Display Pioneer SA 9800

[weber1600]

Hi all,
I have in my possession a pioneer sa 9800 amplifier.
The problem is that the display has no brightness, its lighting is very poor, when pressing the brightness attenuator button, it is practically off.
In normal position the display has no brightness.
What problem can this failure cause?
Thank you

 

[weber1600]

Hello again,
someone who can help me with this problem?
Thank you..

 

[ph2113]

First,check the voltages on Indicator board AWV-002 (VFD display board)
1.Between pin 14 and 15 (ACV): (it should be ACV 4.0~4.3).
2.Pin 10 to GND (DCV): (normal dim:~38Vdc,bright:~30Vdc)

 

[larryderouin]

Fluoroscan the a brand name for PIONEER's fluorescent displays of that era. They can/will dim due to use and/or decay of the tubes internal gases, and after 30+ years many, if not most do. If the voltages that ph2113 alluded to are there, then the tubes are worn out. No real hope for them at that point, as replacements are NLA. But make sure the voltages are up to snuff 1st.

 

[markthefixer]

You need to search on this forum for threads on sa-9800 displays. A fair amount of technical expertise is required to "rejuvenate" the display.
Not many techs remember "rejuvenating" CRT filaments. The filaments (heaters) could build up a kind of "ash" that choked them off.
Operating them for a short while at a higher temperature can displace the "ash" and allow close to normal emission.

For some reason that I have not yet deeply investigated, the Fluoroscan tube used in the SA-9800 was far more prone to have this happening than
many other models with similar but not identical types of vacuum flurescent display.

 

[ph2113]

Rejuvenate the display! One of my three SA-9800s has a dim display too,I am gonna try it.

 

[markthefixer]

this thread: http://www.audiokarma.org/forums/index.php?threads/sa-9800-dim-display-options-for-fix.688648/