lowell 9/9/2016 11:09 AM
Rumble 100 SMPS
Fender won't cough up the schematic for this newer model with an SMPS. Can someone send it to me? Amp came in supposedly smoking. Had some hum for me but worked. One of the main filters was bulging so i replaced it. It sparked upon powering up and now pulls too much current and blows my circuit breaker. (doesn't blow the pcb SMD fuse though). Thanks!

Also, the NTC thermistor is dead short in circuit with no power on. As I understand it, this should be a large resistance when the amp is off to suppress inrush current. If this was shorted could it cause the amp to draw too much current and REMAIN in an over current status?
 
Jazz P Bass 9/9/2016 12:11 PM
Fender will not release it.

All you get is the voltage pinout of the SMPS block diagram.
 
lowell 9/9/2016 2:44 PM
Gotcha. Thoughts on the NTC thermistor? Should it not be a short when cold? I don't believe there's anything in parallel to it. So they won't even release it to their authorized techs?
 
lowell 9/9/2016 3:32 PM
Ok so the switching MOSFET is dead short on all 3 pins. It's an 08N80C3. Other than drain current and D/S breakdown voltage, what specs do I need to meet if I were to sub. I don't have any of these in stock but do have a handful of MOSFETS in TO-220.

edit: nevermind, I don't even have any TO-220 N-channel enhancement types with a 80A rating. Will have to order.
 
J M Fahey 9/9/2016 4:04 PM
Junk it.
Thatīs what it was designed for.
Fender will not release the power amp or supply schematic for the very good reason that they have no clue themselves about it.

I donīt have Rumble 100 but 150 is a Fender designed **preamp** , tacked to a prebuilt, OEM Class D power amp and SMPS built by Ice Power , designed in Denmark but built by Terminator (not even human slaves)in automated Factories in China.

They canīt give you the schematic for the same reason they canīt give you the internal one inside, say, a TDA7294, itīs a part that you just replace when bad.

Enjoy the Terminator World:
[IMG]http://65.media.tumblr.com/c25b4873f77a38624c09184ca2915203/tumblr_nxprqi9Ktc1tg6fxfo1_1280.jpg[/IMG]

Fender Rumble 150:
http://support.fender.com/schematics...atic_Rev-B.pdf

Ice Power module (might be the same, guess itīs the smallest they have):
http://www.icepower.bang-olufsen.com...ower50asx2.pdf
2x 50W or 1 x 170W

A full power amp and supply:
[IMG]https://s-media-cache-ak0.pinimg.com/736x/fd/c8/46/fdc846924514f9a618e7861bd0f4b4c2.jpg[/IMG]

get used to it because all Fender Rumble, G&K, TC Electronics and eventually everybody else is starting to use these (or something very similar).

EDIT:they are available on EBay for U$99 , so seller pays them about U$70 and Fender must be paying around $50 each, by the container load.
How much does Fender charge a Service shop?
 
lowell 9/9/2016 4:16 PM
I think might be another one of those trends...

Transistors replacing tubes
Reverb in the 80s
SMPS now

Maybe eventually consumers will be educated on the matter and RUN from these bottom line products. I'm not saying they don't have a place in the market...but for anyone needing to depend on their gear professionally they have yet to prove themselves as reliable or "affordable" to repair.

All this said...the MOSFET is definitely shorted...I already replaced a bad filter cap...so can't hurt to toss a new MOSFET in and see what it does. I understand it's probable that more components than just the MOSFET may be bad.
 
Jazz P Bass 9/9/2016 4:37 PM
The inrush thermistor, if not measuring a lowish resistance, is probably bad.

I had one of these B&O modules on a Genz Benz bass amp that was bad.

One of the very few repairs that I refused.
 
g1 9/9/2016 6:18 PM
Like JM said, in the Rumble 150, the power amp and SMPS are a combined module and replaced as such.
Does the Rumble 100 have a separate power amp, or is it part of the SMPS module?
 
J M Fahey 9/9/2016 6:45 PM
Well, I donīt know the market value of that amplifier.
IF the owner can pay, say, $200, meaning $100 for the module and $100 to cover handling, 1 hour bench time and a little on the part itself, it still can be done.

