Thanks Brandon, I have rustled up a couple of these , now to find the 3300pf ones that seems to be on back order. I am a patient man.
Did you go with the Wimas, or did you find .01-uF, 6kV capacitors available somewhere?
I am the lucky owner of these panels now! Brad is a good friend, in fact I was the one that told him about these in the first place. He told me to come over and listen and I was sold. FINALLY got them set up, but on the second song BOTH speakers blew out there input fuses at the same time. I may have the wiring wrong, as it is definitely faded over the years, but man that first song was lovely. Found one of them had a 4amp slow blow and the other had a no name fast blow. I see the manual calls for 5 amp slow, so I have those on order, arrival tomorrow.
Outputs say red, white, and blue, however the wires look like Pale Blue, Yellow, and Orange. To me, in order, that means they are Blue, White, and Red, but I did not trace to find out. On the first song I smelled the smell of heat. One of the power resistors, the one by the caps actually, was getting quite toasty. Not sure why, or if this contributed to the failure of the fuses. I guess I did not expect them to die TOGETHER.
Driving with a Yamaha preamp, Adcom GFA565 amps, and a DSD via optical for the input. Sat a pair of Klipsch R-14m's on top to verify it is not my amps, and it is not, they sound great. So, maybe those fuses were on the way out? Maybe I wired wrong? I will pull the back panels off tonight to see.
Any other advice? (other than get them out of the room they are in.. It is only 10x12ft, so they are a BIT close to each other, but you work with what you have). I am a content creator as well, so they will be the subject of some mods, including risers, built to match the current stands via 3D Scanning and 3D Printing (because that is what I do, so why not..) As well as custom sound deadening for the room, but not sure what else I should be looking into to make them SING!
-Grant
Grant - remind me which model speaker you have?
I think you've interpreted the wire color codes correctly - those colors can fade after so many years. In any case, mixing up these wires shouldn't result in fuse blowing. The fuse blowing could be caused by many things, and it would help to know which resistor is getting very hot. There are (2) resistors (most models use 50-kohm, 50-watt) on the printed circuit board. There is another 1-ohm, 25-watt resistor associated with the low frequency transformer. And finally, there is 25-watt resistor associated with the high frequency transformer. The value of that resistor will vary depending on the model/update status of your speakers. Under normal listening levels and conditions, none of these resistors should be getting hot enough to stink. If the interfaces are very dusty, you might be smelling the dust burning, but that's not likely. Kind of like when you turn on an electric heater after not using it for a while.
And in speaking of "normal conditions", I mean that your amp is not oscillating or producing significant DC offset. Your amp may work fine on other speakers, but perhaps not so much the difficult load of the Acoustat. I also recommend temporarily using a smaller value fast blow fuse, say about 3A, and test only at moderate levels. The 5-amp slow-blow fuses offer protection only in case of catastrophic failure. If there is something wrong, you don't want to cause any collateral damage to either speaker or amp. Once your problem is solved, then you can go to the 5-amp slow-blow. Generally speaking, use the minimum value of slow-blow fuse that will not blow under normal listening levels. That value will depend on the size of the speaker, the power of your amplifier, and your listening habits.
Let me know how else I may help.
I think you've interpreted the wire color codes correctly - those colors can fade after so many years. In any case, mixing up these wires shouldn't result in fuse blowing. The fuse blowing could be caused by many things, and it would help to know which resistor is getting very hot. There are (2) resistors (most models use 50-kohm, 50-watt) on the printed circuit board. There is another 1-ohm, 25-watt resistor associated with the low frequency transformer. And finally, there is 25-watt resistor associated with the high frequency transformer. The value of that resistor will vary depending on the model/update status of your speakers. Under normal listening levels and conditions, none of these resistors should be getting hot enough to stink. If the interfaces are very dusty, you might be smelling the dust burning, but that's not likely. Kind of like when you turn on an electric heater after not using it for a while.
And in speaking of "normal conditions", I mean that your amp is not oscillating or producing significant DC offset. Your amp may work fine on other speakers, but perhaps not so much the difficult load of the Acoustat. I also recommend temporarily using a smaller value fast blow fuse, say about 3A, and test only at moderate levels. The 5-amp slow-blow fuses offer protection only in case of catastrophic failure. If there is something wrong, you don't want to cause any collateral damage to either speaker or amp. Once your problem is solved, then you can go to the 5-amp slow-blow. Generally speaking, use the minimum value of slow-blow fuse that will not blow under normal listening levels. That value will depend on the size of the speaker, the power of your amplifier, and your listening habits.
Let me know how else I may help.
Monitor 4s from user Brad225 who is local, and a friend 
Yeah it had a bit of the warm dust smell, but Brad did a good job of cleaning out the boards. It was the resistor close to some caps near the back removable fuse on the board. (Photos linked below of a top down as well as the resistor in question)
The speakers sounded amazing before the fuse blew, but the fuses in it, one was 4 amp, the other was a no name. I only ordered 5 amp slows though and they arrived today. I did just order a kit of fast blows as well.
