After some years, again on the bench, a trusty 4352B VCO/PLL Signal Analyzer. A rather specialized instrument, but hard to replace with any more recent instrument, unless you are shopping in the 50 kEUR+ category.

he earlier repair: Agilent 4352B VCO/PLL Signal Analyzer: working! – I left a mark inside the cover, as I typically do after performing significant repairs.

Over time, the display has aged and unfortunately became unreadable. Not a big issue, because there is a connector for an external monitor, but still not very practical to use.

The polarizer can be pulled off, but the glue stinks and is very sticky, would be a big effort to do a polarizer repair.

The LCD, a Sharp LQ9D340H is still available, but the cost is high, even when sourcing from China, about 200 EUR a piece. Note: don’t mix up the LQ9D340 with the LQ9D340H – these are not necessarily compatible according to the datasheets.

After some study, I found a good offer for a used LQ084V1DG21 8.4″ 640×480 Sharp LCD panel. These are compatible with the 340H.

Offer of a German IT used parts seller:

The used panel had a special adapter – not compatible with the Agilent flat ribbon adapter of the 4352B – removed the screw and the adapter with no problem at all.

The installation went without any trouble.

The new LQ084 is a little thicker than the 340H, but it all fits into the LCD compartment.

The backlight driver and even the backlight cable position are compatible – just needed to plug the new LCD in.

Finally, not too much to do further – close the case, insert the screws, a quick test run.

Flawlessly working – starting up like before – and, I didn’t even have to remove the inner cover or any boards – just the front panel and LCD compartment.