Should have said $250 or 300 but I doubt the owner will go for it, but hey!! ,asking is free.

EDIT: a guy in Lowell (ring a bell ?) was selling these modules for U$81 ......

Bang Olufsen Icepower 50ASX2 BTL 1X170W Class D Amplifier | eBay

That said, it wouldnīt hurt trying a good MosFet there , you might get lucky.
 
lowell 9/10/2016 1:15 PM
Here's a pic
 
nickb 9/10/2016 2:16 PM
Quote Originally Posted by lowell View Post
Fender won't cough up the schematic for this newer model with an SMPS. Can someone send it to me? Amp came in supposedly smoking. Had some hum for me but worked. One of the main filters was bulging so i replaced it. It sparked upon powering up and now pulls too much current and blows my circuit breaker. (doesn't blow the pcb SMD fuse though). Thanks!

Also, the NTC thermistor is dead short in circuit with no power on. As I understand it, this should be a large resistance when the amp is off to suppress inrush current. If this was shorted could it cause the amp to draw too much current and REMAIN in an over current status?
I think having the cap on flying leads like that is a bad idea. It adds inductance in series with the transformer which in turn will lead to unclamped spikes that will take out the MOSFET. Put the correct cap on the board. Replace the NTC and the MOSFET.

Worst case this looks like a fairly simple flyback converter with a singe-chip integrated amplifier. You should be able to trace it out.

If the transformer is bad, you're out of luck (I nearly said something else).

I would not be surprised to learn that Fender don't know much about this board. They probably drew up a paper spec and some Far East company did all the engineering and put the Fender name on the silk screen. I've met some of these people - they're not stupid. Sad times for Western engineering.
 
Jazz P Bass 9/10/2016 5:22 PM
What is under the heatsink clamp?

It looks like two TDAXXXX ic's.
 
J M Fahey 9/10/2016 7:24 PM
LOWELLLLLLL !!!!!!!!
You should have posted this earlier
You send us in wild chases trying to figure out whatīs inside

Ok, I wasted time imagining it was a downgraded Rumble 150 , which does use a 100/150W ICE module, then when I read about the presumed 2 x TDA729x I thought : itīs an upgraded Rumble 75 but with an SMPS instead of a conventional supply:
[ATTACH=CONFIG]40588[/ATTACH]

clearly designed by a non-MI Engineer : absolute waste of resources: 2 x TDA7294 (capable of up to 100W RMS each) needlessly bridged, fed from less efficient +/-25V , while a single one fed +/-30/35V would have accomplished the same.

Of course, that might be fully explained by

I would not be surprised to learn that Fender don't know much about this board. They probably drew up a paper spec and some Far East company did all the engineering and put the Fender name on the silk screen. I've met some of these people - they're not stupid. Sad times for Western engineering.
I also met these people.

You go to some big Expo (think NAAMM or Frankfurt or ExpoMúsica in Brazil) and in the main floor or central area you have the HUGE Fender/Marshall/Yamaha/you-name-it stands but if you walk around, in the far corners youīll find small unadorned booths sporting a few unscrutable Chinese, dressed in Engineer uniforms (formal pants, short sleeve white shirts, pens in the shirt pocket, a fancy calculator hanging from the belt) who speak broken English ... and who represent OEM factories, large and small, which can churn out whatever you want for peanuts.
Your design ... or theirs.

More and more often I see MI amp schematics, many late Marshalls for example, and think: this was NOT designed by an MI guy, no way.

Back to lowellīs problem:
that is definitely NOT an ICE amp and supply, in fact I think in horror about the unshielded SMPS radiating trash all over the place.

Might have 2 x TDA7294 under that clamp (looooweeeellllll !!!!!!!! , please look and teeeeellllllll!!!!!! ) but that huge toroid (pair?) between chipamp and speaker out pads stinks of some Class D thingie.

And those toroid doughnuts, a heavy component *glued* on edge on a PCB, just waiting for slight rough handling (amp falling on its front/back or carelessly dumped on stage or pickup truck bed or some road bumps) to fly fee and tear wires and pads ...

Puzzled look on Chinese/Indian/Malaysian/Indonesian Engineer face: "but who would subject his computer to such abuse? ........"
 
lowell 9/19/2016 10:44 AM
Welp... the thing still ain't powering on after replacing the mosfet. Also replaced that filter with a radial lead snap in. I do see this startup resistor is toast. Now, a fried startup resistor points to a fried PWM IC. Correct? Or not? I can't read the value because it is obscured. The 2nd two of 3 digits are 02. So it reads ?02. It's R324 towards the right.

Here's a pic. Please give me some feedback...I may or may not go any further with it. Will also report back on the output IC.[ATTACH=CONFIG]40716[/ATTACH]
 
nickb 9/19/2016 11:16 AM
Your best bet now is to look up the datasheet & app notes if ness for the pwm chip. There is usually a reference design and equally often that is what you will find on the board. You will probably need to to trace out at least enough to see how it compares. Once you know the circuit you can figure out the resistance.
 
lowell 9/19/2016 11:20 AM
Thanks Nick. I did. There is not start up resistor in the datasheet. It's tied to the B+. I'm thinking I'll throw a 100ohm in there and see what happens.

https://www.onsemi.com/pub/Collateral/NCP1271-D.PDF
 
nickb 9/19/2016 11:24 AM
Quote Originally Posted by lowell View Post
Thanks Nick. I did. There is not start up resistor in the datasheet. It's tied to the B+. I'm thinking I'll throw a 100ohm in there and see what happens.

https://www.onsemi.com/pub/Collateral/NCP1271-D.PDF

Don't do that. You need to figure out what it does. For starters it's in the range 1k-9.99k. since it ends with a two.
 
lowell 9/19/2016 11:27 AM
Ah ok so SMD is like small capacitor values...IE 102 for 1nf.
 
lowell 9/19/2016 8:17 PM
Ok so tried 1k 1/2w. It fried. Have a 10k 2w in there now and its smoking. Measured v drop real quick and its 310v.

Did some calculations and even with a 10k in there the wattage is way too high. So it seems to me the PWM is pulling too much current on its HV pin...pin8.

Thoughts? I am willing to order and replace for the experience of troubleshooting SMPS. However, I don't get ANY reading from pin8 of PWM to "hot" ground. Not even on 2M range.
 
nickb 9/20/2016 1:08 AM
The maximum current thru that pin should only be 6mA (from the datasheet). Sounds like the chip and maybe more is fried. You want to use a fusible/flameproof thin film resistor in that location. It's purpose is to prevent the chip from exploding and possibly causing a fire, I would guess.
 
J M Fahey 9/20/2016 4:56 AM
Quote Originally Posted by lowell View Post
Ok so the switching MOSFET is dead short on all 3 pins. It's an 08N80C3. Other than drain current and D/S breakdown voltage, what specs do I need to meet if I were to sub. I don't have any of these in stock but do have a handful of MOSFETS in TO-220.

edit: nevermind, I don't even have any TO-220 N-channel enhancement types with a 80A rating Will have to order.
Itīs *eight* Ampere.

Dug in a litle and am surprised at the puny cheesy supply.

NCP1271 is a laptop brick class SMPS driver/controller, meant for relatively inefficient and low powered single sided driven flyback type supplies.
Datasheet example is a 19V 3A supply, go figure, so we are talking 60W DC output.
A 100W amplifier needs at least 150/200W DC power available.
I didnīt recognize in your pictures the switching MOS, where is it (they)?
Didnīt see its heatsink either.

I expect to see *at least* something equivalent to what an old 200W PC supply uses.

To boot, PCsupply hot parts are straight in the wash of an PC fan ... donīt see that here.
Bewildering.
 
lowell 9/20/2016 9:56 AM
Makes sense that when the MOSFET shorted it took the PWM with it. I'll try replacing the chip...but after that I think I'll call it on this. First gonna remove the chip and make sure something else isn't pulling current through the startup.

The data sheet says maximum current there is 100ma. Where do you see 6ma? Thanks!
 
nickb 9/20/2016 2:49 PM
Quote Originally Posted by lowell View Post
Makes sense that when the MOSFET shorted it took the PWM with it. I'll try replacing the chip...but after that I think I'll call it on this. First gonna remove the chip and make sure something else isn't pulling current through the startup.

The data sheet says maximum current there is 100ma. Where do you see 6ma? Thanks!
You are looking at the maximum "blows up if more than" ratings, not the operating conditions. Look under "Startup Current Source".

100mA is the max current you can pump in there under fault conditions w/o destroying it. To me that would suggest a series resistance of at least 3.7K to ensure that is never exceeded.
.
Say you choose a 6.8K, at 6mA it will dissipate 0.25W. So you pick a 0.5W one to act as a fuse. At 6mA it will drop 41V. I don't see a spec for the minimum HV voltage but the current is specified at HV=50V so we can that as the min. IOW, a 40V drop of your supply of (probably) 320V is fine.
 
nickb 9/20/2016 3:07 PM
Quote Originally Posted by J M Fahey View Post
Itīs *eight* Ampere.

Dug in a litle and am surprised at the puny cheesy supply.

NCP1271 is a laptop brick class SMPS driver/controller, meant for relatively inefficient and low powered single sided driven flyback type supplies.
Datasheet example is a 19V 3A supply, go figure, so we are talking 60W DC output.
A 100W amplifier needs at least 150/200W DC power available.
I didnīt recognize in your pictures the switching MOS, where is it (they)?
Didnīt see its heatsink either.

I expect to see *at least* something equivalent to what an old 200W PC supply uses.

To boot, PCsupply hot parts are straight in the wash of an PC fan ... donīt see that here.
Bewildering.
I've seen this over and over again Juan. Things are just not designed for continuous full power operation ( unless they are made by you ). The justification that is it's music so the average power is quite low.
 
lowell 9/20/2016 11:08 PM
Juan there are 4 SMD schottky diode rectifiers, clamped under the 2/8" sliver of metal to the left of the toroidal thing that is towards the middle of the board. See the metal piece just to right of it? They're under there, if that's what you're referring to as MOS. Under them is an aluminum block that's thermocoupled to the chassis.
 
Enzo 9/21/2016 4:50 PM
MOS as in MOSFET, the main switching transistors on the primary side.
 
lowell 9/21/2016 5:02 PM
Oh ...I had the one MOSFET removed cause it was shorted.
 
lowell 9/21/2016 5:06 PM
Side note - any suggestions on a largish sheet of thermal silicone? Just to have a round for cutting pieces for different projects. I searched mouser but couldn't find a whole lot of options. And the ones I found were $$. Looking for the best price.
 
J M Fahey 9/22/2016 2:54 AM
This is a Newark ad.
SIL-PAD K6 300MMX300MM SHEET - BERGQUIST - SIL-PAD K-6, .006", 12"X12" SHEET | Newark element14
Not expensive at all, U$44 for a 12" by 12" raw sheet, you can make 180 LM3886 Silpads out of it so 25 cents each.
 
lowell 9/30/2016 10:30 PM
Ok so the power amp chip is a TDA8950J. Replaced the PWM ...no help. Still in shutdown.
 
J M Fahey 10/1/2016 12:40 AM
Surprise !!!
I am actually studying SMPS, will start using them.
Iīm losing lots of sales to "brick" sized Ampeg PF350/500 , Markbass and TC Electronics miniature 300/500/700W SMPS fed Class D heads so Iīll have to design my own.

Iīm halfway through a *very* practical, hands-on repair manual, which now will try to post here.
Zero math, some shotgunning involved, minimal instruments, but, hey!!! , probably what "Joe PC supply repair Shop" uses on an everyday basis.

Only major point I diasagree with it is that they are somewhat kamikaze: ground scope to hot mains ground, consider an isolation transformer optional, trust home GFCI to cut power quickly before they die, claim grabbing a 310V charged main cap with both hands "may make you drop the TV or monitor you are repiring , picture tube will explode and sharp glass can cut you" but "shock is too short to kill you"

In that aspect itīs a suicide manual, BUT you know better, WILL use an isolating transformer and be careful with dangerous HV.

Download and read it, in your case they suggest first to measure a lot of parts, they give you a check list, replace if suspect, **separate secondary side from mains/primary side** and in your particular case: there is a starter medium power resistor (think around 2 W) which feeds the PWM controller IC straight from +300V for a few seconds until an auxiliary winding feeds it in a more efficient way.