Amps were a pair of Adcom GFA 565's which have worked amazingly well for years. They have WAY more than enough power, but what I find is that I have to turn the preamp up MUCH louder than I thought to get decent volume out of the panels vs normal speakers, but I did chock that up to inefficiencies in the system.
https://photos.app.goo.gl/QwoHDd8i5hnCWUuG7
Yeah it had a bit of the warm dust smell, but Brad did a good job of cleaning out the boards. It was the resistor close to some caps near the back removable fuse on the board. (Photos linked below of a top down as well as the resistor in question)
The speakers sounded amazing before the fuse blew, but the fuses in it, one was 4 amp, the other was a no name. I only ordered 5 amp slows though and they arrived today. I did just order a kit of fast blows as well.
Amps were a pair of Adcom GFA 565's which have worked amazingly well for years. They have WAY more than enough power, but what I find is that I have to turn the preamp up MUCH louder than I thought to get decent volume out of the panels vs normal speakers, but I did chock that up to inefficiencies in the system.
https://photos.app.goo.gl/QwoHDd8i5hnCWUuG7
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I would insist on you getting rid of the three-prong banana plug and those extra lengths of wire. That wire doesn't look high voltage rated. Connect the panel wires directly to the corresponding terminals on the PC board. I'm not saying this is the source of your problem...but it could be! This is a seriously bad arrangement for high voltage connections, especially with those banana prongs hanging in the open where they could contact another surface. The connections carry up to 5000-volt signals, which can easily arc to other surfaces even if those surfaces are not touching. The more I think about it, the more I "like" this as the source of your fuse blowing. No kidding, fix this before proceeding.
BTW, that banana plug is a holdover from the original MK-121-1 interface (or servocharge amplifier) originally supplied with the Monitor 4, either of which used a banana plug connection. For your MK-121-2 interface, wires should be connected directly to the PC board. For Monitor 4, you should have 4 red wires - those go to the center red pin jack. The 4 blue wires should be connected to the blue thumbscrew terminal, and the 4 white wires should be connected to the white thumbscrew terminal.
BTW, that banana plug is a holdover from the original MK-121-1 interface (or servocharge amplifier) originally supplied with the Monitor 4, either of which used a banana plug connection. For your MK-121-2 interface, wires should be connected directly to the PC board. For Monitor 4, you should have 4 red wires - those go to the center red pin jack. The 4 blue wires should be connected to the blue thumbscrew terminal, and the 4 white wires should be connected to the white thumbscrew terminal.
The bananas are not electrified, I have verified this before doing anything with the speakers, no wires go into them. This is how they were when Brad got them too. I was not aware it was 5kv, you can definitely get some corona on that, but no ozone smell or corona noise. (I am very sensitive to it, using CO2 lasers, the ozone smell is an early indication of tube failure) My plan was to make a box with some female bananas on them, re do the wiring off the PCB with some nice shielded stuff and use the box that I build as a passthrough allowing for disconnection easily. I do product development, 3d printing, and 3d scanning professionally so I have materials that are ESD safe and fire retardant should I need it to make these boxed out of. The wires from the speakers are not long enough to connect directly into the pcb without stressing them HARD. That is why I was thinking to have an interface box to keep wiring easier.
Hilariously I do have quite a bit of 24kv rated wire here laying around form the last time I changed my laser tube. I can easily use that for the wire if you think it is necessary.
As for the wiring on the panels, I cannot tell, it has faded so much and a lot of it is just white, into every one of those terminals of the acrylic bricks that appear to just be terminal blocks used to reduce the amount of wires needed. I have to assume they are not correct though, how can I know what is what if the colors are not right, can I trace the wire locations maybe?
If the wires are not long enough to reach the PCB terminals, you can extend from the terminal block on the rear of the speaker. I forgot the Monitor has that feature. Yes, use your HV-rated wire. If you feel the need to trace the wires back to the individual panels for positive identification, the red bias wires will attach to each panel about 1/4 - 1/3 the way up the panel length. The blue wires (rear stator) will come from the short end of the panel, from the rear edge of the panel thickness. Likewise, the white wires (front stator) will come from the short end of the panel, but from the front edge of the panel thickness. See attached sketch.
See #2865. I think these are interfaces to the Model 6 or 8?
https://www.diyaudio.com/community/threads/acoustat-answer-man-is-here.183168/page-144
https://www.diyaudio.com/community/threads/acoustat-answer-man-is-here.183168/page-144
Those are the ones I have. @mraudioguru in fact it's that vertical resistor that's the problem child! That's the one getting spicy.
It looks like the panels are correct, still verifying 100%. All the dang wires are white at this point... And VEEERY dirty.
