Testing with tubes terminal 7 read 1vdc instead of 170-230
- Thread starter DPetrini
- Start date
Can we see the bottom of the PC board and the socket wiring?
What is your resistance to ground on terminal 7? Does that red wire touch pins 8/9 on the tube socket? If it does, that will give you very low voltage on terminal 7.
Hi Paul, do you want I Measure the resistance between 7 and 8 with tubes and power on or not? Better double check before making disasters. I trieds now with no power and no tubes and read 4Mohm and the value continue to increase.
About the cable, i haved distanced the Red cable. After the change still read same voltage(0.961VDC). I can locally order the 4 transistors and i might replace all 4 Just to be sure. Unless other indications from you. Thanxs
About the cable, i haved distanced the Red cable. After the change still read same voltage(0.961VDC). I can locally order the 4 transistors and i might replace all 4 Just to be sure. Unless other indications from you. Thanxs
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Now it looks like pins 1 and 2 on that 9 pin socket shown are touching.
I would not replace the transistors, as an issue like this is the output of the C4S being pulled down below any voltage present on any pins of any of those transistors, so it's likely external to the C4S board. You can check this by rotating the board 180 degrees and reinstalling it, then see if the low voltage moves to another terminal or stays where it is.
I would not replace the transistors, as an issue like this is the output of the C4S being pulled down below any voltage present on any pins of any of those transistors, so it's likely external to the C4S board. You can check this by rotating the board 180 degrees and reinstalling it, then see if the low voltage moves to another terminal or stays where it is.
I would reflow the solder joints on each MJE5731A.
Remove the wires from OA and OB, turn the amp on, then measure the voltages at OA and OB.
It won't matter for this test.
Measure voltage from amp ground to OA, and amp ground to OB.
What are IA and IB now?
Something is very likely not well soldered on the PC board. Can you take it out and show us the bottom side in better detail?
