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As you said :"I have two 2k resistors, an 8.2k, and a 2.2k resistor"
We shall use them for checking.
First thing is to re-solder the diode D8 Leg.
Leave the S1-pin5 wire cut!
100uF caps out of the PCB as it is now.
Build this little circuit, if you don't have a switch, a wire can be fine.
If you have a 2 battery holder with wires it would be perfect,if not ,solder wires directly on the batteries.
Check that the total voltage from the batteries is about 3V,what do you actually get?
Connect it to the circuit, make sure every thing is well isolated including batteries.
Start with the switch open.
Power up the amp(no speakers required).
It should not go into protect mode.
Measure the voltages on R2 and R3.
Now close the switch ,the amp should go into protect mode.
Measure the voltages on R2 and R3.
We shall use them for checking.
First thing is to re-solder the diode D8 Leg.
Leave the S1-pin5 wire cut!
100uF caps out of the PCB as it is now.
Build this little circuit, if you don't have a switch, a wire can be fine.
If you have a 2 battery holder with wires it would be perfect,if not ,solder wires directly on the batteries.
Check that the total voltage from the batteries is about 3V,what do you actually get?
Connect it to the circuit, make sure every thing is well isolated including batteries.
Start with the switch open.
Power up the amp(no speakers required).
It should not go into protect mode.
Measure the voltages on R2 and R3.
Now close the switch ,the amp should go into protect mode.
Measure the voltages on R2 and R3.
Last edited:
The batteries together put out 3.25V.
I connected the curcuit with the switch open and the amp wouldnt turn on, it stood in the protection mode right away until i disconnected the ground. So It going into protection without the switch because as soon as i connect the ground, it goes in protection.
That is not what I'm expecting ,voltage on R3 is too high.
While in protection mode,
please check the following voltages:
The batteries.
Each of the 2 resistors of our Jig (2.2k and 8.2k).
The voltage on the diodes D8-D11(black on the black line of the diode side-the cathode) .
The voltage on R2 and R3.
and voltage on R8.
While in protection mode,
please check the following voltages:
The batteries.
Each of the 2 resistors of our Jig (2.2k and 8.2k).
The voltage on the diodes D8-D11(black on the black line of the diode side-the cathode) .
The voltage on R2 and R3.
and voltage on R8.
Ok, in protection mode with the black probe on speaker ground terminal, i took voltage readings on both sides of each component you asked me to check.
In protection mode i took voltage readings of the batteries on two locations.
Attachments
Rick,
As it is looks like D11 is shorted(1.54-1.51=0.04V.)
Please confirm the voltage on it directly -both probes on it.
Other measurements don't comply with each other for example the voltage on D8 looks "reversed" ,and there are more like that.
Could you please check the voltage on the diodes again.
As it is looks like D11 is shorted(1.54-1.51=0.04V.)
Please confirm the voltage on it directly -both probes on it.
Other measurements don't comply with each other for example the voltage on D8 looks "reversed" ,and there are more like that.
Could you please check the voltage on the diodes again.
Sorry, one side of D11 should have been written 0.54 not 1.54
D8 reading is correct.
I took the Voltage readings of the Diodes and resistors again to make sure.
With Meter set to DC20V, jig connected and amp in protection mode, Negative probe on speaker ground terminal...
D8, Cathode side reads 0.00V
D9, Cathode side reads 1.10V
D10, Cathode side reads 1.10V
D11, Cathode side reads 1.51V
D8, Anode side reads 0.53V
D9, Anode side reads 0.00V
D10, Anode side reads 1.51V
D11, Anode side reads 0.53V
R2 reads 1.51V & other side 0.00V
R3 reads 1.09V & other side 0.53V
R8 reads 0.58V & other side 12.47V
2nd Test, Meter set to DC20V, jig connected, amp in protection mode, both probes on diodes...
D8 reads 0.54V & flipped probes -0.54
D9 reads -1.10V & flipped probes 1.10V
D10 reads 0.41V & flipped probes -0.41V
D11 reads -0.97V & flipped probes 0.97V
3rd Test, I took Ohms reading, meter set to Diode mode, amp off & jig disconnected, negative probe on cathode, and positive probe on anode side...
