Barry777
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Jul 24, 2010, 4:10 PM
Post #12 of 16
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Re: [william lan] ECE VCR player cannot turn on
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Hi William, Well, it looks like we're onto something. Electrolytics generally explode when they're installed backwards, as they have a plus and minus side. Generally, there's a large stripe running down one side and this is the negative side in the consumer industry. Also, the plus lead will be a bit longer for faster identification and easier insertion in the production environment. The board is often also marked with the polarity. Whenever possible, designers lay out circuit boards so that all components face the same way - in other words, all negative stripes face the same way, and Pin 1 of all IC's also face the same way. This enables inspectors to quickly find errors and bitch at more assemblers in an 8 hour day. One caution: Military grade caps are the opposite, with the identifying mark on the plus lead. But the plus lead will still be longer. I'll bet you had a backwards cap in there. Also, that 450 volt cap MUST be at least 450 volt rating. This would normally not be in anyone's normal stock of parts, as most values under 10 uF are generally at 50 volts, 63 volts, or sometimes 160 volts. A 2.2 uF, 450 volt cap would almost need to be special ordered. If the right parts were installed correctly, then you might have a shorted voltage regulator IC on the power board. Carry on, Major! . . . 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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