CurtPalme.com Home Theater Forum

JustGreg · Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI

I have my 8500 down for some major room and pj mods and was wondering if I can test a set of tubes I've had around for a while in my working pj without doing any damage to the ps's or anything else.
The tubes came from my first CRT pj purchase; a pj that DHL booted all over hell and back and never did work. I suspect the filaments are shot because of all the dropping it suffered BUT I base that on swapping in all the ps's and boards from another 8500 that is working fine. It could have been the motherboard or backplane or something other than the parts I swapped in. It would be nice to have them as they are all milky white with no burn at all.

Second, if it's OK to take the chance, can I do one at a time as opposed to dropping all three in and making all the connections? I was planning to just use the green location to drop all the suspect tubes in one at a time; but do I NEED to have all three connected to prevent blowing something up?

Not sure if I worded this right but I think you know what I'm getting at. Wink

Thanks!

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

Hello

All three scan yokes must be connected or the set will not boot up; the yoke plugs have interlocks that the sweep boards must see as connected.

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JustGreg · Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI

Thanks Tim. Thumbs Up

Tom.W · Joined: 09 Mar 2006 Posts: 6635

1031 · Joined: 22 Mar 2006 Posts: 657 Location: Finland

It is allways good to test first without filament supply (disconnect P14 connector) then start projector (maybe adjust contrast near 20-30) and look if there is any error led´s lit and hear that HV raises then plug P14 and then there is few seconds time when picture starts to show. if something is wrong then unplug P14 connector and wait until picture disappears. Time, when tubes get full drive (filamet is heated to normal operating temp) is near 5-6 seconds, picture starts to show at near 3 second point after filamets are connected. Without filamet supply there is no fear of deflection burns, also that "3 second" point tubes has no full emission and if there is somesort deflection failure, possibility to have bad deflection burn is smaller.
Allthought marquee has good protection against deflection failures, but anything is possible. I have probably saved few tubes from spot burns with disconnecting P14 plug, when tube started to drive at "full blast" because i had forgot connect G-2 line to VNB..