Hello,
A video of the following description can be seen here:
https://www.youtube.com/watch?v=Pcfv-frF8eA
Long story short: I had to match the VFD circuitry from a Sony CDP-103 to a CDP-502. Both players are from the same age and share the same mechanism controls. All connections, voltages, measurements on the scope (like clock cycles) seem to be o.k., as described in the service manuals.
But all segments of the VFD are illuminated. One can observe this in the beginning of the video.
When the player is switched on, all segments are illuminated from the first second.(But they should be black)
Then, there is additional brightness added to the segments that are "corectly" illuminated. (Like display of time etc.)
So data is displayed correctly, but somehow the segments do not become black where/when they should be.
The only signal in question seems to be the RESET-signal.
It is not described in the CDP-103 service manual but in the CDP-502:
1,5 seconds no voltage when the unit is powered on, this seems
to be the moment, when all segments are lit.
But the voltage is according to the manual, 5 V.
I assume there is really something wrong with multiplexing, maybe someone has advice?
Thanks a lot and all the best,
Salar
A video of the following description can be seen here:
https://www.youtube.com/watch?v=Pcfv-frF8eA
Long story short: I had to match the VFD circuitry from a Sony CDP-103 to a CDP-502. Both players are from the same age and share the same mechanism controls. All connections, voltages, measurements on the scope (like clock cycles) seem to be o.k., as described in the service manuals.
But all segments of the VFD are illuminated. One can observe this in the beginning of the video.
When the player is switched on, all segments are illuminated from the first second.(But they should be black)
Then, there is additional brightness added to the segments that are "corectly" illuminated. (Like display of time etc.)
So data is displayed correctly, but somehow the segments do not become black where/when they should be.
The only signal in question seems to be the RESET-signal.
It is not described in the CDP-103 service manual but in the CDP-502:
1,5 seconds no voltage when the unit is powered on, this seems
to be the moment, when all segments are lit.
But the voltage is according to the manual, 5 V.
I assume there is really something wrong with multiplexing, maybe someone has advice?
Thanks a lot and all the best,
Salar