Faded display of Sony CDP-X222ES

[wheijke]

I'm found a sad Sony CDP-X222ES, it has the usual skipping at the beginning of a disc problem and this one also has a faded display. It seems like the fading goes in horizontal lines that alternate between faded and bright.
My first guess is to replace the 2 caps that feed the 30v that power the display.

Any other suggestions?

 

[Mooly]

Definitely check the caps as they are a common failure on any equipment with a VFD. Beyond that and it could just be the display itself that is low emission. If there is a "display test" pin on the uProcessor then that might be worth leaving enabled to light all the segments and leave it running like that for 24 hours or more. Faded segments often recover emission with use.

 

[wheijke]

Thanks! Changed the caps for fresh one's but but that didn't fix the problem. There are test points on the display chip that are even accessable on the main PCB display connector with TP1. I suppose i would have to feed the TP +5v to do what you suggest.

 

[wheijke]

While watching the display schematic the 30v only passes 2 dtc114el transistors and 2 resistors to the display, could any of these be failing?

 

[Salar]

I guess you have the schematics, so a description like the following quote should be found:

"FLUORESCENT INDICATOR TUBE FULL LIGHTING MODE
1. Connect TP (AFJin 2 of CN515) to GND (Ground), and turn ON the POWER switch.
2. The bridge check (check for short-circut between pins of the S RAM (IC202 of the servo board)) is performed, and all the FL tubes light up if there is no bridge.
3. When a key other than the stop key is pressed, the corresponding FL tubes lights up. Each time the stop key is pressed, all the FL tubes light up."


But this quote is NOT from a CDP-X222ES, but CDP-X5000.

Found this in the "Servicing Note" early page of the manual.
Maybe there is something similar with the CDP-X222ES

 

[Mooly]

Thanks! Changed the caps for fresh one's but but that didn't fix the problem. There are test points on the display chip that are even accessable on the main PCB display connector with TP1. I suppose i would have to feed the TP +5v to do what you suggest.

You would have to be sure the test points are what you think they are (and not a supply for example... refer to the manual) and then force the logic level to the opposite of what it is in normal use.

While watching the display schematic the 30v only passes 2 dtc114el transistors and 2 resistors to the display, could any of these be failing?

Its quite possible but all the evidence will be there in the voltages and any excess AC ripple on the -30 supply. The filaments on the display will probably be held at some predetermined DC level too, usually with a 4.7 or 5.6 volt zener somewhere in the area.

 

[wheijke]

Thanks for the advice so far. I will take my multimeter and do some measurements and follow the display power trail.

 

[Mooly]

Your first post mentions bright horizontal sections. These will be under the filaments and that does point to the display itself really. If you view it in total darkness the filaments can be seen glowing dull red.

I still think its worth enabling all segments and leaving them displaying for 12 to 24 hours to see if the emission recovers.

 

[wheijke]

I googled once again for anything on the msc62408 master control fld drive chip and found the CDP-X202ES service manual (see picture) that at least gives a pinout for the chip and for pin 23 TEST the following:

"Test mode setting pin. Carries out various operation tests when "L" during POWER ON."

So I suppose like in Salar's post TP needs to be connected to ground and "L" stands for "low". Also TEST pin 23 is connected now to +5v with a 10k resistor accoring to the the X222ES schematic and the TP connection is between pin 23 and the resitor (see picture).

 

[Mooly]

You would have to try it. Curiously the voltage is marked as 0.1v (low) already so measure first with it working and see what logic level its really at. The description seems a bit more than a simple display test although it may do that as part of the test. You might have to press some buttons to sequence through whatever tests it enables.