Hi there,
Today on the bench I have a Soundcraft UREI model 1601S music mixer.
The symptoms are:
No sound output at the outputs. headphone and main/booth rca both have a slight hum/buzz but no sound. and sometimes intermittently I will get the sound out of the headphone jack but very weak and distorted.
Here's what it does upon startup. The led's upon startup do their little dance and the 2nd channel "VU" leds react to a signal inputted on that channel. No reaction from channel 1. I can activate the Rec buttons and light up for second. Sometimes they act a little crazy and flash on their own, and sometimes the level leds work and other times they don't.
As far as a visible inspection I don't see any of the obvious bulging caps, burns, signs of infestation, etc. Looks clean inside but I have a handle broken off the Phono/Line switch for channel 1 and the crossfader seems a tad loose to me. Reseated a bunch of connectors as well.
So I read on another thread that the DAC and also some IC's are problematic with this unit. Also obtained the unobtainium schematic from here...THANK YOU @R_J ! I was about to give up after talking with customer service/tech support and, apparently Samsung is now overseeing Harmon which ate up Soundcraft. Oh great... I'll move on and save my rant about this for the tavern.
Forgot to mention... I have pushed the reset button on the DSP board and it seems to reboot the system. Same result whether I tap it or hold it down.
OK, so I have started with the SMPS and have these readings on the output vs. chassis ground. Read from CN2 on the smps with everything connected and music playing thru channel 2.
PIN 1 +v2 = 9.46vdc
PIN 2 DGND? = 0
PIN 3 +V1 = 16.46vdc
PIN 4,5 AGND= 0
PIN 6 -V1 = -16.97vdc
So I would say the voltage reading are a tad high but since it they are within 10-15% I think I'll keep going but will need a little direction please as the schematic is one of those formats that I just can't wrap my head around. I've attached the schematic from R_J in the other 1601S post.
p.s.
I have DVM's, a 2ch Scope and signal generator at my disposal.
Thanks,
Eric
Today on the bench I have a Soundcraft UREI model 1601S music mixer.
The symptoms are:
No sound output at the outputs. headphone and main/booth rca both have a slight hum/buzz but no sound. and sometimes intermittently I will get the sound out of the headphone jack but very weak and distorted.
Here's what it does upon startup. The led's upon startup do their little dance and the 2nd channel "VU" leds react to a signal inputted on that channel. No reaction from channel 1. I can activate the Rec buttons and light up for second. Sometimes they act a little crazy and flash on their own, and sometimes the level leds work and other times they don't.
As far as a visible inspection I don't see any of the obvious bulging caps, burns, signs of infestation, etc. Looks clean inside but I have a handle broken off the Phono/Line switch for channel 1 and the crossfader seems a tad loose to me. Reseated a bunch of connectors as well.
So I read on another thread that the DAC and also some IC's are problematic with this unit. Also obtained the unobtainium schematic from here...THANK YOU @R_J ! I was about to give up after talking with customer service/tech support and, apparently Samsung is now overseeing Harmon which ate up Soundcraft. Oh great... I'll move on and save my rant about this for the tavern.
Forgot to mention... I have pushed the reset button on the DSP board and it seems to reboot the system. Same result whether I tap it or hold it down.
OK, so I have started with the SMPS and have these readings on the output vs. chassis ground. Read from CN2 on the smps with everything connected and music playing thru channel 2.
PIN 1 +v2 = 9.46vdc
PIN 2 DGND? = 0
PIN 3 +V1 = 16.46vdc
PIN 4,5 AGND= 0
PIN 6 -V1 = -16.97vdc
So I would say the voltage reading are a tad high but since it they are within 10-15% I think I'll keep going but will need a little direction please as the schematic is one of those formats that I just can't wrap my head around. I've attached the schematic from R_J in the other 1601S post.
p.s.
I have DVM's, a 2ch Scope and signal generator at my disposal.
Thanks,
Eric
