| cowanrg |
well, i have a broken UCD400AD. im curious if it can be fixed or if i just need a new module.
basically, as long as the amp has power, it puts out 57vdc at the binding posts. thats not good. this happens when the amp is on or off, as long as it has power going to it. thats also the same voltage as the rails.
now, i have 4 of these modules, 2 2-channel amps. all the other modules are just fine and play music just fine with TINY dc offets. ive hooked this one up in place of the others, and it still does the same thing, and the others worked when hooked up in the defective one's place. so, its bad for sure.
so, whats wrong? why is it giving me rail voltage at the binding posts? can i get it fixed, do i just need a new one? |
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| BWRX |
Sure sounds like the high side output FET failed and is shorting the positive rail to the output. Best case scenario is that only the FET is fried. It's more likely that there are more components that went with it though.
Have you probed around the module (disconnected of course) with a multimeter to see if anything else is shorted out?
Any idea what caused the module to fail? |
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| cowanrg |
thanks.
there are no visible problems on the board, it looks just fine. nothing blew (at least spectacularly...). i have NO idea what happened. one day i just tested it and it didnt work.
i havent touched it yet, i didnt have a clue what to look for, other than visible problems. ill check the fets and see whats going on. |
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| BWRX |
Hmm... if nothing blew spectacularly then something else might be wrong with the module. Definitely see if there is anything wrong with the FETs first.
Was the module hooked up to a speaker when it had full rail voltage on the output? Was the speaker damaged? |
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| cowanrg |
| quote: | Originally posted by BWRX
Hmm... if nothing blew spectacularly then something else might be wrong with the module. Definitely see if there is anything wrong with the FETs first.
Was the module hooked up to a speaker when it had full rail voltage on the output? Was the speaker damaged? |
nope, no speaker damage. very very strange. one day, i kicked on the amp (when they were just in the prototype phase), and it made a loud buzzing, i kicked off the amp before anything happened. i thought nothing of it and went back to working on the amps. now that they are being completed, i hooked everything back up again and its bad.
i havent hooked up a speaker to it to see how it reacts to a load, but i really dont want to know :)
the amps were on my main system (with ribbon speakers!) and i used them daily for about a month or so. one day, i just went to listen to some music (as i did several times a day), and it just started buzzing when i turned it on. nothing seemingly changed. i also use power conditioners and surge protectors on all my stuff. |
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| Tekko |
| Theres your problem, no wonder it failed if you kicked it ;):D |
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| icewall |
How strange!
I have two UcD 400 that shows the exact same behavior as yours. I get the same voltage on speaker outputs as i have on my rails. Similar to you I heard a noice fom the amplifier and shut it down.
I have used my UcD400 for two years, since january they have been driving the woofers in my Orion system.
On my boards I can see something pointing towards heat problems, but I'm not sure.
My question is the same as yours, buy new ones or is it something that can be fixed. Have tryed to mail Hypex for help. |
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| cowanrg |
well, ive been working on getting these done for years now, and im a bit anxious to be totally done with it. ill email hypex today and see what they will do. it broke while it was just sitting there. it was mounted to a heatsink, and in open air (it was just a prototype setup). so, i cant see how mine overheated. it COULD have been a power surge, but use dual furman power conditioners.
ill see what hypex says and post it here, ill even point jan-peter to this thread. |
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| cowanrg |
icewall,
what version is yours? mine is V5. |
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| icewall |
Mine are 2.0
Bottom of board says 06-12-2004
I've had them for alsmost two years. If it was a heat problem I'd like to know so I can correct the heatsinks. :confused: In the next version of amplifier I don't want this to happen again :bawling: I have also mailed Hypex about this but no answer yet. |
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| cowanrg |
| hum, what do your heatsinks look like? |
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| anatech |
Hi icewall,
Just a question here. R23 looks like it's too large for it's pad, different from most of the other soldering. Was it like that or is it a modification?
I don't know much about these switching amps, just analog stuff so anyone else is more than free to jump in here.
-Chris |
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| icewall |
8 mm thick alu, 80 mm height and 200 mm width. Should be enough, I think. Besides they were connected to the bottom of the case, 415x400x5mm thick alu. Industrial heatcompound used in joining them. Due to lack of space they were sitting rather close together.
Which component would be most likley to fail, you think?
anatech:
No modification has been made to the boards. |
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| cowanrg |
yeah, that heatsinking should be just fine.
i measured my fets, and sure enough, they are shorted. i emailed hypex, hopefully they will get back to me soon. ive bought 9 of these from them and need to order at least 4 more. |
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| icewall |
Well then I'm lucky, I have only two of them...
