Rolling picture problem with my jvc hr-xvs30ek

Is it rolling on regular TV or cable channels?

you may want to clean the scart connection every once in a while with a little cleaner like tuno wash. Not a lubed or oil based. 

• SCART cannot carry both S-Video and RGB signals at the same time. It is, however, possible to output S-Video and RGB alternately, (for example, from an S-VHS + DVD combo player), and the TV set will adapt automatically if it understands SCART's S-Video extension. Many DVD players sold in Europe offer the ability to output either RGB or S-Video, which is either selected in the DVD player's set-up menu or by a switch on the back of the system.
• SCART can sometimes be confusing for consumers. Most TV sets that have multiple SCART connectors have only one capable of receiving RGB and the other one capable of receiving S-video. Also, not all SCART cables make use of all the pins, often leaving out RGB signals. In many cases there is also no way to see which type of signal that is currently displayed on the TV set.
• SCART cannot officially carry other non-RGB type (e.g. YPbPr) component video signals, which are gaining ground as an improvement over S-Video in markets where SCART is not used. However, some manufacturers of set-top-boxes and DVD players are known to provide optional (menu-selectable), non-standard YPbPr output through the pins that are officially reserved for RGB color components.
• SCART is not designed to transmit digital video or audio signals. The new (digital) audio+video HDMI connector is often referred to as "digital SCART". From this it appears that there will never be a second generation analog SCART to address the above limitations.
• SCART is limited to two audio channels - meaning it cannot deliver surround sound with discrete surround channels, such as Dolby Digital or DTS.
• SCART connects are non-locking and are prone to falling off or getting loose, especially since the thick 21-wire cable is relatively heavy and often leaves the connector at a sideways angle. Loss of audio or video connection due to a loose SCART connector is relatively common. To allow limited locking, some connectors (such as the one portrayed on this page) have bumps on the sides.
• The thickness and inflexibility of the cables, combined with the fact that they are connected to the plugs at an angle, can sometimes make it difficult to connect items of equipment, especially in confined spaces. Attempts at thinner or flat cables are more susceptible to cross-talk, or are unable to support all communication modes.
• The connector design requires the plug to be perfectly aligned over the socket before it can be inserted at all, whereas most other connect designs are self-correcting if the plug is inserted at slightly the wrong angle.
• Cheap SCART connectors can be very fragile and prone to breaking, losing pins, etc., since they are big and hollow.

Oh no! Big differances from one to another.  Glad to hear from you all.