Overclocking in Dell 5046

On Sat, 08 Oct 2005 02:37:24 +0000, Michael Black

Yep, I know. For my sins, I once repaired TVs-monitors.

More a case that the frequencies it's happily following allow the HT generating circuitry to oscillate at a higher frequency - usually at some peak response outside the design range, which in the process consumes a higher current and generates a corresponding increase in the HT - either of which normally provide brief but spectacular effects. It was once a fun pastime to occasionally sacrifice otherwise dead monitors-TVs by deliberately driving the lightly modified line output circuitry at some insane frequency, with the aim of generating a Jacob's Ladder effect of a high-voltage arc travelling up the space between a couple of brbutt rods - one earthed, one connected to the HT output of the line transformer. Think of almost any "Frankenstein's lab" type of movie and you'll have seen it.

But this buttumes that the line sync present on the input is the sole source of the line frequency used inside the monitor and from my experiences, it's only used to synchronize a free-running oscillator which left unattended, runs at or near the intended frequency. Otherwise things could be auto-toasting just as soon as the input sync vanished (unplug video cable, switch PC off first etc.) and the oscillator wandered off doing its own thing.

So I'd take the "very small range of frequencies" to refer to a small range of frequencies that the monitor's line oscillator would reliably synchronize to (the design range) before it becomes so out of range as to effectively become no signal at all - at which point the oscillator just resorts to free-running at-near the intended frequency.

A very useful chip, for its time. I used it on a couple of projects.

I can't think of any instances where this has actually happened, although I can see how it might with some of theveryearly monochrome monitors which arrived with the first floods of IBM-PC "clone" machines. Some of those were very nasty with poor quality circuit design-components, foul quality displays and were inherently unreliable anyway, never mind problems caused by wayward sync frequencies. ;)

Yes - definitely much preferable to have a display saying "Signal out of range" or somesuch instead of a mysterious blank screen. Many will even display the frequencies in use, when asked - a much happier state of affairs.

B. -- Time is what keeps everything from happening at once.