSteve]

If the AN1830 is the same as the AN1820 then you can unplug the video card. If you haven't done so I would reseat the video chip in its socket and look for cold solder joints in the process. You might also want to check the power supply that is connected to the back of the LCD unit before really tearing the unit apart.

[DaJMasta]

It does sound LCD or video driver related, reseating the chips/connectors and checking for dry joints is a good starting point for either.  Actually, if the normal video output is good, I'd suspect the LCD driver/cable more than anything - because if the characters aren't being messed up there, whatever system is doing the screen compositing is still properly functional.

Good luck!