Since it has to supply said 6 mA , or whatever starting current is needed, typical value will be around 300/0.006=50K , in fact I often see (in the book, didnīt tackle any real SMPS yet) values such as 2 x 150k resistors in parallel which means we are in the ballpark.

Obviously the 1k to 10k values you have tried so far will both burn any IC and explode themselves .... not by chance what happened so far.

Look for IC datasheet examples.

OK, Iīm trying to attach the SMPS book now:

FAIL

Book size is a 15MB PDF, way too large to upload here.
Zipped it: same thing.
Split ZIP in 5 segments, named xxx.zip , xx.z01, .... xxx.z04 and Forum software does not recognize z** as valid extensions ... oh well.

If somebody can suggest some Cloud type place accessible by anybody, Iīll upload it there.

Please not Google Cloud or any one which requires you to open an account, register, give them your blood type or free access to your home banking or similar unwarranted privacy invasions.
 
lowell 10/1/2016 1:13 AM
Juan! You rock! Thanks! I've been wanting to design some as well...but am unqualified as of yet. Can you suggest any books or resources for learning to design SMPS?

Can't wait to read this manual.
 
lowell 10/1/2016 1:20 AM
Ah...it says bad zip file. Hmmmm.... not sure where to upload it other than dropbox

Try this https://www.fileconvoy.com/
 
J M Fahey 10/1/2016 5:34 AM
Seems to work.
It will be there for 28 days only and self erase, so I suggest all those interested, even if thinking of future use, to download it now:
---------------------------------------------------
Your file(s) have been successfully uploaded.

The file(s) you have just uploaded can be retrieved using the link or URL provided below. Save this link NOW as you will not be able to get it back once you leave this page. You must send this link to every recipient of your file(s). They will be able to retrieve the file(s) by pasting this link (bold part only) into the address bar of any browser [Chrome, Firefox, Internet Explorer, Safari, Opera, etc.].

The link or URL you must send to the recipient(s) of your file(s) is:

http://www.fileconvoy.com/dfl.php?id...32d4a113dbd59f

The file(s) that can be retrieved with the above link is (are):

Practical SMPS Repair.zip (14.935 MB)

The file(s) will be available on the server for the next 28 days.
------------------------------------------------

EDIT: if you are using an ad blocker , momentarily disable it when inside fileconvoy, itīs the way they generate some revenue.
 
nickb 10/1/2016 7:06 AM
 
lowell 10/1/2016 9:26 AM
Got it. Wink wink
 
J M Fahey 10/1/2016 5:53 PM
Now itīs reading time

I suggest you go end to end once, so as to have a general idea, and then read it back , chapter by chapter, at a slower pace.
A lot of the "advanced measurement techniques" they describe are old news for us, of course
 
oc disorder 10/6/2016 1:59 PM
Sorry I'm a bit late to the party but I bring gifts ! (always a redeeming quality !!!)

Yesterday I opened a Fender Mustang... hadn't seen one before ... LCD display top panel and usual software interface ,
it's very dusty and I presume is why it resets itself on occasion especially when you don't want it!

One thing led to another and here :- (Two examples of NCP1271 in Fender circuits.)

[ATTACH=CONFIG]40928[/ATTACH][ATTACH=CONFIG]40929[/ATTACH][ATTACH]40930[/ATTACH]


I've edited these a little.. not your usual Fender schem's 'n fonts !

more here (pause b/t d/loads)

Code:
http://fender-mustang-amps-and-fuse.wikia.com/wiki/Fender_Mustang_Schematics
 
dmeek 10/7/2016 5:06 PM
Here is the schematic for the Rumble 100 SMPS


http://music-electronics-forum.com/a...1&d=1475881557
 
Jazz P Bass 10/7/2016 5:20 PM
Woo Hoo!

Thankyou dmeek.
 
lowell 10/7/2016 6:03 PM
Awesome! Thanks!
 
lowell 10/13/2016 7:04 AM
oc disorder and dmeek! THANKS! Fixed it. Boy a schematic sure helps with SMPS.

