Hello All
I'm working on an amp for a buddy of mine, he says it blew from having his subs wired at a .3 ohm load.
I'm not thinking so. Could someone chime in and give me their thoughts on what may have caused the amp to fail?
I'm working on an amp for a buddy of mine, he says it blew from having his subs wired at a .3 ohm load.
I'm not thinking so. Could someone chime in and give me their thoughts on what may have caused the amp to fail?
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The damage you see is fact of very low load at the output. YES 0.3R make this problem. i am pretty sure that not all the Power Supply Mosfet are burned. the reason is that not all the transistors came identical from the production some of them "brake" at lower current some of them not.
anyway now you need to replace ALL the Power Supply mosfet transistor not only the burned transistors
anyway now you need to replace ALL the Power Supply mosfet transistor not only the burned transistors
OK, Thankyou. makes sense lower ohm load = higher current draw & heat.
Correct. Not all was damaged. I have and planned to replace all of them plus gate resistors.
The audio section surprisingly looks like it is untouched.
Correct. Not all was damaged. I have and planned to replace all of them plus gate resistors.
The audio section surprisingly looks like it is untouched.
There is resizing and there is a quality setting when saving. Reduce the quality but leave them full size... or email the full resolution images to me.
babin_perry@yahoo.com
babin_perry@yahoo.com
I wanted to see if the transformers were in series. They don't appear to be.
If any of the power supply FETs survived, save them for testing (don't install them in a repair that you're getting paid for.
If you remove the output with the face blown off of it, do read a short from pads 1-2, 1-3 or 2-3?
If any of the power supply FETs survived, save them for testing (don't install them in a repair that you're getting paid for.
If you remove the output with the face blown off of it, do read a short from pads 1-2, 1-3 or 2-3?
Legs 2 and 3 are shorted.
I've never messed with a dual power input amplifier before. When I touch my probes to the power terminals negative to positive and positive to negative it shows dead short. But pos to pos and neg to neg all seems fine. Is this normal because of the board design? Please forgive the rookie question.
I saved the power fets that didn't burn. I've got a complete new set of 25v 3300caps, power fets, gate resistors & rectifiers. And will be ordering a new set of outputs now also
I've never messed with a dual power input amplifier before. When I touch my probes to the power terminals negative to positive and positive to negative it shows dead short. But pos to pos and neg to neg all seems fine. Is this normal because of the board design? Please forgive the rookie question.
I saved the power fets that didn't burn. I've got a complete new set of 25v 3300caps, power fets, gate resistors & rectifiers. And will be ordering a new set of outputs now also
They are the IR21844S or IRS21844S (IRS is the newer version and generally good, no matter the original).
You need to read for at least an hour, all of the threads that deal with the 21844s. It will make the repair easier.
The power supply drivers may have failed. The BD139 and BD140 are commonly used to replace the original transistors, if the originals are not available.
Check all gate resistors for the outputs and PS FETs.
You need to read for at least an hour, all of the threads that deal with the 21844s. It will make the repair easier.
The power supply drivers may have failed. The BD139 and BD140 are commonly used to replace the original transistors, if the originals are not available.
Check all gate resistors for the outputs and PS FETs.
Ok, Thanks for your help and the info. I'll get started on the reading. And get the gates checked out in the morning.
I'm not charging for the repair. It's more for a learning experience.
I'm not charging for the repair. It's more for a learning experience.
Well....all "most" of the parts are in. time to get back on this beast.
Would anyone happen to have a schematic for a VFL audio 8k?
Would anyone happen to have a schematic for a VFL audio 8k?
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