PT-A40 Feedback pinout?

[norty303]

Try it and see

Theoretically it didn't make sense to me either, but Bill Benner's projector wiring guide also says to only connect the +ve.

If you connect the ground too you'll find the image shifts and distorts. There is an electrical reason why, but I'm not well enough educated in that area to explain it.

Suffice to say that I've got 7 of Guido's boards installed, and on every one of them I had issues with image quality until I lifted the ground. I think it might be because of ground loops or something, with the scanner amps being connected to the scanner PSU and Guido's board getting its ground from another source.

[jors]

Oh I see, to avoid phantom ground loops
yes I read Bill article, so I don't connect negative at input scanners,
thanks for the tip

[norty303]

No input ground and no feedback ground.

[Guido]

Hi,

in my Projectors normally all GNDs are connected to each other (+5V and +/-24V DC Powersupply ).
There MUST be a reference Point to measure Signals.