[Discuss] Weird issue with my Sony Trinitron CRT monitor in console mode

[Alan W. Irwin]

Hi Peter:

Thanks for your reply some time ago which I have delayed answering until now
because I had to wait to try one of your suggestions.

On 2008-02-28 14:04-0800 pw wrote:

> Alan W. Irwin wrote:
>> 
>> * What kind of monitor hardware problems would only show up for the Linux
>> console
>
>
> How old is your CRT monitor?

Bought in 2001.

>
> You're changing the frequency (console vs X) that your monitor needs
> to scan.
>
> Some Electronic Possibilities:
>
> Your fly-back transformer may be unhappy at the lower frequency
> used by the console mode. It's part of a tuned circuit. Some monitors
> have some switching going on to change windings used on the fly-back
> for different scan modes.
>
> OR
>
> A component on your CRT controller board may be
> starting to go. Again this can be related to switching
> scan rates in the circuit.
>
> OR
>
> You may need to blow the dust out of the guts of your monitor

I just had a chance to try that.  It was a bit of a dust storm so I had some
hopes the cooler components that resulted would solve the issue, but the 
issue still remains.  Also, the power was off quite a while for the blowout.
Thus, the restart of the monitor was for pretty cold components but the
problem appeared immediately.

>
>
> What are the scan rates in console mode as compared to your X settings?

Console mode is 31.4KHz/70Hz horizontal/vertical frequency.
X mode is 68.5KHz/85Hz horizontal/vertical frequency.

The allowed ranges are 30-96KHz/48-120Hz horizontal/vertical frequency
according to the manual.  But I do take your point that the frequencies are
substantially different for console mode so whatever progressive failure is
occurring could affect console mode first.

> Do you see the same flicker in X

Nope.  X is still rock solid.  Also, the problem is not Linux
software-related because it appears in the POST phase of the boot as well as
Linux console mode. It's quite possible it is some cheap part going bad, but
it appears it would take a lot of effort/expense to find the source of the
trouble, and when you did it might be an expensive component.  Thus, if/when
the problem gets bad enough to affect X, I will do one more test of the
monitor by attaching to another computer to assure myself it is not the
integrated video chipset on my current computer. If it definitely appears to
be the monitor I will regretfully recycle it and buy a new LCD to replace it.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
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