Help - dim front panel displays on pvr and A/V amp

- B
- Beemer
  
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posted
15 years ago

Thu, May 15, 2008 9:32 AM

My Sony RDR-HX725 recorder of two years age has a problem with its front panel display which is getting increasingly dim. There is a setting where the display can be switched off but there is no dimming control so when the recorder is on it should be at full brightness.

Now it is almost impossible to read if the room is at normal brightness. The recorder is otherwise working okay.

The switched mode power supply only has one potentiometer but I am reluctant to adjust this.

Has anyone experienced the same problem with this or similar Sony recorder?

Coincidentally my Cambridge Azure A/V amp display is also starting to go dim.

I believe that both displays are electroluminescent. Can anone help?

regards,

Beemer

- J
- James Sweet
  
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posted
15 years ago

Thu, May 15, 2008 4:34 PM

I would expect them to be vacuum fluorescent, if they're really EL then they're just worn out, EL degrades fairly rapidly with use. First thing to check is for dirt buildup between the display and lense, that can make a big difference. Next, check the filament supply, if this is low, the display will be dark. IIRC it should be about 1.5VAC but may be high frequency which will require a true RMS meter to read accurately.

- A
- Arfa Daily
  
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posted
15 years ago

Thu, May 15, 2008 4:54 PM

All agreed. Also, the caps in the VFD voltage multiplier might be on their last legs, making the -28v supply low. This is a very common problem on all makes and models that use a VFD panel, supplied by a multiplier. Sony also used to have a tendency to run the filament supply for various of their products, via a couple of electrolytics, which used to fail. When they did, as well as the display being dim, you could also see the anode wires in the VFD glowing very slightly. If it had been left like it for a while, this used to cause damage to the display. VFDs also just 'wear out'. When they do, the segments tend to start to look 'patchy' instead of evenly illuminated.

Arfa