Sony BCU-100 Maintenance Manual

Also see for BCU-100: Installation manual

BCU-100 MMSAFETY CHECK-OUTAfter correcting the original service problem,perform the following safety checks beforereleasing the set to the customer :Check the metal trim, “metallized” knobs, screws,and all other exposed metal parts for ACleakage. Check leakage as described below.LEAKAGE TESTThe AC leakage from any exposed metal part toearth ground and from all exposed metal parts toany exposed metal part having a return tochassis, must not exceed 3.5 mA. Leakagecurrent can be measured by any one of threemethods.1. A commercial leakage tester, such as theSimpson 229 or RCA WT-540A. Follow themanufacturers’ instructions to use theseinstruments.2. A battery-operated AC milliammeter. TheData Precision 245 digital multimeter issuitable for this job.3. Measuring the voltage drop across a resistorby means of a VOM or battery-operated ACvoltmeter. The “limit” indication is 5.25 V, soanalog meters must have an accurate low-voltage scale. The Simpson 250 and SanwaSH-63Trd are examples of a passive VOMthat is suitable. Nearly all battery operateddigital multimeters that have a 20 V AC rangeare suitable. (See Fig. A)To Exposed MetalParts on SetFig A. Using an AC voltmeter to check AC leakage.ACvoltmeter(5.25V)Earth Ground0.15 μF1.5 kZ

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