Barry777
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Jul 29, 2010, 12:05 PM
Post #3 of 3
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Re: [mf1941] VCR Picture shifts BW to Color
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If the shift occurs in a very strict and regular rhythm, I would suspect the servos beginning to drift out of alignment. If the sound also changes pitch slightly, then the pinch roller might have a flat spot or could be worn unevenly. If the shift is somewhat random, could be worn or dirty video heads or a defect in the color circuits. Aging capacitors can also case weird little problems like that.
At any rate, this is something that probably requires the service manual, a skilled technician and some test equipment to figure out, unless you get lucky and cleaning the heads fixes it. You might also try simply using it for several hours continuously and see if it will work itself out. Subtle problems like these are the hardest to find, since voltages and frequencies will generally still be within tolerance. The good news is that these same problems might also disappear once the VCR is broken back in after probably sitting for years in someone's basement.
Give it a few days and see how it does. My next step would be to replace the power supply caps.
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Barry Fone - VCR Repair hobbyist and professional FAA Repair Station Avionics Bench Technician (top level). TEST EQUIPMENT: (4) Sencore VC93 VCR Analyzers, (11) Tentel gauges, Sencore VA48 and (2) VA62 Video Analyzers, Sigma Electronics TSG-375 NTSC/SMPTE Video Generator, several VCR Alignment Tapes, plus countless Oscilloscopes, Frequency Counters, Wow and Flutter Meters, Distortion Analyzers, Vectorscope, 136-channel Logic Analyzer, Signature Analyzer . . . . VIDEO GEAR: (6) JVC BR-S822U's, (3) JVC BR-7000 series, (3) JVC BR-S500U, (2) JVC BR-S800U, JVC GR-800U and (2) GR-860U Editing Controllers, Sony FXE-100 Video Switcher/Effects Generator, (5) Time Code Generator/Readers, (1) Sony SLO-1800 (Beta), (2) Alesis ADAT-XT, (1) Sony DXC-1200 TV Camera, Pioneer VP-1000 Laser Disc Player plus many consumer grade Beta and VHS VCR's. Passionate electronics enthusiast since 1973...most anything except computers. Check out my collection at www.barrys8trackrepair.com/MyVideoGear.html
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