dbx 160SL problem/schematic request
Syuda
Posts: 4
Hello
I'm currently servicing a dbx 160SL with a "motorboating" problem on both channels. I've send an email for a service manual request to dbx but got no answer yet.
First, does someone have the service manual with schematics for that beast? I like working on gear with technical docs beside.
I made a quick test with a 1kHz tone :
It seems that the motorboating problem is present at the input stage. The VU-meter when set to "Input" or "Output" display the motorboat sound. All controls are uneffective, and the meter doesn't react when controls are tweaked.
I've also played with the "THRESHOLD" control, which is uneffective too. However, threshold LEDs are working, and correctly display what's happening (motorboat sound peaks light the red LED).
If I set the meter to "Gain Reduction", I can SEE that controls are tweaked but I still can't HEAR any change. The meter display the gain reduction that should take place, as motorboat peaks logically make the needle dancing.
When bypassed, the unit outputs the 1kHz tone without problem.
When the "UNBALANCED" rear switch is on, the motorboat sound level is reduced (seems logical).
Any idea about what I could be? I suspect a PSU problem but I don't know exactly how the 160SL has been designed so I may miss something.
Thanks for your help!
Quentin
I'm currently servicing a dbx 160SL with a "motorboating" problem on both channels. I've send an email for a service manual request to dbx but got no answer yet.
First, does someone have the service manual with schematics for that beast? I like working on gear with technical docs beside.
I made a quick test with a 1kHz tone :
It seems that the motorboating problem is present at the input stage. The VU-meter when set to "Input" or "Output" display the motorboat sound. All controls are uneffective, and the meter doesn't react when controls are tweaked.
I've also played with the "THRESHOLD" control, which is uneffective too. However, threshold LEDs are working, and correctly display what's happening (motorboat sound peaks light the red LED).
If I set the meter to "Gain Reduction", I can SEE that controls are tweaked but I still can't HEAR any change. The meter display the gain reduction that should take place, as motorboat peaks logically make the needle dancing.
When bypassed, the unit outputs the 1kHz tone without problem.
When the "UNBALANCED" rear switch is on, the motorboat sound level is reduced (seems logical).
Any idea about what I could be? I suspect a PSU problem but I don't know exactly how the 160SL has been designed so I may miss something.
Thanks for your help!
Quentin
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