MVX250i E, MVX200i E, MVX200 ESERVICE HINTS72-3 Faulty of Playback PictureIn the DV, degradation of picture quality normally appears on the screen as block noise. This is because, if an error occurs exceeding theability of the error correction circuit, the block by block information of pictures is not played back properly and thus complemented bythe previous picture information. Normally, such block noise appears on the screen when the error rate has considerably been degradeddue to the degraded tape or the lowered head output, etc. Be sure to check the playback picture quality by the error rate.1) Deterioration of Tape QualityCheck if flaws, kinks, etc. are found on a magnetic face of tape or not, and compare it with the error rate of other unit.2) Error Rate (“SERVICE MODE · ADJUSTMENT” P. 8)In the service mode, check an error rate of self-recording/LP playback. The specified allowable error rate is 2 × 10 -5.In case of NG, take the following procedure.(1) Observe a playback envelope. If it is abnormal, carry out tape-path adjustment.(2) Run a cleaning tape.Use the cleaning tape of hard type (DY9-1384-000).[Playback time]After replacement of the drum unit → 25 secondsFor cleaning → 25 seconds per time* Do not proceed to a playback for 25 seconds or more continuously.* Limit the total of playback time to five minutes.* When using hard-type cleaning tape, select the cleaning mode on the product main unit.(Refer to “SERVICE MODE · ADJUSTMENT” [4-3 - Cleaning Mode] P.10)(3) Check the error rate again.If the error rate is out of the specified range, clean the tape drive parts (posts, drum) using cleaning paper moistened withalcohol.* Take care not to damage the head.* Do not touch the head with bare hand.(4) Check the error rate again.If the error rate is out of the specified range, replace the tape with a new one and check the error rate again. At this step, use atape (must be Panasonic LP tape) which has been purchased at a different time. The error rate may become worse due toinconsistent quality or aging of the tape.(5) Check the error rate again.If the error rate is out of the specified range, replace the drum unit.(6) Check the error rate again.If the error rate is out of the specified range, replace the mechanical unit.
