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Vintage Synth Repair

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Ensoniq ESQ1 low output

Ensoniq ESQ1 low output

2008-03-23 by Scott Davies

I picked up an Ensoniq ESQ1 the other day that has very low output in 
the left/mono channel and no output from the right channel. The ESQ1 
Hacker page suggests that replacing the capacitors in the power supply 
could cure many problems. The internal battery warning comes on after 
power up, although it still has enough juice to hold patches so far
(after it was initialized).  Looking for any advice/suggestions on 
troubleshooting this.  Thanks, Scott

Re: [vintagesynthrepair] Ensoniq ESQ1 low output

2008-03-23 by Antoine DeschĂȘnes

Replacing the power supply caps can't do any harm, try it, but if it 
still doesn't work, look for bad solder joints, shorted 1/4 jacks, poor 
connections, etc.

It's possibly PSU related though : The distorted sound could be the 
audio signal passing through an unpowered opamp, and no sound from the 
right channel could be caused by the L+R merging components for the mono 
output (when nothing is plugged in R) not receiving power.

But at the same time, it could be caused by damaged output jacks. There 
would be a bit of audio signal leaking from the shorted signal.

Scott Davies a \ufffdcrit :
Show quoted textHide quoted text
> I picked up an Ensoniq ESQ1 the other day that has very low output in 
> the left/mono channel and no output from the right channel. The ESQ1 
> Hacker page suggests that replacing the capacitors in the power supply 
> could cure many problems. The internal battery warning comes on after 
> power up, although it still has enough juice to hold patches so far
> (after it was initialized).  Looking for any advice/suggestions on 
> troubleshooting this.  Thanks, Scott
>

Re: [vintagesynthrepair] Ensoniq ESQ1 low output

2008-03-23 by scott frye

The ESQ-1 has a "differential" output section to the left/right outputs.

1st thing to check is the +/- 12 Volt DC supply lines on the CEM part pins 12 and 7...the TLO84 part , pins 14 and 7. They should measure from 11.4 to 12.4 VDC.

I would also check for cracks or loose jacks in the output PC board. I see that a LOT in repairs I do

Scott Davies wrote:
Show quoted textHide quoted text
I picked up an Ensoniq ESQ1 the other day that has very low output in
the left/mono channel and no output from the right channel. The ESQ1
Hacker page suggests that replacing the capacitors in the power supply
could cure many problems. The internal battery warning comes on after
power up, although it still has enough juice to hold patches so far
(after it was initialized). Looking for any advice/suggestions on
troubleshooting this. Thanks, Scott




Scott Frye
AudioFixation
Consumer / Pro Audio Repair
Southern VT

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