The amplifier, which has two large circular Dianyuan power transformers. 16 high power amplifier tube, double-check 16 amp tubes and direct coupled with small and medium power transistor, capacitor and resistor all normal. Just printed on the amplifier Panel ground wire burned off, with thin wire connections, power up test machine.QzDservice manual download site
QzDservice manual download site
Observing the AC ammeter, current up to lA, and after a few seconds the connection printed on the ground was burned again, suggesting that short circuit "failure". In accordance with past experience in repair, amplifier tube causes Dianyuan c-e Breakdown voltage power supply print or negative Dianyuan power supply wires were burnt out, and this amp tube intact, how can ground wire burned printing? Dianyuan power transformer secondary and case short circuit ring removed, using tables to check, not surprisingly, found to be the case on the floor of a conflict between the screw head and transformer secondary winding. The screws removed, replace the transformer, bond plate ground wire, power up test machine, everything is normal.QzDservice manual download site
QzDservice manual download site
Depicting the short circuit schematic diagram it can be seen that due to the chassis backplane screws have collided with the secondary winding. Screws through the casing, casing and then return to the Center tap of the transformer through a printing plate forming a loop. Transformer secondary coil short circuit to ground, so the plate ground wire burned off.QzDservice manual download site