Need Help! Master Buss Compressor

[(*steve*)]

The first thing you need to do is to ensure that the two voltage regulators with the metal tabs are not touching. If you can melt the solder joints on the two leads nearest the other regulator you should be able to pivot one of the regulators slightly away from the other one.

I think the next thing you should try is to touch up the solder joints on those two large caps. If you're lucky this will fix the hum problem.

Next use your meter on a volts range to measure the voltage from the common point the capacitors are soldered to to the other side of the caps. You should get roughly the same voltage on each (maybe around 20V?) but one will be negative and the other positive.

If this is OK, then place your meter on an AC range and measure the same places as before. The reading should again be similar, but should be very small.

 

[(*steve*)]

I did notice this after moving from one studio to the next. The problem is that I didnt hook up the compressor until months after the move because we replaced a lot of our hardware with a lot of software plugins. And now that I think about it, I really need to hook it back up to be sure the humming was on both channels and not just one.

If the hum is only on one channel then it's likely NOT the power supply. This is really worth checking before you do anything else.

Also try to distinguish if the hum is the same on both channels, or is both the hum and signal reduced on one channel. This will help a little in pinpointing where the fault may be.

 

[Craig York]

If the hum is only on one channel then it's likely NOT the power supply. This is really worth checking before you do anything else.

Also try to distinguish if the hum is the same on both channels, or is both the hum and signal reduced on one channel. This will help a little in pinpointing where the fault may be.

Ok, will do. I touch base tomorrow and let you know. Thanks again.

 

[Craig York]

Next use your meter on a volts range to measure the voltage from the common point the capacitors are soldered to to the other side of the caps. You should get roughly the same voltage on each (maybe around 20V?) but one will be negative and the other positive.

Can you be a little more clear on this? Im a little confused. What is a "volts range"? Forgive me if this is a stupid question but I am a bit rusty. What I learned in college in slowly coming back to me but I need a little help.

 

[(*steve*)]

Post a picture of your meter and we can explain with reference to the actual item.

 

[dorke]

Very Relevant! Thanks for this.

If the diagram Steve attached is indeed the one of you unit ,a few notes:

1.The big 63V caps are not originals ,they should be 35V(much smaller size).
that explains why thy are mounted on the PS of the board and not the CS.

2.The diagram shows a Bypass Switch(noted below),
I think it may correspond to the In/out one on the front panel.
Does it have any effect on the fault?

 

[Craig York]

If the diagram Steve attached is indeed the one of you unit ,a few notes:

1.The big 63V caps are not originals ,they should be 35V(much smaller size).
that explains why thy are mounted on the PS of the board and not the CS.

2.The diagram shows a Bypass Switch(noted below),
I think it may correspond to the In/out one on the front panel.
Does it have any effect on the fault?


View attachment 24170

This is similar but not the same. The guy that built this created the board. I am trying to get the schematic from him. Just waiting for him to respond to my email.

 

[Craig York]

Post a picture of your meter and we can explain with reference to the actual item.

I got this one from HomeDepot.

 

[(*steve*)]

I got this one from HomeDepot.

Great!

For voltage measurements (and everything is a voltage measurement unless we specify otherwise):

• Plug the BLACK lead fully into COM (it is always plugged in here)
• Plug the RED lead fully into the connection above and to the right of COM (labelled +VΩ...)
• Turn the meter 1 click to the right of OFF. This is the voltage measuring range.
• The meter defaults to AC. If you are measuring DC (and usually you are) press the SEL button to switch to DC.
• Place the probe tip of the BLACK lead on one point and the probe tip of the RED lead on the other.
• Read the voltage on the display.

Often we will ask for the voltage "between A and B" where A and B are specified points. This means that the BLACK probe tip should be placed on point A and the RED probe tip on point B.

If we ask you to measure the voltage "at point X" in the circuit, we mean that the BLACK probe tip should be placed on the circuit's GROUND REFERENCE and the RED probe tip on point X.

You should hold the probes from behind the raised section to prevent your fingers from slipping down the probes. Also be very careful not to move the probes while you glance over at the meter. If it's tricky, either get someone to read the meter for you, or use the "hold" function on your meter (I'll let you read about that in the instructions).

Incidentally, the GROUND REFERENCE for this device is the point where two leads from those large capacitors join, or anywhere along the trace that connects them.

 

[Craig York]

Great!

For voltage measurements (and everything is a voltage measurement unless we specify otherwise):

• Plug the BLACK lead fully into COM (it is always plugged in here)
• Plug the RED lead fully into the connection above and to the right of COM (labelled +VΩ...)
• Turn the meter 1 click to the right of OFF. This is the voltage measuring range.
• The meter defaults to AC. If you are measuring DC (and usually you are) press the SEL button to switch to DC.
• Place the probe tip of the BLACK lead on one point and the probe tip of the RED lead on the other.
• Read the voltage on the display.

Often we will ask for the voltage "between A and B" where A and B are specified points. This means that the BLACK probe tip should be placed on point A and the RED probe tip on point B.

If we ask you to measure the voltage "at point X" in the circuit, we mean that the BLACK probe tip should be placed on the circuit's GROUND REFERENCE and the RED probe tip on point X.

You should hold the probes from behind the raised section to prevent your fingers from slipping down the probes. Also be very careful not to move the probes while you glance over at the meter. If it's tricky, either get someone to read the meter for you, or use the "hold" function on your meter (I'll let you read about that in the instructions).

Incidentally, the GROUND REFERENCE for this device is the point where two leads from those large capacitors join, or anywhere along the trace that connects them.

Good stuff!!!

Ok, so you want me to read the voltage of each capacitor on the board, correct?

 

[(*steve*)]

yes, that's a good start.

measure the voltage on both the AC and the DC range.