Silicon Bilateral Switch IG04080

[pulsed_power]

Doesn't this point to problems elsewhere in the power supply? Because you tested the IG04080 at the beginning of this thread and it was OK, so building another out of discrete components doesn't really help.
ie: You've replaced a good part with another good part. (Assuming you didn't make a mistake doing so) Therefore the fault is elsewhere.

I am sorry for any misunderstanding, the IG04080 has been dead from the inception of this thread.

[pulsed_power]

Each and every component within the unit has been thoroughly tested. The technician that performed the test did not understand how to test the opto-coupler and the IG04080. Upon receiving the unit back from the technician, I was able to find support on the forums that located the test procedures. The opto-coupler tested fine but the IG04080 failed. Thus the journey began here for a replacement.

[Kim Christensen]

Doesn't this point to problems elsewhere in the power supply? Because you tested the IG04080 at the beginning of this thread and it was OK, so building another out of discrete components doesn't really help.
ie: You've replaced a good part with another good part. (Assuming you didn't make a mistake doing so) Therefore the fault is elsewhere.

I am sorry for any misunderstanding, the IG04080 has been dead from the inception of this thread.

What were you testing in the comment that I linked?
Curious as to which part of the test that the IG04080 failed... Was it a dead short, open, etc?

[pulsed_power]

Doesn't this point to problems elsewhere in the power supply? Because you tested the IG04080 at the beginning of this thread and it was OK, so building another out of discrete components doesn't really help.
ie: You've replaced a good part with another good part. (Assuming you didn't make a mistake doing so) Therefore the fault is elsewhere.

I am sorry for any misunderstanding, the IG04080 has been dead from the inception of this thread.

What were you testing in the comment that I linked?
Curious as to which part of the test that the IG04080 failed... Was it a dead short, open, etc?

Yamaha produced four different models of amplifiers that used this IG04080. I don't know the production amount of these units but I think it would be safe to say the number is in the thousands. The IG04080 is the only part within the units that can't be sourced to make repairs to these units. These four models are considered some of the best units that were made in the years of production. Therefore I don't think I am the only person that would like to find a solution.

[Kim Christensen]

Yamaha produced four different models of amplifiers that used this IG04080. I don't know the production amount of these units but I think it would be safe to say the number is in the thousands. The IG04080 is the only part within the units that can't be sourced to make repairs to these units. These four models are considered some of the best units that were made in the years of production. Therefore I don't think I am the only person that would like to find a solution.

I see... You want to create a discrete module to replace a IG04080 for others.

So I assume you have a working IG04080 that functions in the amplifier you are using for your tests? (You say you don't. But then what did you test at the beginning? You still haven't answered that question)
ie: Your current situation should be this: You put a working IG04080 into the Yamaha amplifier and it works fine. Then you substitute your breadboarded circuit and it doesn't work.
The root of my question is: "How do we know if your Yamaha amplifier would work if a functional IG04080 was installed in it?"
Without knowing with 100% certainty that this would be the case, trying to design, build, & test a discrete IG04080 using this amplifier would be a foolish errand. Doesn't matter if someone checked every component or not: You'd have no idea if the reassembled amplifier is functional at all.

Just trying to do some basic troubleshooting so we're not running in circles. Your IG04080 looks OK to me. See your highlighted quote below:

Test procedure:

I used the following procedure to test the special Yamaha Silicon Bilateral Switch IG04080. It must be removed from the circuit board to test it. Use a bench power supply set at 12v, and put a 10k to 20k resistor in series with the positive output of the supply. (Assume you select a 12k resistor in series with the 12v supply)

1) Connect the cold end of the 12k resistor to pins T1 and G on the IG04080. Connect the T2 pin to GND on the bench supply. With a voltmeter from T1/G to T2, it should show around 8v. Mine was 8.00v. I had expected about 9v, but 8v is better, and it is what it is.

2) Reverse the connection of T1/G and T2. Connect the 12k resistor to T2 and ground T1/G. Again it should read 8v across the IG04080. Mine was 7.99V. This is amazingly close matching by the way.

3) Connect the cold end of the 12k resistor to the T1 pin alone. Leave the G pin open circuit. Connect T2 to GND. Measure the voltage across T1 to T2. I expected it to be around 2.1v. Mine was around 1.3v.

4) Reverse the connection of T1 and T2 leaving G open again. The result should be essentially the same as step 3 above.

This procedure tests the internal diode bridge and Zener regulator first. Then tests the internal "SCR" breakover voltage. I believe that if the device under test passes this procedure, that it can be deemed to be OK.

[pulsed_power]

The opto-coupler tested fine but the IG04080 failed. Thus the journey began here for a replacement.

The purpose of showing the test procedure was for the purpose defining the operating parameter's.

My IG04080 is dead and I don't have a replacement, so yes this does create a handicap.

