My findings….
From ground terminal to pins…
Ground to pin 1 = 82 to 86 ohms
Ground to pin 2 = All over the place
Ground to pin 3 = 0.3 to 1.0 ohms
How am suppose to check pins to the heat sink? The heat sink is anodizes and will not conduct electricity, right? The board is out from the case right now. Do you want me to clamp it down?
From ground terminal to pins…
Ground to pin 1 = 82 to 86 ohms
Ground to pin 2 = All over the place
Ground to pin 3 = 0.3 to 1.0 ohms
How am suppose to check pins to the heat sink? The heat sink is anodizes and will not conduct electricity, right? The board is out from the case right now. Do you want me to clamp it down?
Those are the power supply transistors. Those readings look reasonable.
Check the output transistors but instead of placing one probe on the sink, place it on the ground terminal of the amp. No need to clamp it back down unless you need to apply power to it.
Earlier you measured from the outputs to the sink and got 1 ohm. Where was the probe that was not on the leg of the transistor?
The heatsink anodizing can get scratched and will no longer act as an insulator.
Check the output transistors but instead of placing one probe on the sink, place it on the ground terminal of the amp. No need to clamp it back down unless you need to apply power to it.
Earlier you measured from the outputs to the sink and got 1 ohm. Where was the probe that was not on the leg of the transistor?
The heatsink anodizing can get scratched and will no longer act as an insulator.
My findings….
From ground terminal to pins (output transistors)…
Ground to pin 1 = -0.5 to 1 ohms
Ground to pin 2 = 722 ohms…. The last 2 on each side are different 0.5 and 82 ohms & 0.5 and -80 ohms
Ground to pin 3 = -0.7 to 0.5 ohms execpt the last 2 on each side. 0.5 and -0.7 & 1.1 and -0.5 ohms
Earlier you measured from the outputs to the sink and got 1 ohm. Where was the probe that was not on the leg of the transistor?...on the clamp.
From ground terminal to pins (output transistors)…
Ground to pin 1 = -0.5 to 1 ohms
Ground to pin 2 = 722 ohms…. The last 2 on each side are different 0.5 and 82 ohms & 0.5 and -80 ohms
Ground to pin 3 = -0.7 to 0.5 ohms execpt the last 2 on each side. 0.5 and -0.7 & 1.1 and -0.5 ohms
Earlier you measured from the outputs to the sink and got 1 ohm. Where was the probe that was not on the leg of the transistor?...on the clamp.
Last edited:
Nothing appears shorted there.
Desolder the 4 wires shown on the attached photo. You'll have to apply additional solder to the bottom side of the board. Heat until you can move the wire with the tip of the iron and then pull it free (keep applying heat until it's free). Don't pull on it until the solder is hot enough. The pliers will soak the heat away from the solder.
What is the resistance (meter set to ohms) from the wires (not the board) you desoldered to the B+ terminal of the amp?
Desolder the 4 wires shown on the attached photo. You'll have to apply additional solder to the bottom side of the board. Heat until you can move the wire with the tip of the iron and then pull it free (keep applying heat until it's free). Don't pull on it until the solder is hot enough. The pliers will soak the heat away from the solder.
What is the resistance (meter set to ohms) from the wires (not the board) you desoldered to the B+ terminal of the amp?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.