Hi Draco,
I started a new thread so it doesn't get more confusing.
Now, I apologize for my error in determining the problem. I completely missed a very important voltage reading you posted on the last op amp, the TLC2262. That voltage reading is the +5V you should have on pin 8. You measured 2.38v which is wrong. This indicates a power supply problem that has to be evaluated. So, now we have to deal with the wrong voltage and find out why it is happening.
There are a couple of reasons the +5V could be low. One reason is there is a part that is bad causing the voltage to be drawn down. The other is something is wrong in the +5V supply. If it is the supply, then the most common part to go bad is one of the capacitors, probably one of the two used in the voltage doubler stage.
So, now we need to determine just what might be wrong.
To begin with, we need to find the +5 Volt supply.
So, to begin with, we need to find the +5V supply to take a few measurements. We will be looking for VR3. Now, if you set the GS 5 up so the TL062 is in the lower left hand corner, then the VR3 will be closer to the upper right hand corner of the pc board. You will also want to look for D1 and D2 in that general area close to the VR3. There will also be two capacitors, maybe listed as C 15 and C17. These capacitors are part of the doubler stage.
Now, the +5V regulator is VR3 which is a LP2950-5 IC. The IC has 3 legs. The center leg is ground, so any ground will work to connect the black lead of the digital voltmeter. Now measure the other two legs. One should be +5V and the other should be over 10V or so. Let me know what the legs read.
Reg
I started a new thread so it doesn't get more confusing.
Now, I apologize for my error in determining the problem. I completely missed a very important voltage reading you posted on the last op amp, the TLC2262. That voltage reading is the +5V you should have on pin 8. You measured 2.38v which is wrong. This indicates a power supply problem that has to be evaluated. So, now we have to deal with the wrong voltage and find out why it is happening.
There are a couple of reasons the +5V could be low. One reason is there is a part that is bad causing the voltage to be drawn down. The other is something is wrong in the +5V supply. If it is the supply, then the most common part to go bad is one of the capacitors, probably one of the two used in the voltage doubler stage.
So, now we need to determine just what might be wrong.
To begin with, we need to find the +5 Volt supply.
So, to begin with, we need to find the +5V supply to take a few measurements. We will be looking for VR3. Now, if you set the GS 5 up so the TL062 is in the lower left hand corner, then the VR3 will be closer to the upper right hand corner of the pc board. You will also want to look for D1 and D2 in that general area close to the VR3. There will also be two capacitors, maybe listed as C 15 and C17. These capacitors are part of the doubler stage.
Now, the +5V regulator is VR3 which is a LP2950-5 IC. The IC has 3 legs. The center leg is ground, so any ground will work to connect the black lead of the digital voltmeter. Now measure the other two legs. One should be +5V and the other should be over 10V or so. Let me know what the legs read.
Reg