Summary

One of JVC's very first 27" flat I'Art CRTs from late 2000. Originally manufactured in Mexico. Early I'Arts such as this model have s-video input on the front. And compared to the F702's, this one has two component inputs as opposed to one.

Manuals

• User Manual
• Basic Service Manual
• Diagrams and Schematics

Notes

Picture quality is quite good. Just has a bit of red-push. If you wish to turn it off, you can do so this way:

• For TV channels, RF, composite, and s-video, you set R Y GAIN and CD MATRIX to “000.”
• Then switch over to component input and turn CMP R Y GAIN and CMP CD MATRIX to “000.”
• After that, red push should be completely eliminated.

The jungle chip is a Toshiba model shared in the D-series and other curved JVC sets for 2001. This chip is rather special in that it supports other video standards. You can enable 48hz, 50hz, and other oddball frequencies in the service menu by setting "V 48HZ" to 001. The jungle has documentation for analog RGB modification too.

Picture tube is a Samsung model. This same tube can be found in many other flat CRTs of the time.

Composite 240p Performance, Disabling Vertical Edge Enhancement

by Eli Krause

I. For composite decoding this set uses a Toshiba TC90A53N, a 3-line digital comb filter. One beneficial feature of this comb filter is its "1-line color dot interference reducer circuit". Depending on the console/revision, dot artifacting ranges from slight to moderate, and blending effects may be broken. Using an external notch filter to decode composite instead^[1] and sending that to the s-video or component input would blend all dithering patterns and remove nearly all dot artifacts.

II. Just as velocity scan modulation is intended to increase contrast at horizontal edges, vertical edge enhancement artifically boosts contrast at vertical edge transitions for composite and RF sources, changing the color palette in the process. To reduce this to its minimum, the high signal sent to pin 17 of the comb filter must be brought low which can be achieved by removing the resistor leading to that pin. On the AV-20D202 and AV-27D302 it is R239 on the bottom of the main board. On the AV-32D502 and AV-32D302 it is R247.