Hey guys
I currently have a set of power supplies and crossovers from a Martin Logan Quest that I'm wanting to find a way to properly test prior to hooking them up to anything. The amplifier hooked up to the speakers either blew up in a very had way or was exposed to some kind of power surge. The power supplies look ok other than one has a blown resistor near the bottom.
If the ESL power supply board and main transformer are still ok I should be able to save this speaker. Any help is appreciated as this whole electronics repair hobby is pretty new to me, no shops will touch this stuff so I have to do it myself.
Power supply 1 has a blown resistor inline with the speaker signal wires that turn the power supply on when you play sound.
#2 looks fine, no physical damage, but must be tested
I currently have a set of power supplies and crossovers from a Martin Logan Quest that I'm wanting to find a way to properly test prior to hooking them up to anything. The amplifier hooked up to the speakers either blew up in a very had way or was exposed to some kind of power surge. The power supplies look ok other than one has a blown resistor near the bottom.
If the ESL power supply board and main transformer are still ok I should be able to save this speaker. Any help is appreciated as this whole electronics repair hobby is pretty new to me, no shops will touch this stuff so I have to do it myself.
Power supply 1 has a blown resistor inline with the speaker signal wires that turn the power supply on when you play sound.
#2 looks fine, no physical damage, but must be tested
If you determine that the board without the burnt resistor is ok,
then test both speakers with the "good" board to be sure the speakers are otherwise ok.
If the speakers are ok, then only the bad board needs repair.
Test all the resistors, diodes, and the two 100uF 10V capacitors, that are near the burned resistor.
then test both speakers with the "good" board to be sure the speakers are otherwise ok.
If the speakers are ok, then only the bad board needs repair.
Test all the resistors, diodes, and the two 100uF 10V capacitors, that are near the burned resistor.
your fuse holder is broken in #2, that will drive you nuts with intermittent connections.
Sheldon
Sheldon
Martin Logan got back to me with how to check the bias voltage so once I pick up the parts I think I need I should have no issues determining if it's good or bad.
Thanks for the help and information guys.
Yeah I did that by accident, the metal is super brittle so I'll replace them most likely.
Thanks for the help and information guys.
Guys, any idea how long it takes for the HV bias to bleed off in a QUAD 989 after disconnecting the mains?
I've got some work to do in the electronics compartment, I'm a bit jittery ...
Jan
I've got some work to do in the electronics compartment, I'm a bit jittery ...
Jan
There are no bleeder resistors to fix that discharge time. The factors are panel cleanness and humidity. Overnight should certainly do it in my experience.
Sheldon