Hi, in new on the forum. I have a crown ma12000i from 2010 that needs recapping.
It has 20 teapo 220v 1200uf lh 85°c that i couldnt find anywhere, can someone help me?
Hello @piva.ludovico,
Welcome to the DigiKey forum!
That is an impressive amplifier.
Before joining the DigiKey team I constructed this video that may help answer your question:
Chances are high that DigiKey has the capacitors you are looking for. Here are several options.
Be sure to verify the mechanical size of the capacitor leads as described in the video. Also, capacitors tend to get better (smaller with longer life) over time, You may be able to use improved 105°C devices.
Best wishes,
APDahlen
Hello piva.ludovico,
Welcome to the DigiKey TechForum,
Click here for the closest matches, that we have for a 220V, 1200uf cap.
These are General Purpose Capacitors, and not a specific audio grade, and can also handle up to 105C temperatures.
The closest match for an Audio grade, is 493-16519-ND, but is only rated for 200V.
Please check the datasheets to help verify compatibility to your application.
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Hi, thanks for the answers, i forgot to mention the dimensions of the capacitors, they are approximatly d25*h50mm. I didnt find anything aviable within this sizes.
@APDahlen and yes this amp Is a Beast ahahaha, shakes the roof with 4*18 drivers
Hello @piva.ludovico,
Understood. However, we need to be sure of total number of leads (2 vs 3), style, and the spacing for the capacitors as they contact the PCB.
Also, as I understand the limitation, the capacitors are closely packed into the amplifier. Consequently, the diameter of the replacement is important. Likewise, you may not have any wiggle room in height as the 2U (1.75 x 2) chassis height is a limitation.
Please let us know what you find.
Sincerely,
Aaron
Yes, i’ve taken a couple of photos of the capacitor and distance of the leads with a caliber measurement, don’t know of they are custom ones.
Hello @piva.ludovico,
Now I can see your frustration.
This Chemi-Con ESMM221VSN122MQ50U part appears to be a substitution. Unfortunately, it is a special-order components. Follow the “Available To Order” section on the component’s page.
The challenge is locating a replacement rated at 220 VDC. There are several components with 200 VDC. Unfortunately, I’m hesitant to call these a solution as there may be corner cases when they break down in your amplifier.
Sincerely,
Aaron
P.S. As always, double check my work to make sure I have not misread or misinterpreted your measurements.
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We have in stock a few 250V rated capacitors that will fit in that spot. For example:
Nichicon LGX2E122MELB50
My mistake, I misread the diameter of your cap, that would work if a 30mm capacitor would fit in that spot.
@APDahlen yeah, the output voltage of the amp at clip Is 200v peak so i assume the 200v rated capacitor in the Rail can’t keep up with that. Shame that the equivalent isn’t aviable on a normal order.
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Bad news… I recapped the entire amp and One Little film capacitor exploded when i powered the amp on. What’s your take on this failure?
Im trying to send a couple of pics
Hello @piva.ludovico,
Was this one of the capacitors you replaced?
If yes, it is possible that it was installed backwards. It’s so easy to do. Also, we can’t always trust the PCB. Today I always take pictures before servicing equipment.
If no, I’ve seen that happen too. Especially if the amp has been in storage for a long period of time.
There may be something else wrong with the amplifier. Do you have a schematic? If so, look at the cap’s function and try to identify what could cause it to fail.
I’ll look for your pictures.
Sincerely,
Aaron
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https://drive.google.com/drive/folders/1SD6PjOYXlSPxovGIP8ybX-5TGICu0dtM
These are the pics!
Btw I replaced only the electrolitics in the Main boards so not on the front end board (the Ones thats over the big caps in the left) nor the gate driver boards that are in front of the big coils and near the igbt’s, besides the big 220v 1200uf Ones that are standard type, all the other caps are all low esr, long Life type. All the mountings and the connections were fine. I sent an email to harman for the service manual but i think it’s only for service points.
P.s. the original little caps (so every cap besides the big Ones) were nic components nrss and nrsa, so maybe the new low esr Ones created instability in the circuit? Idk (I’m studying electronic engineering but i’m at the second year)
Oh dear, @piva.ludovico,
The amplifier has some serious damage. It looks like some of the PCB has been vaporized!
It’s nearly impossible to determine cause and effect from the images. All we can say is that the damage is localized to a particular section.
Recommendations:
-
Verify all power semiconductors in the localized are intact.
-
Verify / replace the drivers.
-
Repair the damaged PCB.
-
Replace the damaged capacitor.
-
Slow start the amplifier using a variac with fingers crossed in the hope that the damage has been identified.
While there is great value in troubleshooting and repair, we recognize that this is no place to start. Consider putting the amplifier into storage as you gain experience working on smaller audio amplifier. You may also wish to locate a doner amplifier with an intact PCB.
Sincerely,
Aaron
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