[pulsed_power]

Without knowing with 100% certainty that this would be the case

The only thing in life that is 100% certain is Death and Taxes

[pulsed_power]

I see... You want to create a discrete module to replace a IG04080 for others.

I am in need to get my unit back up and running and I think many others could benefit from this. Is that a bad thing?

[Kim Christensen]

The purpose of showing the test procedure was for the purpose defining the operating parameter's.

So when you wrote "I" in the sentence, "I used the following procedure to test the special Yamaha Silicon Bilateral Switch IG04080" and then said, "Mine was 8.00v", etc.. You were quoting someone else? A copy/paste from another website or something?
That is the part I find confusing.

[pulsed_power]

Info to date

[pulsed_power]

The purpose of showing the test procedure was for the purpose defining the operating parameter's.

So when you wrote "I" in the sentence, "I used the following procedure to test the special Yamaha Silicon Bilateral Switch IG04080" and then said, "Mine was 8.00v", etc.. You were quoting someone else? A copy/paste from another website or something?
That is the part I find confusing.

100% correct, once again sorry for any confusion

[Kim Christensen]

100% correct, once again sorry for any confusion

Ok, no problem. Now that we are on the same page, what are you doing with the red alligator jumper clips here? It looks like you are shorting out the LED on the opto-coupler. (TR606):

[pulsed_power]

See below for explanation of jumper

[pulsed_power]

ACV at Primary of Transformer V1 & GY

[pulsed_power]

@120vac output on the variac the measured ACV at GY TI with DVM is 5.35vac

[Kim Christensen]

@120vac output on the variac the measured ACV at GY TI with DVM is 5.35vac

Looks like it passes the test. Congrats!

[pulsed_power]

I don't know if this is within your scope of knowledge, but I am still having a issue:

I am getting the proper 5.5vac at GY and VI
But at Orange and Blue I am getting 1.7vac, I think this should be 14vac to get 14vdc out of the rectifier

[Kim Christensen]

I am getting the proper 5.5vac at GY and VI
But at Orange and Blue I am getting 1.7vac, I think this should be 14vac to get 14vdc out of the rectifier

Is this with the jumper still installed between TP1 and J605? I would guess that to be normal with the jumper installed. Remove that jumper and turn the power back on and see if you get 14Vdc out of the rectifier.

[pulsed_power]

@ Blue and Orange with fuses removed and jumper removed
With DVM 1.7vac

[pulsed_power]

I had another person look at this Orange Blue connection on his unit, this is what he found

[Kim Christensen]

@ Blue and Orange with fuses removed and jumper removed
With DVM 1.7vac

I assume it is the same with the fuses installed...

Check the +B and -B voltages on the "Control Circuit 1" PCB. Since that's the PCB which the regulates the voltages.
Also, check the DC voltage across R623. This will tell us how much current is flowing through the LED of TR606... The more current that flows through the OPTO, the more AC voltage you should see on the Blue and Orange transformer wires. A voltage of zero across R623 would explain the low output. Then we'd just have to figure out why TR603, etc is not turning on.

[pulsed_power]

@ Blue and Orange with fuses removed and jumper removed
With DVM 1.7vac

I assume it is the same with the fuses installed...

Check the +B and -B voltages on the "Control Circuit 1" PCB. Since that's the PCB which the regulates the voltages.
Also, check the DC voltage across R623. This will tell us how much current is flowing through the LED of TR606... The more current that flows through the OPTO, the more AC voltage you should see on the Blue and Orange transformer wires. A voltage of zero across R623 would explain the low output. Then we'd just have to figure out why TR603, etc is not turning on.

Measure VDC between B+ and B- or Ground to B+ and then B-?

[Kim Christensen]

Measure VDC between B+ and B- or Ground to B+ and then B-?

Between  B+ and B- seems more logical since the "Voltage variation detector circuit" doesn't appear to reference ground at all. (Doesn't hurt to know what B+ and B- are when referenced to ground. Plus, the voltages on the diagram are ground referenced.) Also measure between RS and B+ as well since that seems to be the voltage feedback path.

[pulsed_power]

Measure VDC between B+ and B- or Ground to B+ and then B-?

Between  B+ and B- seems more logical since the "Voltage variation detector circuit" doesn't appear to reference ground at all. (Doesn't hurt to know what B+ and B- are when referenced to ground. Plus, the voltages on the diagram are ground referenced.) Also measure between RS and B+ as well since that seems to be the voltage feedback path.

B+ and B- between = 0vdc
B+ to ground = 0vdc
B- to ground - 0vdc

Section B of the test is very confusing at best. In addition TR802 doesn't exist.

[Kim Christensen]

Well, that's not good at all. Probably an issue in the "rectification circuit" because it looks like B+ and B- come from there. Can you provide a higher resolution of the schematic section shown below: