Digest for sci.electronics.repair@googlegroups.com - 13 updates in 3 topics

jurb6006@gmail.com: Jan 27 05:06PM -0800

This one might not go well. For some reason at work I didn't get their website in a search but the PCs are a little screwed up. I am working on that. Anyway, it has a 180 watt class D amp. Says "icepower" on it. ocme to find out that Icepower is a subsidiary of B&O. The amp board is integrated with the power supply and dubbed 50ASX2.
 
So I find Icepower online and their phone number in Illinois doesn't work. Their website has no "buy parts" or any of that, which is typical here. So I just keep looking ont the net for one and someone has them on eBay. Hundred bucks apiece though. I think the amp might bring $150. Problem is that it already did that and now we gotta either fix it or trade the guy into something else. Or refund, which is really not the idea here.
 
One thing worries me about that board.
 
https://dl.dropboxusercontent.com/u/29948706/50asx2.jpg
 
The board is burned where the red circles are. The one spot apears to be where the power is supplied for the preamp and the other is where I believe is the signal input from the preamp. This leads me to believe that a high potential may have been places across the hot and cold sides, or something. It is also a concern that I might have to fix the preamp, but with any luck that won't be all that bad. Couple of TL072s and all that, doesn't bother me. (I didn't really look at that yet)
 
But y'all with the experience in music stuff and all that, should we just shitcan the thing ? I'm not even completely sure what they're worth. I didn't find any on eBay.
 
Now once the boss starts searching the web for that part he might be able to do better than a hiundred bucks. I have sen him search. So if that happens, fine I probably ifx the preamp.
 
Questions are thus :
 
Does anyone know where to get a deal on that amp/power board ?
 
Is such a design more vulnerable to power fluctuations or big ESD like lightning than a conventional design ? If so, maybe it is better to blow off these class D amps.
 
I think we are going to see more class D in this business because of the allure of the no heat, no heatsink. Not to mention the efficiency. you know I am not afraid of class D amps, but this thing looks like a dman PCI cardd the way it is built. I ain't fixing that. We do not have the equipment for SMDs right now, and it is extremely small. What's more, the chips say "icepower" on them so if any of them fry that is that probably. I think you can actually get "That" ICs, but I am sure about these, plus they are surface mounts.
 
So are the outputs.
 
I don't like this really. If all the class D is going to be built practically unservicable like that I don't know what to do. I didn't learn all this shit to become a board jockey. I know sometimes there is no choice, but still.
 
Maybe we should stock up on tubes and try to gravitate towards that.
 
Whatever. Opinions welcome. Anyone knows where to get a deal on those amp modules I would appreciate it. If you tell me a hundred bucks is a good price, I'll have to consider that.
 
TIA
Phil Allison <pallison49@gmail.com>: Jan 27 06:27PM -0800


> This one might not go well. For some reason at work I didn't get their website in a search but the PCs are a little screwed up. I am working on that. Anyway, it has a 180 watt class D amp. Says "icepower" on it. ocme to find out that Icepower is a subsidiary of B&O. The amp board is integrated with the power supply and dubbed 50ASX2.
 
 
** Here is a link to a supplier for US$99 with free delivery.
 
http://www.classicaudioparts.com/index.php/featured/icepower-170w-amplifier-module-complete-with-power-supply.html
 
Here is another, but a bit more expenisve...
 
http://www.aliexpress.com/item/ICEPOWER-amplifier-circuit-board-module-ICE50ASX2-professional-grade-digital-amplifier-with-power-amplifier-board/1600831618.htm
 
The sort of damage you describe can happen when a speaker lead is mixed up with an instrument lead and plugged into an input - of the same amp or another item.
 
If the sleeve of the jack plug is "hot", input ground tracks get blown open.
 
If the tip is hot, the voltage can find its way onto the DC rails of the preamp and do lotsa damage.
 
That IcePower module is tiny ( 4.3 x 3.1 inches) and lives inside a combo amp - right?
 
 
 
... Phil
 
 
 

 
 
 
 
Phil Allison <pallison49@gmail.com>: Jan 27 06:41PM -0800

Phil Allison wrote:
 
 
> That IcePower module is tiny ( 4.3 x 3.1 inches) and lives inside a combo amp - right?
 
 
** The Chinese made Eden EC210 uses such a module:
 
http://bassmusicianmagazine.com/2013/03/eden-ec210-combo-bass-amplifier-review-by-eric-parsons/
 
 
 
 
.... Phil
jurb6006@gmail.com: Jan 27 06:42PM -0800

>"The sort of damage you describe can happen when a speaker lead is mixed up with >an instrument lead and plugged into an input - of the same amp or another item. "
 
Well I did tell the boss "That amp did not blow itself". If thre guy did that it will be time for some customer education or something.
 
>"If the sleeve of the jack plug is "hot", input ground tracks get blown open. "
 
Understood. Work on those big "BOOM mufuka BOOM mufuka" car amps ? Let the ground lead come a bit loose on that amp and BOOM is kinda the word. When that happens they get a letter printed explaining that if this happens again it will not be covered under warranty. Might have to do this in this case.
 
>"If the tip is hot, the voltage can find its way onto the DC rails of the preamp and do lotsa damage. "
 
Well it could be hot with the output of a six hundred watt amp so yeah. But, it loks like the little fusible that supplies the preamp took a bad hit. should I assume the preamp is shorted ? Probably. Hopefully the thing has protection diodes and I don't have to change all the chips, hopefully just the regu, wait, does it even have regulators there ? Hmm.
 
"That IcePower module is tiny ( 4.3 x 3.1 inches) and lives inside a combo amp - right? "
 
Yup. The smallest 180 watt amp I ever saw. Even other class Ds in that power range. It's been a while so I don't remember the makes or models. Of course that means the switchers probably weren't good enough to just use the copper on the board as a heat sink. I seem to remember some of them using TO-220s standing up with only their tabs for heatsink.
 
That link to eBay is probably the one I found. I would really like to get one cheaper because that approches what this thing sells for. These musicians are not wealthy I have found.
Phil Allison <pallison49@gmail.com>: Jan 27 06:58PM -0800


> That link to eBay is probably the one I found.
 
 
** I posted no link for ebay.
 
The first link ( Classic Audio Parts) had them for US$99 inc delivery.
 
The second from Allied Express wanted US$3795 for the same item.
 
 
 
... Phil
jurb6006@gmail.com: Jan 27 10:00PM -0800

OK.
 
Classicaudioparts obviously has an eBay account. That was the exact username on there selling for $99. I didn't look at the shipping. It said over ten available.
 
My mistake, but remember I am doing this almost blindfolded.
 
(that's no excuse, I wasn't paying enough attention)
 
Seems to me, I should go directly to the company instead of eBay though. the company makes that 18% and I can probably avoid using Paypal. Maybe. More places are going to that and fuck all that. I do not need an account at the goddamn grocery store. They are getting ridiculous. "Do you have your Walmart card ?". Just tell me what the price is, if you charge me more than others I will not come back.
 
Fucking marketing, it is the worst thing that ever happened to mankind.
 
But I digress.
Phil Allison <pallison49@gmail.com>: Jan 27 10:53PM -0800


> Classicaudioparts obviously has an eBay account. That was the exact username on there selling for $99. I didn't look at the shipping. It said over ten available.
 
** The original Icepower board is probably fixable - burnt SMD resistors can be bridged with regular 1/4 or 1/8 watt types. The old ones may need to be removed.
 
The pre-amp PCB is likely damaged - the external speaker jack on the Eden carries audio power on BOTH tip and sleeve, since the module is BTL.
 
Look for blown tracks and op-amps shorted rail to rail.
 
