The 7815 input pin should connect to "Red output", it's ground to "A", and the output should be +15V measured to "A".
The 7915 input pin should connect to "Blue output", it's ground to "A", and the output should be -15V measured to "A" (meter's black probe to "A", red to the 7915 output).
Don't forget to notice that the pin configuration of the two regulators is not the same, the 7915 ground pin is not in the middle as it is for the 7815.
The 7915 input pin should connect to "Blue output", it's ground to "A", and the output should be -15V measured to "A" (meter's black probe to "A", red to the 7915 output).
Don't forget to notice that the pin configuration of the two regulators is not the same, the 7915 ground pin is not in the middle as it is for the 7815.
I seem to remember Andrew mentioning a while back that some 79 regs need a minimum load of a few milliamps.
Also consider adding diodes (reverse polarity) between each 15 volt reg output and ground and across each reg to prevent a reverse bias situation if the rails rise at slightly different rates. That can cause a latch up on switch on.
Also consider adding diodes (reverse polarity) between each 15 volt reg output and ground and across each reg to prevent a reverse bias situation if the rails rise at slightly different rates. That can cause a latch up on switch on.
tnx alot, without regs i have +/- 34 volts, this ps also have +-34 v output, when i connect both regs +34 and +15 works but other not, why is that so?
What I meant was:
Situation 1: Both Regulators there
Input Voltage of 7815 = ??
Output Voltage of 7815 = ??
Input Voltage of 7915 = ??
Output Voltage of 7915 = ??
Situation 2: 7815 removed
Voltage at Red output = ??
Input Voltage of 7915 = ??
Output Voltage of 7915 = ??
All these voltages measured with respect to node 'A', of course
Situation 1: Both Regulators there
Input Voltage of 7815 = ??
Output Voltage of 7815 = ??
Input Voltage of 7915 = ??
Output Voltage of 7915 = ??
Situation 2: 7815 removed
Voltage at Red output = ??
Input Voltage of 7915 = ??
Output Voltage of 7915 = ??
All these voltages measured with respect to node 'A', of course
Sorry if I dare...
somebody already said it:
you did pay attention to the fact that 78xx and 79xx have a different pinout, right?
78xx has 1=IN, 2=GND, 3=OUT
79xx has 1=GND, 2=IN, 3=OUT
Did you also put the input and output caps caps?
(edit: I just saw your latest post, taht came while I was typing...)
In case there is a heatsink, remember that the tab of the TO-220 package is connected to the center pin. If the two regulators share the heatsink, you want the tabs to be insulated from the heatsink, otherwise the IN of 7915 goes to ground...
Really, don't get mad if I recall thee basics and you had already done it properly
-
somebody already said it:
you did pay attention to the fact that 78xx and 79xx have a different pinout, right?
78xx has 1=IN, 2=GND, 3=OUT
79xx has 1=GND, 2=IN, 3=OUT
Did you also put the input and output caps caps?
(edit: I just saw your latest post, taht came while I was typing...)
In case there is a heatsink, remember that the tab of the TO-220 package is connected to the center pin. If the two regulators share the heatsink, you want the tabs to be insulated from the heatsink, otherwise the IN of 7915 goes to ground...
Really, don't get mad if I recall thee basics and you had already done it properly
-
Last edited:
Sorry if I dare...
somebody already said it:
you did pay attention to the fact that 78xx and 79xx have a different pinout, right?
78xx has 1=IN, 2=GND, 3=OUT
79xx has 1=GND, 2=IN, 3=OUT
Did you also put the input and output caps caps?
(edit: I just saw your latest post, taht came while I was typing...)
In case there is a heatsink, remember that the tab of the TO-220 package is connected to the center pin. If the two regulators share the heatsink, you want the tabs to be insulated from the heatsink, otherwise the IN of 7915 goes to ground...
Really, don't get mad if I recall thee basics and you had already done it properly
-
bro your right, :d ,tnx so much bro it was heatsink, didnt know that,
(F) omg tnx alot
tow days i'm thinking checking... tnx alot (F)
this is your Main Audio Ground to Chassis connection.
It can be used to reduce hum.
It can also be used with a bypass switch to short out the components, i.e. switchable between Disconnecting Network and direct zero ohms.
Or you can make a direct wire link from Main Audio Ground to Chassis.
BUT:
This link may have to pass Fault Current until the Mains fuse ruptures.
That Fault Current can approach and even exceed 1kA. The components MUST survive long enough to guarantee that the fuse ruptures and the arc extinguishes.
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