mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Mon Jun 28, 2010 11:34 am Post subject: |
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| JustGreg wrote: |
As far as values go...I replaced them with the same ratings and BETTER tolerances. I find it hard to believe that the best carbon comp resistor from 15 years ago is superior to a 21st century flameproof |
It's not the tolerance or that a flameproof would make for a better resistor. The circuit they are being used in is considered a "Critical Safety Component" Circuit -- these types of circuits regardless of the type or quality of the components used, their particular and unique variances were critical when the circuit was designed.
| Quote: | | Even in the audio forums they'll tell you a resistor is a resistor is a resistor. As long as it is actually at advertised values, tolerances, and features, a $100 resistor is no better than a RatShack $.049 resistor |
There is a HUGE difference between the circuits used in the HVPS and an any audio circuit. In no way should a resistor be a resistor in this case. In Audio, a resistor is simply that. In the circuits of these HVPS in that particular section, THE resistor used is SPECIAL because the circuit looks far beyond value (it'll still work if the value change). Tolerance (irrelevant here). Features (Must be HIGH Voltage Rated, etc.).
| Quote: | | It will most likely turn out to be something that was teetering on the edge of failure in the first place. I sure as sh*t couldn't do any damage to the PCB in this thing. Not with the iron I was using and the thickness of that PCB. |
I agree.
| Quote: | | I'm a hobbyist and therefore should be exempt from judgement while learning outside my current skillset |
Yes, but as a hobbiest, try to think of it as learning rather than "judgement" 
The Marquee has a perfect platform for the hobbiest to play around in it. But when the HVPS is looked at as something the hobbiest can also play with, the warning is to be careful or to stay away from it all together. Especially considering it's the main thing in the projector that could cause excessive X-Radiation if things are not as they should be. And it's also one of those modules that can also cause tube damage.
And you're not the first person over the years to post about having failure problems after changing a few parts in the HVPS.
So if I could make a suggestion to the Marquee hobbiest out there. It would be that the HVPS should be serviced or up-graded, modified ONLY by someone with a more solid understanding of electronics and the circuits used in that HVPS. There's really too much to risk otherwise!!
I think when the hobbiest gets to the point of making changes to the HVPS, they should contact Curt and have him do the upgrade, changes or modifications for them. he'll know what to change and what not to change, as well as, what circuits to stay away from and what parts to use during the changes that would avoid the possibility of failure and safety issues.
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