I have two of the 4013 chips coming in the mail today since they were so cheap 50 cents a piece but, I think I will try your suggestion first just in case the chip is good. There sure is some great help on this forum!
By doing this test, how should it act if the chip is good or bad?
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This test will confirm all else is good and the chip is bad, if the relay goes off and on.
Gajanan Phadte
Gajanan Phadte
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Well, like an idiot I just went ahead and put one of the new chips in and I still, have the same problem. 😱 I don't know if it could be a bad small transistor, diode or what. I don't suppose it could be a problem with the trigger circuit which has manual, 12v., or audio selections I keep it on manual because I used to just push the power on/off button. Now, when I plug the ac cord in the back of the amp relay K501 clicks and I can feel it with my finger on the relay case, and the other two output relays click to energize that section. I have a schematic for the trigger circuit and also, one which shows a lot of the main board and, standby if it would help to post them. I appreciate all the help and could use more. because of health issues, I have to work a little at a time and take breaks. Thanks! 🙂
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What is the voltage across base and emitter of Q216
After changing the IC, has the circuit behaviour changed from the original.
Gajanan Phadte
After changing the IC, has the circuit behaviour changed from the original.
Gajanan Phadte
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I'll try to get that and post back later. Thanks! 🙂 I think the circuit behaviour is the same as it was at least, as far as just plugging the power cord in but no measurements of any kind. I'm looking up the pinout specs on the 2sa1015 transistor right now so I can try to get the voltage measurement you you asked for.
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Voltage was .735 dc I checked s204 switch by checking for continuity from pin 14 to pin 3 and it seemed to be functioning properly when pushed and not, stuck closed.
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You could pull out transistors this order:
Q217, Q214, Q216
If amp can not be turned on after one pulled out that one is probably bad.
Or you can check it by dmm for short circuits.
Do you mean after I pull a transistor then, plug the ac power cord in and the amp does not come on by its self that transistor could be bad? Because as of now plugging in the ac power cord is how it works can't use the power button at all. I have a diode check function on my dmm I guess I could use to check the transistors with lifting legs or removing? Thanks! 🙂
Yes, if it is off after plugging power cord that means last pulled device is turning it on. But be careful as there can be few transistors bad. So I suggest pull it completely out (removing) and test by diode check.
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I pulled those transistors and they all tested good. I tried unplugging connector CN21B from the board and the amp still comes on? It sounds great when it's playing I just don't understand what could be energizing K501 relay as soon as the ac power cord is plugged into the amp? It's probably something simple but darn if I can figure it out. I know it was mentioned by another member that I should have 15 vdc at pin 14 vdd on CD4013B IC but, I'm reading a little less than 12vdc. Thanks! 🙂
Hi,
If you pull out transistor Q216 the relay will not pickup. It is the one that send the voltage to the relay to enable it.
If you pull out transistor Q216 the relay will not pickup. It is the one that send the voltage to the relay to enable it.
Hi,
Another check that you can do it is turn ON the amplifier and check pin 1 of the chip CD4013B it should read zero volt. When you powered the amplifier cap C234 and resistor R248 will sent a pulse at pin 4 and this will unconditionally reset the flip/flop and pin Q1 will read zero volt. If is it read 14 volts that will set the relay K501. Do the check and report the reading. Like a I said before every time that push the stand by switch the Q1 should toggle if not then it is possible that CD4013B it is bad.
Another check that you can do it is turn ON the amplifier and check pin 1 of the chip CD4013B it should read zero volt. When you powered the amplifier cap C234 and resistor R248 will sent a pulse at pin 4 and this will unconditionally reset the flip/flop and pin Q1 will read zero volt. If is it read 14 volts that will set the relay K501. Do the check and report the reading. Like a I said before every time that push the stand by switch the Q1 should toggle if not then it is possible that CD4013B it is bad.
He has already replaced CD4013B with no improvement.
Operate the switch once and write down voltages on all the collectors of the tranys mentioned for scrutiny seeing that pin 1 of CD4013 is high(11.x VDC)
Next operate the switch once and see that the pin1 is low(anything below 4volts). measure and mention on the drawing both the conditions
Gajanan Phadte
Operate the switch once and write down voltages on all the collectors of the tranys mentioned for scrutiny seeing that pin 1 of CD4013 is high(11.x VDC)
Next operate the switch once and see that the pin1 is low(anything below 4volts). measure and mention on the drawing both the conditions
Gajanan Phadte
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I have everything ready before me to do the voltage tests I'm trying to decide what to use as my common reference point for ground to take my measurements from. I'll be online also, as I'm doing it. I have decided to use one of the output heatsinks as ground reference point to take all measurements from someone please, let me know if there's a better common ground point I can use. I also, turned off the A & B channel buttons on front of amp for safety this shouldn't effect my measurements in the area I'm working on correct? 🙂
Hi,
You can use pin pin 6 and 7 of the CD4013B as a ground reference. They are connected to ground. Also check the voltage at the base of the Q217. Normally it should be low to disable K501. Also check the voltage at pin 4 of the CD4013B when you push the standby switch.
You can use pin pin 6 and 7 of the CD4013B as a ground reference. They are connected to ground. Also check the voltage at the base of the Q217. Normally it should be low to disable K501. Also check the voltage at pin 4 of the CD4013B when you push the standby switch.
The collector v=0vdc on Q217 also 0vdc on collector of Q214 collector volts on Q216= 24.58 Pin 1 stays at 12vdc whether I push the power button or not. Hope this helps. 🙂 The base pin on Q216 also, has 24.58vdc?
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There is no difference if K501 coil is 24V (Q216 collector voltage) or 0V (Q216 pulled out). So, can you pull out relay and check it?
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