wigginjs
Joined: 13 Nov 2022
Posts: 3
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| Posted: Sun Nov 13, 2022 4:14 pm Post subject: G90 sync issues at some scan rates? |
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Apologies in advance if this is a 'stupid question'. Cross my heart that I've read the install guide and accompanying service manuals to try to understand this behavior before posting. I just picked up this G90 and haven't set up a CRT projector since the mid-2000s when I had a Sony D50.
My challenge is, when I set the internal oscillator to certain scan rates, the image is garbled (distorted?). The image and menu appear correctly when the internal oscillator is set to horizontal scan rates of 24.83 kHz, 48.36 kHz, 63.98 kHz, 75.00 kHz, 93.75 kHz, and 106.25 kHz. However, when it's set to 15.73 kHz or 31.47 kHz the image is garbled, and the image is completely unviewable at 126.84 kHz and 145.00 kHz. I'm testing this on input A and input B, with or without a source connected. I've fed the projector a 15kHz image via input A (component) and can confirm that this same artifacting or garbling occurs on an input signal as well. Otherwise, I haven't noticed anything unusual about the projector's behavior.
My G90 has a IFB-3D card installed in input B. It's got about 14,000 hours on the chassis and about 4,500 hours on all three tubes.
Images attached for reference. Help and insight greatly appreciated!
James
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HaydnG90
Joined: 22 May 2006
Posts: 1356
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| Posted: Sun Nov 20, 2022 1:34 pm Post subject: |
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You should definitely replace the Dallas chip just for insurance sake. Who knows when it was installed. And there have been known cases of fake Dallas chips being produced, so provenance is unclear. If that fails with the tubes on you will spot burn all 3. And lets face it, at this point all the value is in the tubes so best protect the investment.
Do yourself a favour and get a Moome HDMI card while they are still available. It transformed my G90 running 1080P at 72Hz via a Lumagen XE+ processor
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