I am repairing a Massive Nano N2 800.1 monoblock amp, seems to be just 2 IRF640N that went bad, it powers up good, no more protect, on 12v2a out of heat sink but was only drawing maybe .6a and had a pretty loud buzzing, I still need to do more testing and put my scope on it but when measuring the glass diode at D35 only measured .06v while the above at D37 measured .6v, which from some reading is nominal? Is the diode at D35 off spec, maybe connected to the circuit with the removed blown mosfets, and that being the reason why it’s off spec? Any help with these glass diodes is greatly appreciated, I’m off to read more and try to find more info, thx and take care all!
Below is close up pic of D35 & D37 and their distance from the output mosfets, I’m assuming they are somehow connected, I’m still learning class D topology 😅
Below is close up pic of D35 & D37 and their distance from the output mosfets, I’m assuming they are somehow connected, I’m still learning class D topology 😅
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In some amps, it's difficult to tell what the diodes are because there is only a single black band and no other markings. In MANY cases, these are all 1N4148 type switching diodes. In your board, the Zener diodes are designated ZDx, so that helps to distinguish Zeners from switching diodes. In some instances, a glass SMD diode will have a blue band and these are typically Zeners but the value isn't indicated.
In your amp, the diode reading 0.06v is in parallel with a 22 ohm resistor.
For my reference only:
2A[2] - ty
In your amp, the diode reading 0.06v is in parallel with a 22 ohm resistor.
For my reference only:
2A[2] - ty
Ahh ok, ya I read that as well about the markings not being the clearest for this type and some degree of difficulty identifying, also just to make sure because it was a quick reading with my cheap o meter I used my better meter to reread that zener diode @D35 and it reads it at .027v, D37 reads .656, just thought I’d correct myself since I saw the difference, don’t think I’m going to use that cheap $3 meter anymore ...
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In a situation like this, I'd apply new solder to both sides of the 22 ohm resistor, heat one end and quickly move the iron to the other end, pushing the resistor to an unpopulated area of the board. Remove any solder bridges (if there are any) and check the diode.
You know the resistor value so you don't risk anything moving the resistor as you might if you damaged or lost the diode when moving it.
You know the resistor value so you don't risk anything moving the resistor as you might if you damaged or lost the diode when moving it.
Diode tested good, no problems. ty for helping point that out, didn’t even realize the 22ohm resistor was wired in parallel reducing the reading of the diode, but when you look at the traces on the board it’s obvious, ty Perry🙂
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After checking a few things and confirming all is in working order I successfully finished my 1st repair, this Massive amp (still waiting on inductor wire for that ZX750.1) You, Bill, and Todd from Ellensburg’s have taught me so much, I really appreciate the time you put into us newbs, ty!
🦾🤖🔊
🦾🤖🔊