I am getting ready to replace all diodes, caps. and resistors. I have owned speakers since 1980s. This issue started very infrequently back then. One speaker cuts out (right channel was main issue), now both channels have the issue. If I turn off the pre-amp or cut power to speaker that cut out, and re-power what was turned off, speaker comes back to life. Speaker quality is great before and after cut out issue. Does anyone have an idea what the issue is? In earlier years I thought it was corrosion/oxidation build up on the high frequency 6 ohm variable resistor center tap. I have not cleaned center tap in years and may try this again. I used a secondary receiver as the source and power and had a cut out issue, I used same interconnects in this test.
Added Schematic and parts list
Interface: MK-121-B. Schematic can be found in Acoustat 2-plus-2 Owners Manual at Steve's - Acoustat 2 plus 2 electrostatic speaker (Download the Acoustat 2 plus 2 owners manual)
Interface: MK-121-B. Schematic can be found in Acoustat 2-plus-2 Owners Manual at Steve's - Acoustat 2 plus 2 electrostatic speaker (Download the Acoustat 2 plus 2 owners manual)
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Thanks for the info!
I did not see anything last time I looked, but I will scan everything again. I have additional info that leads me to think this is not a speaker issue. This issue has always self corrected with a power shut down or playing with connections (no pattern on cause) and occurred very infrequently. Hard to test, but frequency has increased where I can run live tests. I currently think the issue is in the pre-amp exterior power supply module/circuit (vintage museatex PA-6i).
1. During a speaker cut out (L speaker only), test showed no signal was being sent to shut down speaker.
2. During one cut out (L speaker), touching power supply box caused speaker to come back on. Then it cut back out shortly after that.
3. Light / medium taps on power supply box caused speaker to come back on. Then it cut back out.
4. Tapping did not work a second time, but lifting PS box and rotating slightly caused speaker to come back on and system has been stable, no cut outs have occurred.
Power supply is an exterior box connected to the main unit by a four pin connector. I do not have a schematic, but think (hope) the power supply must split power to separate channels before entering main unit. I always power down pre-amp (with rocker switch) before powering down speakers and amp. This could be a bad rocker switch or wire connections since both channels are cutting out at separate times and has increased with use. In the past, it was almost always the right channel that cut out, now left channel is cutting out more often (just recently, last few weeks). I will post what I find when I open the power supply box and test the connector, wire and switch.
I did not see anything last time I looked, but I will scan everything again. I have additional info that leads me to think this is not a speaker issue. This issue has always self corrected with a power shut down or playing with connections (no pattern on cause) and occurred very infrequently. Hard to test, but frequency has increased where I can run live tests. I currently think the issue is in the pre-amp exterior power supply module/circuit (vintage museatex PA-6i).
1. During a speaker cut out (L speaker only), test showed no signal was being sent to shut down speaker.
2. During one cut out (L speaker), touching power supply box caused speaker to come back on. Then it cut back out shortly after that.
3. Light / medium taps on power supply box caused speaker to come back on. Then it cut back out.
4. Tapping did not work a second time, but lifting PS box and rotating slightly caused speaker to come back on and system has been stable, no cut outs have occurred.
Power supply is an exterior box connected to the main unit by a four pin connector. I do not have a schematic, but think (hope) the power supply must split power to separate channels before entering main unit. I always power down pre-amp (with rocker switch) before powering down speakers and amp. This could be a bad rocker switch or wire connections since both channels are cutting out at separate times and has increased with use. In the past, it was almost always the right channel that cut out, now left channel is cutting out more often (just recently, last few weeks). I will post what I find when I open the power supply box and test the connector, wire and switch.
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