Hi all.
I have recently got my hands on an NAD 705.
It had a backlight issue which I fixed in no time.
But now I notice the display is fading after about 1 second and it's also jittery (some segments sometimes appear randomly?)
Has anyone ever came across this failure?
Is it the LCD itself?
Can it be the LCD Driver? (Sanyo LC7582)
Please help... 🙏
I have recently got my hands on an NAD 705.
It had a backlight issue which I fixed in no time.
But now I notice the display is fading after about 1 second and it's also jittery (some segments sometimes appear randomly?)
Has anyone ever came across this failure?
Is it the LCD itself?
Can it be the LCD Driver? (Sanyo LC7582)
Please help... 🙏
Trying desperately to bump.
If anyone thinks it is needed I could upload a video presenting the failure. Let me know.
Please help?
😳
If anyone thinks it is needed I could upload a video presenting the failure. Let me know.
Please help?
😳
Please see the link to a video presenting the problem.
Please notice how the display "fades" after turn on on just a few seconds and then after each keystroke (any key) it partially reappears for about 1 sec.
LCD disappearing display
Please notice how the display "fades" after turn on on just a few seconds and then after each keystroke (any key) it partially reappears for about 1 sec.
LCD disappearing display
Hi liquias,
This is a shot in the dark, but I would give special scope scrutiny to display pins 1 and 44 (COM1 and COM2) and their path to driver pins 54 and 53, SM page 23. I suspect they should present as a low frequency square wave.
Good luck!
This is a shot in the dark, but I would give special scope scrutiny to display pins 1 and 44 (COM1 and COM2) and their path to driver pins 54 and 53, SM page 23. I suspect they should present as a low frequency square wave.
Good luck!
OK, I scoped pins 1 and 44, just like you suggested.
pin 1 sits steady at 2.56 DCV (Strange voltage?) and pin 44 is (also steady) at 5DCV.
No frequency, at all.
Do you think this implements the LC7582 is at fault?
maybe the LCD itself is shorting it? How can I tell?
pin 1 sits steady at 2.56 DCV (Strange voltage?) and pin 44 is (also steady) at 5DCV.
No frequency, at all.
Do you think this implements the LC7582 is at fault?
maybe the LCD itself is shorting it? How can I tell?
looking at the datasheet of the LC7582, it makes sense. this resistor (and paired capacitor) is needed to determine the internal clock frequency. when it went "open circuit" the internal clock frequency went to zero. The LC7582 "froze" and was unable to do it's job.
Hope this helps someone else too in the future.
Cheers,
Liquias.
Hope this helps someone else too in the future.
Cheers,
Liquias.