Anyone have a picture of the areas in front of both regulators ?
R215 is burnt
R473,477 begins rca jacks are also burnt
R215 is burnt
R473,477 begins rca jacks are also burnt
I forget but do you happen to know the package size for the 1 ohm resistors ?
And do you know what diode Marked D4 is ? It’s D402 location sits in front of the optocouplers
And do you know what diode Marked D4 is ? It’s D402 location sits in front of the optocouplers
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I think they're 2510s but you can measure them with a dial caliper.
MMBD4148SE if it's marked D4.
MMBD4148SE if it's marked D4.
I replaced the 540’s and all the transistors on the area of the regulators .
Checked all resistors diodes and checked fine .
As soon as I tried powering it up it blew the 1 ohm resistors again R145,146
Any ideas on what to check since it instantly blew the 1 ohm resistors
Checked all resistors diodes and checked fine .
As soon as I tried powering it up it blew the 1 ohm resistors again R145,146
Any ideas on what to check since it instantly blew the 1 ohm resistors
Did you check the transistors for leakage?
If the 1 ohm resistors failed, there could be several problems. There could be too much of a load on the circuit. The regulator could be defective causing full rail to be applied to the circuit.
Was the preamp board plugged in? If so, troubleshoot without that board plugged in.
If the 1 ohm resistors failed, there could be several problems. There could be too much of a load on the circuit. The regulator could be defective causing full rail to be applied to the circuit.
Was the preamp board plugged in? If so, troubleshoot without that board plugged in.
I replaced all of the transistors near the regulators .
I replaced all 3 of the 540’s the 2N5401’s,MMBTA42’sand the 4148 diode along with a couple of resistors .i didn’t have the preamp board plugged into the amp .
And as soon as I touched the remote to the amp it blew the 1 ohm resistors
I replaced all 3 of the 540’s the 2N5401’s,MMBTA42’sand the 4148 diode along with a couple of resistors .i didn’t have the preamp board plugged into the amp .
And as soon as I touched the remote to the amp it blew the 1 ohm resistors
The 2nd photo is just showing the 5 volt regulator that I didn’t change .
The diode was checked for being shorted and leaking off the board and it checked fine
The diode was checked for being shorted and leaking off the board and it checked fine
Rebuild the regulator and instead of installing the 1 ohm resistors, install a 120v incandescent lamp in their place.
Your right it’s dumping full rail voltage across the pads for the 1 ohm resistors .
I hook a light up to it and it lights up bright
Any ideas what to check to fix this issue ?
I hook a light up to it and it lights up bright
Any ideas what to check to fix this issue ?
Is the capacitor under the diode shorted?
When the light is lit, what's the voltage across the capacitor?
When the light is lit, what's the voltage across the capacitor?
Assuming that C114 is out of the circuit (since you can't have 90v across a shorted component), it's likely a 0.1uf if it's parallel with C118.
If it's not in parallel with C118, find the corresponding capacitor on the negative regulator and measure it to see what the value is. It's likely a 0.1uf.
Is it in parallel with C118?
What is the value across C118?
If it's not in parallel with C118, find the corresponding capacitor on the negative regulator and measure it to see what the value is. It's likely a 0.1uf.
Is it in parallel with C118?
What is the value across C118?