CurtPalme.com Home Theater Forum

cuthbertdavies · Joined: 20 Feb 2024 Posts: 1

Hi,

I own an Electrohome Marquee 9500 LC Ultra projector, and I've noticed that "fungus" has started to accumulate on the blue and green guns. I'm wondering if anyone in London, UK might be able to assist me with repairing it. I have a passion for CRT projectors and frequently use them in exhibitions, but I'm hesitant to attempt repairs myself out of fear of causing damage. Any assistance would be greatly appreciated.

Additionally, I've observed that when I turn off the projector, the blue emits a strange, ghostly soft firework effect. Should I be concerned about this?

Thank you.

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4409 Location: Phoenix

Hello

"Fungus" cleanup can be tricky; the glycol may have dissolved a little of the aluminum. You may have some luck draining the glycol and filling with common ammonia and let it sit a few days. Replace with fresh triethylene glycol. If unsuccessful then removing the C element lens may be necessary so the tube face can be scrubbed. One risks damaging the rubber bellows in the process. All of the Allen wrenches needed are inch denominated.

Each glycol chamber holds about 22 fluid ounces. Before loading new glycol, pressure test with distilled water if you removed the C element lens. Fill to the very top with distilled water, install the fill hole screws, and press in on the sides of the rubber bellows, looking for leaks. Water mixes easily with glycol so no need to dry out the chamber.

The blue phenomena may be a problem in the electron gun or the neckboard, which is supposed to slam the electron beam off at power down. This is known as spot kill, to protect the phosphor from scarring.

Good Luck

virusc · Joined: 11 Apr 2007 Posts: 358 Location: Massachusetts

If you use them for business or if you really want to keep it going I would recommend you find a parts machine. Maybe in the mean time you can just swap out 2 CRT's while you work on getting rid of the fungus. I would do this now as they are getting thrown out and not many left. I remember a free 9500 in Europe recently. How many hours on the chassis and do your tubes have any wear?