Without any examination of the circumstances, in a channel to promote A968 C2238 power tubes A1302 and C3281 is burned,rPdservice manual download site
Bootable again a, b two-channel device burnt. Then replace the boost to the aforementioned tube, power tube failure. This receiver without a circuit drawing, draw the circuit after looking up information on drawings below. Open the Cabinet, from the appearance of the amplifier Board is not observed any traces of the element burned because amp short circuit damage, voltage amplification possibilities of damage is very small, so focus from back-level check up.rPdservice manual download site
Channel a and b measured under the push tube, power tube welding without damage. Boot logging a track voltage of 0 Volts between two points a and b, normal should be 2. 2 v, measure D1, D2, D3 and D4 full breakdown, D1, D2 1N4148 substitution available model 1SS252, D3, D4-HZS4BLL 12V voltage regulator tube replacement available; measured R2, R3, circuit breakers, with 1/4W made of gold film resistors substitution; log V5 is not damaged. Power on, power on measuring forward voltage normalrPdservice manual download site
(Denoted by the value in the figure broadly in line). Voltage between two points a and b should be 2. 2V (if not, please recheck the fore elements), the voltage should be at about 45V (without negative feedback). Similarly the b channel check replacement is complete. Will a,, and b two channel loaded Shang promoted tube (with A940, and C2073 substitution), and power tube (with A1302, and C3281), in power tube set electrode Shang series plus 5 ω/2W protection resistance (prevent accident damaged power tube, this a step cannot ignored), boot measurement two channel each points voltage basic normal, each components no fever phenomenon, shut machine split to protection resistance. Other native protection circuits were burned, because of its more common circuit may refer to other protection circuit repair and will not repeat them here.rPdservice manual download site