Audio, hi-fi and car audio - Robber Baron craps out...

In article , Signal
wrote:
Jim Lesurf wrote:

My DVDR75 crapped out two years ago, thanks to those nice folk at
Richer Sounds I got a Panasonic replacement with bonus hard drive.
Never looked back. Now I would agree the Philips could produce a good
picture, but it suffered the 'chroma bug' error via RBG SCART. You
can particularly spot this on the BBC3 screen with the cartoon
characters when they are off air. I would expect yours to be the
same, which if I recall correctly, was the DVDR70?

Yes. It was. But like your '75 it is now replaced due it failing.

http://www.hometheaterhifi.com/volum...ug-4-2001.html

I can't say that I've ever specifically noticed the above 'bug'. But
this may be because I am used to similar 'comb' effects from interlaced
TV, so would have put it down to that.

I find it pretty noticable over RGB :(

Well, TBH these days I generally record using the Panasonic, but play back
both recorded and commercial discs on my Arcam DV137. But I can't recall
noticing the problem when using the Philips.

[snip]

Yes, I used the service menu, so if you need it I can dig out my copy
of some notes on how to access/use that and let you have a copy. But
IIRC I mainly used it to remove the overscan. So far as I recall, there
was nothing like a 'gamma' adjustment, but there may be a black level
adjustment, etc. Can't recall.

Please! I'd like to check the overscan.

Some delay here. I have been looking on my HD as I'm sure I got this as an
email, and kept a text file. But I can't find that. So I'll have to dig out
the hard copy I made, and scan/OCR that when I get a chance.

FWIW I continue to prefer the CRT and have avoided any 'pixel based'
displays. I've encountered too many people with problems due to things
like vision-sound lipsynch caused by long display delays, and I tend to

The latest crop of LCDs have supposedly fixed this?

Dunno. It was a problem makers started off by pretending didn't exist. They
may now claim to have fixed it, but I've not tried any of the screens so
can't comment.

My main gripes about the Panasonic as a display are that the image size
ands shape tend to alter dynamically with the image brightness pattern,

I don't understnad that???

You probably will when you remove the overscan. 8-]

The overscan disguises the problem. It arises for two general reasons.

1) That the higher the CRT beam current, the more the cathode voltage tends
to 'sag' as the PSU can't cope. This slows the electron beam, and means the
fields used to scan have more time to act. The result is that brighter
parts of the image tend to be 'stretched out' and distort the image.

2) The higher the beam current hitting the screen, the more of a negative
potential that part of the screen area picks up. The electrons do 'leak'
back by flowing across the inner surface, but this potential repels the
beam, and has an effect similar to the above.

The result is most obvious when you see that the sides of the image are not
rectangular, and fluctuate with the brightness pattern of the image.
Overscan hides this give-away symptom as the edges of the scanned image are
beyong the part of the screen which has phosphors. My Panasonic does this
quite clearly. The effect is modest, so does not irritate me, but it can
clearly be seen.

(1) could be cured if the PSU was better. But (2) would require higher
conductivity for the inner surface of the screen, which then may tend to
have an impact on attainable brightness as the conductive layer will tend
to absorb some light depending on the physical arrangements, etc. Matter of
manufacturing details. Perhaps this is one reason why some high quality
CRTs tend to me much more costly. But I don't really know enough about that
area to comment properly.

Do you see the 'goldfish bowl' type effect I'm talking about? Pretty
minor but it's there, top and right, on mine.. eg rolling text is
fractionally smaller in the top 1"

Not in the top inch, but the shape does give circles a slight 'egg' effect.
One of the service menu settings is to tweak this IIRC. So you may be able
to fix this once I can find and scan/OCR my copy of the service menu info.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.audiomisc.co.uk/index.html
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html