 
 
.... Phil
jurb6006@gmail.com: Jan 28 12:57AM -0800

>"The pre-amp PCB is likely damaged - the external speaker jack on the Eden >carries audio power on BOTH tip and sleeve, since the module is BTL. "
 
Are you fucking kidding me ? That is a stupid design.
 
Yeah I kinda figured it was BTL looking at all the copper sunk chppers on the obttom of the board. At first I said "Where the fuck are the outputs ?" and the boss says "Oh now you're using fucking foul language". I said "Fuck yeah".
 
But anyway, this unit did not appear to have any speaker output. If marketed here the UL probably mandated that because of people's stupidity. Like when a 6 amp fuse blows and it blows a new one so they go get a 20 amp.
 
Yeah, this tip and sleeve shit, you can make it adapt real nice for input huh. but for output we got a problem. The wrong plug shorts out the jack right ? then what ? Blow a fuse ? the one thing I have noticed about music equipment is that ost of it has not protection, or not enough.
 
Tell you what though, there is an exception. I got this Yammerhammer wedge powered mixer, like 600 a channel with a blown channel. That thing has protect. It is cosmetically poor, but function is worth something. Be nice not to worry if the knobs match. (is there like a color code for those ?)
 
Anyway, I got the transistors fro that, the full set, but that company diudn't have the reistors I want. Emitter resistors and a set of base resistors. They got like 47s going to the bases and double 0.47s off each emitter, three pairs.
 
The parts are wasy, but right now we are waiting until we got a decent sizable order. We own this shit so there is no rush.
jurb6006@gmail.com: Jan 28 01:06AM -0800

>"Look for blown tracks and op-amps shorted rail to rail. "
 
There is very little from board to board and I think that there is only one supply to the preamp. Only two wires and the rest are all accounted for. Line in, input, speaker out, I am tellinya, that preamp runs on a single ended source. Two wires.
 
Actually that doesn't mean shit about what you said. Rail to rail, if one rail is ground there you go.
 
I think it a good sign that the fusible is blown.
 
bottom line, do you agree that someting happened to that thing ? I mean you said this can happen when some idiot sticks a 300 watt output into a line input, OK, and I know hat lightning can do. (details some other time) But do we concur that this thing did NOT fail of its own accord ?
 
That reparadigms everything. (yes, I am now licensed to invent words)
chuck <chuck@deja.net>: Jan 28 10:18AM -0600


>Maybe we should stock up on tubes and try to gravitate towards that.
 
>Whatever. Opinions welcome. Anyone knows where to get a deal on those amp modules I would appreciate it. If you tell me a hundred bucks is a good price, I'll have to consider that.
 
>TIA
 
 
I used to work for Eden when there were two employees. I heard that
David Nordschow sold out to a Chicago company called U.S. Music. They
might have a parts department. Chuck
bleachbot <bleachbot@httrack.com>: Jan 28 03:27AM +0100

jurb6006@gmail.com: Jan 27 04:13PM -0800

>"FFS - stop being such a PITA scatterbrain."
 
Easier said than done.
 
 
I think one's a Peavey nd the other is a Crate, but I will check and get the model numbers.
 
These both mount perpendicular, in other words the board is parallel with the panel. I haven't ruin into any bad ones of other types, whether chassis or board munt, just these. Wonderr why.
jurb6006@gmail.com: Jan 27 04:22PM -0800

>their search engine kind of sucks, so it might help to go to Amphenol,
>Switchcraft, or Neutrik's page to get a part number, and then search
>for that at Markertek. "
 
I will give that a shot. Actually I am lucky to be able to get on the net at all there, I just ran AVG on two of their PCs and it was quite busy. Then I tried to install Dropbox and got it to go on one PC but not the next. Argh. Guess what kind of job I am glad not to have. So basically that's why a few things got backburnered.
 
They tell me those powered mixers sell pretty well.
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