CurtPalme.com Home Theater Forum

richtr8 · Joined: 20 Oct 2025 Posts: 3 Location: Victoria, Australia

hi there,

i'm a brand new user from australia. i know it's very, very late in the game as far as these machines go, but i just pulled out a graphics 800 that i have owned for over a decade, but have never turned on. i had it stored by another CRT enthusiast for the past 5 or so years & have just retrieved it for testing. it's my 30th birthday this weekend, & i intended to demonstrate the projector at a public gathering of 30 ~ 50 or so people to celebrate, but of course it would be a miracle if this thing worked at all having never been tested in over a decade Mr. Green

i have a pretty decent knowledge of electronics & HV/CRT applications, & have the system in the following state:

- powering on the projector, we get fans spinning & LED lights, & i can hear the high frequency sound of HV starting up, but no image. the tubes stay dark.
- on the focus board, the red scan fail LED is on, & the HTHD light is off. the other yellow LEDs are all on.
- there is no red light on the EHT board.
- it seems like the H board has undergone a lot of repairs - all of the mosfets have been resoldered. i did not manage to find any shorts in them when testing them against the heatsink.
- as far as the V board goes, it seems to be working normally as far as i can tell. the red "no signal" light properly turns off when i feed the projector S video & select the source.
- when i pulled the SMPS board, i found cracked solder joins around one of the big caps, which i repaired. no change.
- the green HDHT lamp on the SMPS sub-board does not light up.

as far as i can tell, it seems like i have some kind of error with the H or V board, which is causing the scan failure that deactivates the HTHD voltage. i have searched this forum for similar errors & looked around on avs forum as well. i'm equipped with the service manual & an infinite supply of patience.

i seek knowledge from experienced owners, & possibly replacement parts/boards (which i know are getting quite rare these days,) & basically intend to use this thread as a repair log. i'm passionate about this projector in particular & am confident that with the right amount of time & effort, this projector will run. Thumbs Up

thanks in advance!

**Curt Palme** · Posted: Thu Oct 23, 2025 1:23 am Post subject:

You're on the right path, and I think the H shift board can cause the SF light as well to come on. You'll need to check for H and V sweep. Don't forget to work the H and V yoke switches back and forth a few times as well. Corrosion/bad connection(s) in those can cause the SF as well.

barclay66 · Posted: Sat Oct 25, 2025 10:50 am Post subject:

Look up the section in the service manual where the Scan Fail logic is explained. It’s one signal line only, but it passes several modules and if any of them has a problem, it will trigger the Scan Fail. I would recommend following its path and checking out every module it passes.
As soon as you identify a module with a problem, concentrate on the signals/voltages it needs for operation first and if those are present, check for faults on the module itself.

**Curt Palme** · Posted: Sat Oct 25, 2025 6:59 pm Post subject:

I'd have to look, but I may still have module extender cards here for the 800. Makes troubleshooting a ton easier.

richtr8 · Joined: 20 Oct 2025 Posts: 3 Location: Victoria, Australia

thanks all for the input + advice so far.

Curt, if you have a riser card kicking around, that seems like it would be a lifesaver for testing stuff whilst it's running. do you have any advice for checking out the H & V sweep, such as test points or reference values, etc? apologies if this should be obvious to me. thanks also for the advice on throwing those yoke switches too - i'll definitely give that a try.

as for the scan fail logic, i did go over a few sections of the service manual about EHT hold down & scan fail, but i'm not sure which specific pages you are referring to. if there is something like a flow-chart, that would make it a bit easier to know where to begin looking. at the moment, it'll take a few more sessions of fault finding before i fully understand each section of the path you describe. thank you very much barclay66, i appreciate your advice. seems like you have been down this road a few times before Cool

i suppose i'll study the service manual & try to find what you're talking about when i next take a stab at it.

thanks again!

barclay66 · Posted: Mon Oct 27, 2025 10:46 pm Post subject:

Hi,

I was referring to the section which describes the frame. There is a schematic which shows where the Scan Fail signal runs through. No flowchart or similar unfortunately.

richtr8 · Joined: 20 Oct 2025 Posts: 3 Location: Victoria, Australia

a small update: i haven't fired the projector up in a while as i've just managed to find a couple of replacement boards - namely the H deflection & SMPS + G2 boards. i chose those two boards out of a few others as they seem to be the most commonly-failing modules. they were had for a pretty good price, but half of that was shipping due to me being in australia & the parts being in france. i guess i should count myself lucky, looks like for some money i'll be given the chance to spin the wheel on whether totally replacing these modules does the job or not.

either way, it's going to be some weeks before they arrive, so i'm looking forward to updating everybody around then Smile