CT-F950 Flouroscan "ghost"

[aldena007]

I have a CT-F950 on my bench to work on and I noticed the fluoroscan display appears to have some sort of artifact in the display. The display shows the signal strength with bright segments that I am used to seeing with the other units I have/worked on but there is a dim pulsating signal also showing full scale on the display. This ghost signal is annoying and I need to track down the cause. I plan to completely redo the power supply board with all new capacitors/silicon. Will this clear up the problem or do I need to dig deeper?

 

[markthefixer]

dim pulsating signal also showing full scale on the display.

Both channels or one? Full bar or just the end segment?


Making some assumptions:
It's likely - could be power supply ripple, but if it doesn't clear it up, don't be too miffed.
It could be accurately depicting what it is being sent.

 

[aldena007]

Both channels and all segments are affected. The segments all seem to be flashing in sync like it is a 60 Hz signal with the same signal strength. I am going to connect a headphone and see if I hear anything like a hum.

 

[markthefixer]

Your comparison to "other units", are they other CT-F950's?

MANY of the receiver flouroscans are driven by individual Integrated circuits, THIS is a microprocessor driven display. Have to compare apples to apples.

 

[aldena007]

I have seen two other CT-f950's. I have one of my own in production that does not manifest this artifact and another owned by another legacy fan. I have an RT 909 & SA 9800 with nice clear fluoroscan displays but that may not be comparing apples to apples.

 

[markthefixer]

lol by the powers vested in me by the great Karnak, I hearby certify you a CT-F950 display appearance expert.

First the power supply (look for ripple), THEN the caps on the display board.

 

[aldena007]

Thanks for the hint. You must be a Johnny Carson fan.

 

[ChopperChas]

I have a CT-F850 with a similar but slightly different problem. The display is normally dim. When I press Fast forward, the display comes on at full brightness. If I press play, it comes on almost full brightness but flickers visibly.

I bought this unit with a broken tube, and I replaced the entire floroscan board with one out of a parts unit - but a CT-F800, not an 850. the boards look identical though.

Thoughts?

Charles.