CurtPalme.com Home Theater Forum

[barclay66]

[Flemming]

Yes, and the green works fine with the blue crt board

[Curt Palme]

OK, got it.

[Curt Palme]

OK, got it.

[Flemming]

[barclay66]

Hi,

You could do what gjaky suggested which is measuring if the G2 voltage arrives at the blue neck board. As the G1 voltage is located at the same connector, You could measure this one as well.

BUT: G2 voltage is very high (between 500 - 1000 Volts) so You really should know what You're doing.
And You will need to do some soldering (add some extension wires) because otherwise it will be too difficult to connect the voltage meter.
If You hold the meter's tip directly at the connection point, You could slip off and cause shorts resulting in significant damage!
Again, !!!DOING MEASUREMENTS OF POTENTIALLY LETHAL VOLTAGES INSIDE A WORKING PROJECTOR IS DANGEROUS!!!

If You still want to go this route, I suggest the following:
!!!THE FOLLOWING PROCEDURE IS FOR THE EXPERIENCED OR BRAVE ONES ONLY. I WILL NOT ASSUME ANY RESPONSIBILITY FOR ANY DAMAGES TO PERSONS AND/OR EQUIPMENT!!!

- Get some insulated wire. It doesn't need to be thick. Thickness should be similar to the wires going from the chassis to the neck boards
- Wire colors should be black, red and any other color or at least any kind of marking which makes them unique. Length should be about half a meter
- Get a voltage meter. It should be able to withstand at least 1000V and should be set to DC Voltage measurement
- Mount everything back to its normal position (every tube at its location, everything connected)
- Check the diagram attached for correct location of every cable connector
- Switch on the projector and verify that again the blue tube flashes until the projector shuts off
- Disconnect the projector from power and wait a few minutes
- Disconnect the HV wire of the blue tube
- Remove the blue neck board
- Locate the smaller connector (J40) on the neck board
- Check the second diagram attached
- Solder the black wire to pin 1 of J40 (solder side of the PCB)
- Solder the red wire to pin 6 of J40 (solder side of the PCB)
- Solder the third wire to pin 4 of J40 (solder side of the PCB)
- Mount the blue neck board back onto the blue tube and connect it to the chassis
- Find something which will allow the other ends of the wires to be fixated and separated (at least 1cm distance)
- Switch on the projector. It should stay on as the blue tube's HV is not connected
- Measure and write down the voltage between the black wire and the red wire (G2 Voltage)
- Measure and write down the voltage between the black wire and the third wire (G1 Voltage)
- Switch off the projector
- Remove the wires from the blue neck board. Make sure that the soldered pins of J40 are clean and without shorts
- Mount the blue neck board back into the projector
- If possible, do the same procedure on the green or red neck board
- Report back with the values

[Flemming]

Hi Barclay

I think the test you describe is a little over the top for me

As an alternative could I try use the green neck board on the blue tube but this time keep the green neck board connected to its "green sockets". This way we know that the neck board gets the right voltage ... and the rest of the connectors on the blue tube will stay on the "blue sockets". Will this work?

[barclay66]

Hi,
This wouldn’t add anything to what we know already. Remember: You swapped the green with the blue neck board before. So it is obvious that a known working green neck board used at the spot of the blue tube produces the same error. So it’s quite clear that something is wrong with the signals/voltages being provided at the blue neck board connectors.
What You still can do: Inspect both connectors and cables for the blue neck board. Look if there are any bent pins on the neck board side and the chassis side. Check if any of the contacts has slipped out of the white connector housings.