After removing and testing a bunch of secondary side components, I got frustrated cause everything seemed fine. I then studied the 1271 datasheet more, as I should have, cause it clued me in on a couple things. One, that the feedback pin was high - 3.7v. So the amp was in shutdown. After messing around secondary side, for some reason, maybe I forget what exactly I did, the feedback pin went low - .4v. So I then began to retrace my initial repairs on this, which was mainly based around the MOSFET. Testing all components in-line with the MOSFET I found R351 CS resistor from the MOSFET source to the PWM CS pin, was reading ~18k. Replaced it with closest value I had - 4.7k.

Still low secondary voltages, but now I got some pulsing happening. It's a start. So continuing my testing I found that the current sense resistor R352 was reading 20k, not the required .22ohms! Replaced it, now I got the thing working, only to find a secondary cap sizzling and smoking. I figured I had removed that cap so maybe I damaged it. Replaced it, powered up - - - - FIXED.

Thing is working and have had music playing through it for a half hour.
 
oc disorder 10/13/2016 4:58 PM
Juan
but built by Terminator
Terminator 0 Human 1
 
lowell 5/29/2017 2:50 PM
I have another one here. It's the Rumble 200. I can't even find the dang PA! Anyone? The first pic is the underside of the SMPS.
 
lowell 5/29/2017 3:59 PM
just found this on another forum! Although it's the 100. Very different from this 200, which I cannot for the life of me figure out where the PA is.
 
Enzo 5/29/2017 5:02 PM
It is an ICE module, I see the logo right on it. It is an SMPS and power amp in one.

See the black and white wires coming in top center from the mains? They enter by the gray thing. Now see the black and white wires by the upper left, are they not the speaker wires? The right side of the board is the primary side of the SMPS, the lower left is the secondary side, and the upper left is the powr amp.

Following the speaker wires is usually a good clue as to where the power amp is.

If I have followed other threads around here, there won;t be any service documentation on the ICE stuff.
 
oc disorder 5/29/2017 5:27 PM
Welcome to the Land Of Board swaps... (we tried) RUMBLE 200 = ICEPower 50ASX2 (think that one is Baby ice !)

Code:
http://www.fmicassets.com/Damroot/Original/10002/Rumble%20500%20V3%20Schematics-Diagrams.pdf

Not sure the above should be so available ?????

from search for Rumble 500
 
nosaj 5/29/2017 5:36 PM
Quote Originally Posted by oc disorder View Post
Welcome to the Land Of Board swaps... (we tried) RUMBLE 200 = ICEPower 50ASX2

Code:
http://www.fmicassets.com/Damroot/Original/10002/Rumble%20500%20V3%20Schematics-Diagrams.pdf

Not sure the above should be so available ?????

from search for Rumble 500
Just a question, how do you search or access that site to look for other modules?

Thanks,
nosaj
 
Jazz P Bass 5/29/2017 6:06 PM
Answer: you cannot.
 
Jazz P Bass 5/29/2017 6:08 PM
Quote Originally Posted by lowell View Post
just found this on another forum! Although it's the 100. Very different from this 200, which I cannot for the life of me figure out where the PA is.
The Rumble 200 uses the 50ASX2 module.
[ATTACH]43669[/ATTACH]

The full datasheet: [ATTACH]43670[/ATTACH]
 
oc disorder 5/29/2017 6:09 PM
Search me ! Just found it with Google..


There is some interesting reading re Ice modules here although in German.

Code:
http://www.hifi-forum.de/viewthread-71-11152-5.html
Google Translate
https://translate.google.com.au/tran...tml&edit-text=
 
lowell 5/29/2017 6:40 PM
This might the most odd thing I've in a while. Fender using such a module. Don't get me wrong I know it is done...but...to have a completely separate identity than the amp it is installed in. Weird. Odd.

So I just get one on ebay and boom. ?

Is this class D? That's my guess.

Thanks everyone.
 
Jazz P Bass 5/29/2017 6:46 PM
Man, you gotta love Google Translate.
From the sbove listed forum:
"A true symmetrical signal transmission has therefore no audio mass! "
 
nosaj 5/29/2017 6:52 PM
Quote Originally Posted by lowell View Post
This might the most odd thing I've in a while. Fender using such a module. Don't get me wrong I know it is done...but...to have a completely separate identity than the amp it is installed in. Weird. Odd.