D8 reads .613 & flipped probes .956
D9 reads .605 & flipped probes 1.271
D10 reads .610 & flipped probes 1.265
D11 reads .620 & flipped probes 1.230
And just so you know, I havent installed Both C6 & C8 Capacitors yet either.
Wow,this is confusing,hard to read.
looks like you have replaced anode and cathode.
this is the notation:
"D9, Cathode side reads 1.10V
D10, Cathode side reads 1.10V"
D9 and D10 have their anode in common not their cathode .
and likwise:
"D8, Anode side reads 0.53V
D11, Anode side reads 0.53V"
D8 and D11 have their cathode in common not their anode .
Also measurement on R3 and D9 do not confirm each other.
No need to flip probes when checking voltage on a diode,
Put the (+)red probe on the anode and the (-) black probe on the cathode.
So,
Voltge on R3=1.09-0.53=0.56, not 1.10v like in post #110
Please re-check the voltages.
no need for resistance checks.
Do you have any diode on hand?
looks like you have replaced anode and cathode.
this is the notation:
"D9, Cathode side reads 1.10V
D10, Cathode side reads 1.10V"
D9 and D10 have their anode in common not their cathode .
and likwise:
"D8, Anode side reads 0.53V
D11, Anode side reads 0.53V"
D8 and D11 have their cathode in common not their anode .
Also measurement on R3 and D9 do not confirm each other.
No need to flip probes when checking voltage on a diode,
Put the (+)red probe on the anode and the (-) black probe on the cathode.
So,
Voltge on R3=1.09-0.53=0.56, not 1.10v like in post #110
Please re-check the voltages.
no need for resistance checks.
Do you have any diode on hand?
All readings are correct on post #111, i didnt write anode or cathode backwards on any of them, thats just how they read according to what im using for the the ground, voltage setting, Ohm setting and position of the probes. I dont know why they seem backwards or the readings dont comfirm, thats why i took readings in 3 different ways thinking maybe it would help you understand why it dont confirm.
Im already confused at what im actually looking for.
I wrote this:
"So,
Voltge on R3=1.09-0.53=0.56, not 1.10v like in post #110"
It should have said post #107.
The voltage on R3 at #107 is too high ,this is what had to be explained.
Now it is ,it was not the voltage on R3 rather the voltage on one of it's legs.
So we have voltage on R3=0.56V and R2=1.54V which is fine.
The diodes voltages are still confusing ,but let's leave it for now.
Now let us change the jig a bit:
Use just one battery instead of two,to produce about 1.5V .
Switch on 8.2K closed(resistor shorted).
Repeat the "protect mode test".
Does it trip?
What are the voltages on R2 and R3( both probes on the resistor)?
Have you got any diode on hand?
"So,
Voltge on R3=1.09-0.53=0.56, not 1.10v like in post #110"
It should have said post #107.
The voltage on R3 at #107 is too high ,this is what had to be explained.
Now it is ,it was not the voltage on R3 rather the voltage on one of it's legs.
So we have voltage on R3=0.56V and R2=1.54V which is fine.
The diodes voltages are still confusing ,but let's leave it for now.
Now let us change the jig a bit:
Use just one battery instead of two,to produce about 1.5V .
Switch on 8.2K closed(resistor shorted).
Repeat the "protect mode test".
Does it trip?
What are the voltages on R2 and R3( both probes on the resistor)?
Have you got any diode on hand?
OK, one battery on the jig reads 1.65V
It doesn't trip though. R2 reads 0.80V & R3 reads 0.20V
I have a pack of diodes.
Attachments
Sorry for the delay, I had something come up.
I shorted the 8.2k resistor. The amp didn't go into protect mode. R2 now reads 1.35V and R3 Reads 0.52V
OK
OK cool, I reversed the jig, It didn't go into protect mode. R2 reads 1.29V & R3 reads 0.50V
OK cool, I reversed the jig, It didn't go into protect mode. R2 reads 1.29V & R3 reads 0.50V
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