First, check which type of protect first.
3 seconds (DC protect) OR immediately shut down (Over Current protect)
How to confirm?
1.Unplug the amp.
2.Remove the metal cover.
3.You will see a long vertically installed pre-amp board mounted next to those large power transistors fixed by 12 screws on a large aluminium heat sink.
4.Remove this long vertically installed board mounted by 2 screws.
5.With 2 screws removed, just pulling this board out and hold it with one hand.
6.Plug the amp and switch it on.
7.If your amp stays ON forever, the problem is from this long board.
8.If switch off at once, the problem is from power amp board.
Try the above- mentioned steps. If DC protect, write an email to me via searching you tube SR600 capacitor replacement. Don't be afraid.
So many people wrote to me.
If over-current protect do the
(O)unplug the amp.
(1)download DS-TX494 service manual.
(2)open the amp metal cover.
(3)measure 7 large white resistors resistance loacated next to power transistors mounted on a large heat sink with black probe touching the middle pin and red probe to first/left or third/right pin.
(4)If this 3 Pins large white colour 0.22ohm x 2 resistor is open with infinity ohms ,
(5)replace it and jot down this channel for example left surround faulty. Usually only 1 channel went faulty.
(5a)When the white resistor didn't burn, "2 channels" were damaged due to bad soldering joint of the large white resistor, however.
(5b)When this happened, time taken of shut-down due to over-current is 3 seconds NOT immediately.
(6)the two large power transistors next to this white resistor 0.22 ohms x2 should also be replaced.
(7)plug the amp
(8)switch it on
(9)if ok, troubleshooting get done
(10)if not ok
(11)replace ALL the components of this power amp channel.
(12)pre-amp section no need to check.
remember if not OK, the replaced 0.22ohm x 2 resistor and 2 power transistors maybe shorted again. Check them first. If OK, replace ALL Components in this channel except 0.22 ohm x 2 and 2 transistors. 0.22 ohm x 2 means left and middle pin 0.22 ohm as well as right and middle pin also 0.22 ohm that are 2 pieces of resistors with 0.22 ohm in a large white 3 pins resistor.
Remember sometimes the
0.22 ohm white resistor is normal. If so, use a digital multimeter to measure the be bias transistor voltage via multimeter diode test function. You can compare the normal value,580mV to 650mV with faulty one,3.2mV. And the CE resistance is 1.8ohms only instead of 3 Mega ohms.