Those are not as expected. DCV on all terminals of LM319 on the side of the bridged op-amp?
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
1. 0V
2. 0V
3. 0V
4. 2,5V
5. 2.22V
6. 0.3V
7. 0V
8. 4.25V
9. -0,6V
10. -0,6V
11. 4,83V
12. 3,28V
13. 0V
14. 0V
2. 0V
3. 0V
4. 2,5V
5. 2.22V
6. 0.3V
7. 0V
8. 4.25V
9. -0,6V
10. -0,6V
11. 4,83V
12. 3,28V
13. 0V
14. 0V
The 4.83 is low but probably OK.
This is difficult without a scope. Do you have many spare parts on hand?
If you switch your meter to ACV, what readings to you get on pins 4, 5 and 12 of the 319?
This is difficult without a scope. Do you have many spare parts on hand?
If you switch your meter to ACV, what readings to you get on pins 4, 5 and 12 of the 319?
Unfortunately i don't have a scope. What spares do you have on your mind?
Pin 4: 0VAC
Pin 5 0VAC
Pin 12: 0VAC
Pin 4: 0VAC
Pin 5 0VAC
Pin 12: 0VAC
LEDs, assorted resistors, small capacitors... Doing this without a scope is difficult. I'm trying to find some way to make it possible.
I'm only able to find some resistor, that's it. But if you could tell me what i need, i coudl buy some spares and aslo the parts that might me defective on the board to keep troubleshooting
Was the amp powered up and building ~±15v on pins 4 and 8 of the op-amp when you measured all zeros on ACV on the 319?
If you have a different meter, try it.
Meters have a 'bandwidth' like a speaker or amplifier. Outside of that bandwidth, they're unreliable. The frequency at the points you were measuring for ACV were likely near 80kHz. A typical meter will start to lose accuracy above 400Hz. Reading all zeros is unexpected and why I asked about the DCV on pins 4 and 8.
Meters have a 'bandwidth' like a speaker or amplifier. Outside of that bandwidth, they're unreliable. The frequency at the points you were measuring for ACV were likely near 80kHz. A typical meter will start to lose accuracy above 400Hz. Reading all zeros is unexpected and why I asked about the DCV on pins 4 and 8.
Try both of them across the gate and source pads for the PS FETs. Do they both read 0v there as well?
Better? Why wouldn't you default to the better meter?
Better? Why wouldn't you default to the better meter?
They both show 0V (one probe on B-, second on gate/soure) and also show 5.9V if measured between gate/source on ps fets.
Why didn't i default to a better meter? Just remembered that i brought one from work that was jus lying around.
Why didn't i default to a better meter? Just remembered that i brought one from work that was jus lying around.
Unfortunately not. Also im not very familiar to using the oscilloscope, but with good guidance i can learn pretty quickly. Should i buy some cheap usb scope? Like this?https://www.amazon.com/Hantek-Digital-Oszilloskop-Storage-Oscilloscope/dp/B0728HBNDV
Or https://www.fnirsi.com/products/101...VGz7P5LmU0MHodxjtVikL-6My54yVrLBTTGIrrns5RvZe
Or https://www.fnirsi.com/products/101...VGz7P5LmU0MHodxjtVikL-6My54yVrLBTTGIrrns5RvZe
If you're going to buy a USB scope, the OWON VDS1022I (<<< the I is very important as it signifies 'isolated') is the only one I can recommend.
Bear in mind that, even with a scope, we may not be able to get this amp repaired.
This page will get you started. Unless you're using a flash capable browser, the flash graphics won't work. There is non-flash information that will help:
https://www.bcae1.com/oscope.htm
Bear in mind that, even with a scope, we may not be able to get this amp repaired.
This page will get you started. Unless you're using a flash capable browser, the flash graphics won't work. There is non-flash information that will help:
https://www.bcae1.com/oscope.htm
Do you have a local electronics distributor or do you have to order everything?
I'll have to get in the shop to see if I can find a working 500 to try some alternative testing. It may no happen today.
I'll have to get in the shop to see if I can find a working 500 to try some alternative testing. It may no happen today.