HV wire in hand. 24 and 40kv. I really would prefer to have some sort of removable system like bananas on it as I definitely won't be in this home forever. Is there a safe way to add it or just de solder later on and stop complaining? There seems to be no removable way to attach to the red pads. I prefer soldering, because less resistance, but I don't know if the connectors will add a ton too..
Fuse kit arrives tomorrow, can do more testing then!
It looks like the panels are correct, still verifying 100%. All the dang wires are white at this point... And VEEERY dirty.
HV wire in hand. 24 and 40kv. I really would prefer to have some sort of removable system like bananas on it as I definitely won't be in this home forever. Is there a safe way to add it or just de solder later on and stop complaining? There seems to be no removable way to attach to the red pads. I prefer soldering, because less resistance, but I don't know if the connectors will add a ton too..
Fuse kit arrives tomorrow, can do more testing then!
Sizing of Fuses for Type MK-121 Interfaces
Another experienced view on sizing Acoustat speaker fuses. (The one on the rear panel of the interface.)
Roy Esposito repairs and upgrades interfaces.
I copied this in 2016. The link below no linger works.
What I have observed over many years now causes me to make the following prudent recommendation.
I would like to encourage everyone with Type MK-121 Interfaces (check serial number label)
to replace the single Audio Fuse with a 4 ampere or 5 ampere FAST BLOW fuse.
If these blow too often, then try 3 ampere or 4 ampere SLOW BLOW. Use the smallest
ampere rating that will hold. 125 volt or 250 volt rating--does not matter.
I suggest Bussman or Littelfuse brands (Home Depot, Lowes)
because cheap fuses can roll off high frequencies.
Reason for this change--back in the 1980's when we designed the interfaces
the factory-specified 5 ampere Slow Blow audio fuse was sufficient protection.
But with today's digital source devices and "faster" amplifier and pre-amplifier
designs, using the originally specified fuse can risk damage to the costly and
scarce Low-Frequency transformer in the MK-121 interface.
I am always interested in buying low frequency transformers of the part
numbers 2008733, 2009064 , or TT121L for use in my service/restoration/upgrade work
for those relatively rare cases where I find a damaged transformer.
Please contact me at acoustat.service.usa@gmail.com
if you have these transformers or even complete MK-121 interfaces to sell,
whether Medallion or Non-Medallion types.
All the Best, Roy
http://www.audiocircuit.com/Forum/Acoustat/5586/Sounds-Like-New
(Dead link.)
======
See also Posts 2,606 and 2,604, and 2,839, by AcoustatAnswerMan.
Another experienced view on sizing Acoustat speaker fuses. (The one on the rear panel of the interface.)
Roy Esposito repairs and upgrades interfaces.
I copied this in 2016. The link below no linger works.
Roy A. Esposito 2015-12-17 14:00
My Dear Friends -What I have observed over many years now causes me to make the following prudent recommendation.
I would like to encourage everyone with Type MK-121 Interfaces (check serial number label)
to replace the single Audio Fuse with a 4 ampere or 5 ampere FAST BLOW fuse.
If these blow too often, then try 3 ampere or 4 ampere SLOW BLOW. Use the smallest
ampere rating that will hold. 125 volt or 250 volt rating--does not matter.
I suggest Bussman or Littelfuse brands (Home Depot, Lowes)
because cheap fuses can roll off high frequencies.
Reason for this change--back in the 1980's when we designed the interfaces
the factory-specified 5 ampere Slow Blow audio fuse was sufficient protection.
But with today's digital source devices and "faster" amplifier and pre-amplifier
designs, using the originally specified fuse can risk damage to the costly and
scarce Low-Frequency transformer in the MK-121 interface.
I am always interested in buying low frequency transformers of the part
numbers 2008733, 2009064 , or TT121L for use in my service/restoration/upgrade work
for those relatively rare cases where I find a damaged transformer.
Please contact me at acoustat.service.usa@gmail.com
if you have these transformers or even complete MK-121 interfaces to sell,
whether Medallion or Non-Medallion types.
All the Best, Roy
http://www.audiocircuit.com/Forum/Acoustat/5586/Sounds-Like-New
(Dead link.)
======
See also Posts 2,606 and 2,604, and 2,839, by AcoustatAnswerMan.
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Ah good to know! The 3a fast blow has been holding great. Unit is ice cold too, nothing getting even remotely warm!
Hello Andy. I have 2 Accustat speakers that I want to upgrade the parts for both. I don't know the model but one has the blue medallion MK 141-B & the other has the MK 2123. First one has 1 panel and is about 6.5 feet tall. The second has 3 panels and is about 6 tall. Thak you
Anthony
I am not a models expert, but that may not be enough data. I suggest you post pictures, overall front and overall back, of each.
I am curious: Do you mean two speakers or two pairs?
The MK141-B are probably the Model One. The MK2123 is probably a Spectra 33 or 3300. I also wonder if you have 2 different speakers or two PAIRS of different speakers? If you have one of each, yeah, that's not gonna work very well...
Pics please.