So I just get one on ebay and boom. ?

Is this class D? That's my guess.

Thanks everyone.
Bang & Olufsen ICEpower 50ASX2 SE 2x50W Class D Amplifier UNUSED
nosaj
ICE Power 50ASX2 Power Amplifier Bang & Olufsen 50 ASX2 | eBay
 
Jazz P Bass 5/29/2017 7:15 PM
Quote Originally Posted by lowell View Post
This might the most odd thing I've in a while. Fender using such a module. Don't get me wrong I know it is done...but...to have a completely separate identity than the amp it is installed in. Weird. Odd.

So I just get one on ebay and boom. ?

Is this class D? That's my guess.

Thanks everyone.
Yes it is class D.

Make darn sure that you have a signal going into the module, as the module may not be the fault.

Fender is not alone in using the modules.
Bang & Olufsen must have one heck of a sales team.
Genz-Benz (when they existed) & Yorkville also come to mind as using the Ice module.
 
Leo_Gnardo 5/29/2017 7:26 PM
Quote Originally Posted by nosaj View Post
Bang & Olufsen ICEpower 50ASX2 SE 2x50W Class D Amplifier UNUSED
nosaj
ICE Power 50ASX2 Power Amplifier Bang & Olufsen 50 ASX2 | eBay
Kool! $100 a pop, ships from beautiful downtown Montebello CA just south of LA. Now I know not to get into a panic when I run across a bad one. 83 sold - all the seller needs to do is keep up the good work then he can rival McDongle's - "over 150 billion sold!"
 
Jazz P Bass 5/29/2017 7:41 PM
And if the repairs really come rolling in, here is a deal: ICE Power 50ASX2 5 pack.
ICE Power 50ASX2 Power Amplifier Bang & Olufsen 5 pack | eBay
That brings a single unit down to $90.
 
Enzo 5/29/2017 8:39 PM
Lowell, this doesn;t say Fender on it, but it really is no different from building an amp and using a LM3886, a TDA7293, or even a TDA2030. WHy design a whole thing when the exact thing already exists as a drop in part? Those are entire power amps in one module.
 
lowell 5/29/2017 11:23 PM
I see what you're saying.
 
SCAMP_2052 6/19/2017 8:53 AM
Picked up a "fixer" Fender Rumble 500 Combo on CL.
Tag: 'Overdrive' LED lights at high power with some clipping/volume reduction.
Finding #1: 24 VDC Aux SMPS drops as low as 16V8 during high power pulse. This is below the Vdrop for the 7X15xx regulators.
Query: I'm not sure if this the root cause, or a side effect of the systems overload protection circuits.
Query: Anyone seen this before?
Ref: http://music-electronics-forum.com/t42841-2/
 
Enzo 6/19/2017 9:24 AM
My reaction is the SMPS is cycling, trying to rid itself of excess load, most likely in the power amp. Alternately a shorted or very leaky rectifier in the secondary side of the SMPS.

Welcome to the forum. May I suggest you start a new thread for your unit, rather than tack on the end of a long existing one. That reduces confusion, and you will get better response with a new thread.
 
SCAMP_2052 6/19/2017 5:42 PM
Thanks for the tip! I've opened a new thread under "Class-D Amplifiers", http://music-electronics-forum.com/g...iscussionid=10
 
Enzo 6/19/2017 6:00 PM
We have a section just for class D amps?
 
The Dude 6/19/2017 6:09 PM
Enzo: From what I can tell he started a new "Group" instead of just a new forum thread.

Scamp: To my knowledge, posts from specific groups don't show up in the normal forum legend (New posts, Today's posts, etc.) So, few are going to see your new Group or posts within it. You'd be best just starting a normal thread in the forum for your amp- like all others.
 
SCAMP_2052 6/19/2017 7:28 PM
I killed the group 'Class-d amplifiers'. Thanks for the tip.
 
Enzo 6/20/2017 5:45 AM
Oh.

Well, nothing against it, I just never knew we had "groups". What is it, like a side chat room or something?
 
lowell 6/20/2017 9:09 AM
I received the new ICE module. After installation, I may use it as a reference to fix the original one. Depending on how much of a priority I make it.

I'll report on my findings if any.