Sony STR-KS360 Display Dim

You will need to find the schematic, and from that trace the display driver power-supply. That should give you what you need.

Alternately, you could shotgun all the electrolytics around the display board and hope to get lucky. HiFi Engine (free) should have the manual, so I would suggest the first expedient rather than the second.

Peter Wieck Melrose Park, PA

The PCB for the display board is marked "FL700 FLUORESCENT INDICATOR TUBE" which to me implies a vacuum fluorescent display, I find these tend to have a maybe 5 year "half-life" of brightness?

Attempting to "rejuvenate" the display might be kill or cure

Unfortunately, this may turn out to be unrepairable in practice. This receiver uses a VFD (a vacuum fluorescent display). These are, in their essence, small specialized vacuum tubes, with a filament, a bunch of control grids, and a bunch of anodes coated with fluorescent material. These tubes wear out with time and use - the filament ages (its ability to emit electrons decreases) and the anodes age (the fluorescent material emits less and less light when struck by electrons). Eventually they go dark.

The problem is worse for products which leave the VFD powered up (filament heated and drive voltage applied) even when the product is "turned off" - to show a clock, or an "Off" indication, or something like that.

The VFD tubes were usually custom-made for one specific product, or for a product family. Finding an off-the-shelf replacement is probably not going to be possible. It's doubtful that Sony would even sell you a replacement VFD tube if they have one - their "smallest field serviceable spare part" is probably the whole display-panel PC board (which might still be available).

Now, it's possible that the problem could be capacitor-related, I suppose. This receiver derives the high voltage for the tubes using a DC-to-DC converter (oscillator plus transformers and rectifiers and filter caps). There are a couple of electrolytic filter caps on the display board (C703 and C706) as part of this circuit - if one of them has "gone leaky" it might be dragging down the voltage supply to the tube and its driver IC and compromise the brightness.

Checking and replacing these caps _might_ help, but I don't think the chances are very good.

HiFiEngine.com has the service manual (free registration required).

Resolder all of the pins on the display as well. These can crystalize and increase resistance. I have successfully recovered a few this way. Also c heck the power supply for proper voltage levels. Here too it may be a simp le fix. I would expect the display to last longer than this.

Thank you to all who responded. I registered at HiFiEngine.com and downloaded the service manual. What a great resource. I'll open it up soon and see what I can find.

Andy, the link you provided returns a 404 error, but I assume your statement of, "Attempting to rejuvenate the display might be kill or cure." summarizes it.

I'll let you know what I find.

Thanks, Pat

Ah sorry, stick a trailing slash on the URL, I didn't copy it in full

Hey! Look at the pony boy being helpful! You are doing a great job. Don't deviate into trolling. K? ;)

Piss off charger boy.

you're off to a bad start One-Foot.

One foot. Where are you? I want to discuss your... comic books. lol.

LOL. "charger boy"..

I know! If he isn't cursing this is the best he can do. lol. Silly 41usenet.