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MZ-R501 display problem.

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otto27

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Hi. The display on my MZ-R501 MD recorder has become invisible most of the time. Occasionally, the text will appear very faintly before disappearing again. Elsewhere, all other functions seem to be working fine. Is there anything I can do to get the display back again? Many thanks. otto27.

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Go into service mode and adjust the voltages. IIRC the very first one should fix the screen - however it's best to do the whole group. Probably no need to mess with the USB stuff (they call it VBs I think).

What you need starts in Section 5-5 on page 18 and finishes before (ie do NOT continue to) the Laser Power adjustment on page 19.

WHATEVER YOU DO, DO NOT DO an NVRAM Reset (page 17) or you will be stuck with learning how to give your baby the Full Monty.

If you can't do these adjustments (no gear or fearful) send to Jim Hoggarth on this board for an adjustment (could send to me but I am far away and he is in the UK).

G'luck

Stephen

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Hi. I don't think it is voltages, as in the adjustable VDD 2.3v line. It is more likely to be the power inverter which drives the LCD on the display board. May be as simple as a leaking capacitor, but more likely the LSI chip on the board.

These displays need a high voltage to work properly (relative to the battery powering the equipment), and need at least three stages of voltage doublers to get the right amount of juice, probably four on this board. Can't tell as the actual display board schematic is not included in the service manual. The whole board is regarded as a single part by Sony.

Jim

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I know that on the NH900 and NF810 it was indeed this first value that did the trick. Jim, I thought you had tried this set of adjustments on several of the other models and reported the same thing?

If the decay has been gradual, I say try it. Jim and I both found that the voltages required were often 20-30 mV too low across the board, and that adjusting them fixed a bunch of problems. As I said, if you do this one FIRST, you may (as I did) see the screen immediately improve. Recommend that if it works, you do the rest in the set (down to where the manual gets into Laser Power).

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Having read this thread again, it occurred to me that this could simply be bad connections between the gold pads on the display board and the equivalent contacts on the LCD glass itself. If the connections are too high resistance, exactly these symptoms can happen. It's the kind of problem that needs a good few sentences to describe, but a simple glance to diagnose. Ghosting, very low contrast, better visibility at different points on the display, etc.

Otto27, as you are in the UK and so am I, would it be worth us getting to the bottom of this? Please send me a private message (PM) to discuss if you wish.

Jim

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