Hey /diy/, i opened up my receiver (kenwood krf v7010) because

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Also, does one of you know what this display technology is called, so I can do some research?

its a vfd display, and i think the burned spot is ok on thoose, its the heating filament mark or something

>>1027377
Thanks anon, you were one helpful fellow. Since the display works, if I put some pressure on it, I think, the vacuum is somehow fucked.

>>1027378
Check the LCD`s solder joints on the pcb. May be a cold solder joint case.

>>1027379
Nah, checked them. They were ok

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>>1027377
It's called a getter, and it is a metal spot that is designed to convert free gas atoms into metal, thus "mopping up" any left over air molecules after the device is sealed. This serves to help preserve the vacuum. See https://en.wikipedia.org/wiki/Getter. If this is white instead of silver, it means the device has lost it's seal and is dead. Same applies for the silver at the top of vacuum tubes (which serves the same purpose)

>>1027369
These thing, in a way, operate like a picture tube. A heated element emits electrons towards a phosphorescent element (the actual characters of the display), with a grid in the way to either catch electrons or allow them to pass through. If they pass through the grid, and if the element beneath is charged with a positive current, the element will glow.

If the entire display is dead as opposed to just some specific elements, your first check will be to make sure these filaments are actually energised. You see those fine wires across the front of the display? They should be glowing very slightly (like the electron gun filaments of a CRT, or the filaments of a vacuum tube). They are dim as fuck, so you'll need to turn the device on then turn all the lights off to check they are lit. If not, get your multimeter out and follow the leads that run to the filament back through the PCB to their power source. There will likely be your problem.

Report findings.

>>1027381
err, sorry, mixing terminology. An element is the same as filament. A piece of wire, under charge, emitting electrons.

>>1027378
Wait, missed this, if it works when you press on it, it's definitely a fucked solder joint. Regardless of how good they look, get your iron out and rework every joint on the display. Be mindful that these displays do heat up a little, constant thermal expansion and contraction from turning the thing on and off will wreck joints eventually.

>>1027383
do it anon, i do this all the time with my friends music amp's, redo all solder joints even if they seem fine since the vibrations of the speakers undo them over time

>>1027381
thx for that explanation about getter, didnt know about, kinda intersting

>>1027383
>it's definitely a fucked solder join

This.

Or a cracked trace on the PCB board. Your pushing on the display closes it. Inspect carefully. Solder a wire across cracked traces.

Replace the capacitor, if i remember correctly those use a negative (-38v) filament voltage.
A bad cap will cause it to dim and die.