But the fets shortening? Yours are brand new I guess?
I can accept if mine blew up due to something :smash: , but brand new ones??? |
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| Jorrit |
| quote: | Originally posted by icewall
Well then I'm lucky, I have only two of them...
But the fets shortening? Yours are brand new I guess?
I can accept if mine blew up due to something :smash: , but brand new ones??? |
Hi Icewall,
I don't know what caused your modules to fail at this point. I suggest you send both modules back to us since we're anxious to find out what happenend. The day the modules are received two brand new modules will leave for Sweden ;)
In your email you express your worries about other people having the same problems with their modules. I can assure you that there's no reason to panic when one or two problems with the UcD400 are reported in this forum. We're talking about thousands of sold modules here.
Cheers,
Jorrit
www.hypex.nl |
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| icewall |
You can consider them on their way...
No, I don't have any panic about that. Sorry if it's sound like that. I just found it a bit amusing/odd that my modules and cowanrg:s gave up at the same time. ;)
I have 4 UcD 180:s also, and I'm wery pleased with them as I have been with the 400:s. They are great, affordable and easy to work with. So far the best amplifier purcase I have made... :) |
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| cowanrg |
they had a timer in them!
it is strange that mine died seemingly randomly. one day they just stopped working. i wasnt even listening to them (nor where they on) when they died. i just turned it on and it was like that. oh well.
in my email, i wasnt trying to imply a trend, i was just saying i have many of these modules because i wanted you to know that i have successfully used them before, and am not new to them. if all of them had blown, thats another story! i was just saying that it IS a rare case.
do you have a specific address, or the will the one from your site work? |
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| trango |
Hi,
This morning I discovered that one of my 400AD modules is broken and feed 60V DC into the binding post. Fortunately, the speakers were some crappy test speakers and not my Linkwitz Orion system which I usually use.
Finding this thread, I understand that this has happend to a few others on this forum and I would like to know if the reason for this behavior has been clarified?
The modules has been working perfectly for quite a long time and I also have a four channel 180AD amp that works very nice so I don't think my assembly that has caused the malfunction - this is all similar to the other stories in this thread.
Intriguingly, the blue led of the broken module shines!?
It's a dual mono system composed of a soft start, 2*(2*40) VAC, rectifiers, and caps of 28000 uF in total (divided into 4* (1000+4700+1000+100+1 uF).
Their usual load is the woofers of the Orion system (similar as icewall), 2pcs of Peerless XLS10 for each 400AD module. I think this is a quite difficult load with a rather low impedance ( down to 2 Ohms if I rember correctely). Could a low impedance be the reason for the problem?
Any other ideas?
/Trango |
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| icewall |
Unfortunatley my amp has also broken again!
Thanks to jorrit and hypex I had my modules back in almost no time, mounted them in a new box, with better cooling. Everything else the same, and after playing just for a few hours they blew up again. :confused: The same symptom again.
I have the same setup as trango, some minor changes in capacitors but it shouldn't matter. Everything has worked fine with the Orion woofers and the two UcD400:s drivinge them for over a year, i was not playing at very loud volumes or anyting else strange?
I'm pussled??? What do i have to change to get it working properly?? |
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| guyv |
Probably not relevant to the discussion but I find 6.5V on the output on my two UcD180s (with nothing connected to the input) when the /on wire is disconnected. The UcD400 has only 0.1V. That concerned me but when I connected the /on wire to the ground to turn-on the UcDs then the output voltage is zero as expected.
I guess the DC offset when /on is floating has no power behind it and so is no dangerous.
It is amazing that through luck people did not get expensive speakers damaged when the UcDs failed.
Guy |
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| cowanrg |
| quote: | Originally posted by guyv
Probably not relevant to the discussion but I find 6.5V on the output on my two UcD180s (with nothing connected to the input) when the /on wire is disconnected. The UcD400 has only 0.1V. That concerned me but when I connected the /on wire to the ground to turn-on the UcDs then the output voltage is zero as expected.
I guess the DC offset when /on is floating has no power behind it and so is no dangerous.
It is amazing that through luck people did not get expensive speakers damaged when the UcDs failed.
Guy |
i actually had mine hooked up to ribbon speakers at the time. thank goodness for being quick to turn off the power centers. |
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| mr_push_pull |
| I'd check the power supply if I were you. It sounds to me like some wire (maybe ground?) disconnects intermittently at the power supply side. |
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