UPDATE: Repairing the T2500BDcp was a success. i replaced the Fets that were burned up, the resistors for the Fet gates, And all 6 large Caps in the middle of the PCB. Amp was powered on with PSU, then tested in vehicle. Been operating perfectly since the repair. Big thanks to Perry and Sean for the help with this repair.
Bellow are links to the parts purchased for this repair:
Caps:
https://www.mouser.ca/ProductDetail...=sGAEpiMZZMvwFf0viD3Y3RXRUVU1xXQD9CLHTwrPmBE=
Fets;
https://www.mouser.com/ProductDetai...=/ha2pyFadujrBXnjz2f3uH2UGSQ52ZfgCeohZ4vJCFI=
gate resistors:
RC0805FR-0760R4L Yageo | Mouser Canada
Theses Parts where a direct replacement and work great.
Thanks again guys!
Original Post: After hearing a "sparking" noise after turning on my amps for a while in my truck, ive decided to tear down my amp to see what the fuss was about.
I found loose caps and a burn Mosfet leg.
id like to order theses parts but the not quite sure as the part numbers on the components are hard to find online.
If someone here can help me out and point me to the right caps and mosfets on mouser or digikey that be great. Im worried to buy the wrong ones.
the Part number on the Mosfets are :75344g , on top of that theres a "F" 1A17AA
The caps mesure 36mm high seated, 36mm in diameter, 1500uF , 200V , 105C
theres so many to choose from on digikey and mouser. If someone can help, greatly appreciated !
Bellow are links to the parts purchased for this repair:
Caps:
https://www.mouser.ca/ProductDetail...=sGAEpiMZZMvwFf0viD3Y3RXRUVU1xXQD9CLHTwrPmBE=
Fets;
https://www.mouser.com/ProductDetai...=/ha2pyFadujrBXnjz2f3uH2UGSQ52ZfgCeohZ4vJCFI=
gate resistors:
RC0805FR-0760R4L Yageo | Mouser Canada
Theses Parts where a direct replacement and work great.
Thanks again guys!
Original Post: After hearing a "sparking" noise after turning on my amps for a while in my truck, ive decided to tear down my amp to see what the fuss was about.
I found loose caps and a burn Mosfet leg.
id like to order theses parts but the not quite sure as the part numbers on the components are hard to find online.
If someone here can help me out and point me to the right caps and mosfets on mouser or digikey that be great. Im worried to buy the wrong ones.
the Part number on the Mosfets are :75344g , on top of that theres a "F" 1A17AA
The caps mesure 36mm high seated, 36mm in diameter, 1500uF , 200V , 105C
theres so many to choose from on digikey and mouser. If someone can help, greatly appreciated !
Last edited:
These might be an ok choice.
https://www.mouser.com/ProductDetai...=sGAEpiMZZMvwFf0viD3Y3RXRUVU1xXQD9CLHTwrPmBE=
The power supply FET's are HUF75344G3
HUF75344G3 ON Semiconductor / Fairchild | Mouser
Check the drivers on the pwm card and the gate resistors for the power supply FET's as well.
https://www.mouser.com/ProductDetai...=sGAEpiMZZMvwFf0viD3Y3RXRUVU1xXQD9CLHTwrPmBE=
The power supply FET's are HUF75344G3
HUF75344G3 ON Semiconductor / Fairchild | Mouser
Check the drivers on the pwm card and the gate resistors for the power supply FET's as well.
Measure the height and diameter of the original caps.
The caps are in 2 sets of 3. Do you have at least one in each group of 3 that is still OK (no broken legs or solder connections)?
You stated that the amp was making noise. Was it still playing?
seankane:
Are the 200v caps common? I've never seen anything more than 160v in any Rockford amp.
Do you have a scope?
What are you using for a 12v power supply?
Do you have a multimeter?
The caps are in 2 sets of 3. Do you have at least one in each group of 3 that is still OK (no broken legs or solder connections)?
You stated that the amp was making noise. Was it still playing?
seankane:
Are the 200v caps common? I've never seen anything more than 160v in any Rockford amp.
Do you have a scope?
What are you using for a 12v power supply?
Do you have a multimeter?
Hi perry
Only one cap went bad the others are fine. I was thinking of replacing all the caps, if it’s unnecessary then ill just replace the caps in the one bank.
Also only 1 mosfet burnt up. What causes mosfets to burn up?
The amp turned on (once in a while arcing noise), once it was on, it played fine without issues. No noises. Wouldnt of been able to tell something was wrong with it.
As for the caps, it says 200v, 1500uf, 105c. 36mm height seated, 35mm roughly in diameter.
I do have a fluke scope. But no idea on how to diagnose an amplifier as its my first one. I do have a soldering iron for electronics and fluke multi meters.
Ive done other past electronics repairs in other aspects, but not amplifiers.
Thanks!!
The gate resistors, would they be in the same circuit as the the mosfets?
I also wouldnt know where the location is for the drivers on the pwm board
Only one cap went bad the others are fine. I was thinking of replacing all the caps, if it’s unnecessary then ill just replace the caps in the one bank.
Also only 1 mosfet burnt up. What causes mosfets to burn up?
The amp turned on (once in a while arcing noise), once it was on, it played fine without issues. No noises. Wouldnt of been able to tell something was wrong with it.
As for the caps, it says 200v, 1500uf, 105c. 36mm height seated, 35mm roughly in diameter.
I do have a fluke scope. But no idea on how to diagnose an amplifier as its my first one. I do have a soldering iron for electronics and fluke multi meters.
Ive done other past electronics repairs in other aspects, but not amplifiers.
Thanks!!
The gate resistors, would they be in the same circuit as the the mosfets?
I also wouldnt know where the location is for the drivers on the pwm board
It appears that the amp has only minor issues.
At the very least, I'd remove the other caps and see if the leads look stressed. If any rattle when you shake them I'd replace them.
If one of your fluke meters measures capacitance, check them when they are out of the board.
The drivers likely survived if the amp still works normally but if you have a scope, compare the drive signal on the gates of all of the PS FETs (don't let the probes slip).
Check the value of the PS FET gate resistors, especially the one for the failed FETs.
When you get the capacitors installed, apply a bit of adhesive to the tops of the caps where they nearly touch. I use E6000 or Goop but anything that will bridge the gap and remain in place is better than nothing.
At the very least, I'd remove the other caps and see if the leads look stressed. If any rattle when you shake them I'd replace them.
If one of your fluke meters measures capacitance, check them when they are out of the board.
The drivers likely survived if the amp still works normally but if you have a scope, compare the drive signal on the gates of all of the PS FETs (don't let the probes slip).
Check the value of the PS FET gate resistors, especially the one for the failed FETs.
When you get the capacitors installed, apply a bit of adhesive to the tops of the caps where they nearly touch. I use E6000 or Goop but anything that will bridge the gap and remain in place is better than nothing.
The gate resistors are directly connected to the gate leg of the FETs. It's R1011 for the FET that burned.
Good call. That resistor is shot for that fet. All the other resistors measure a solid 60.4ohm. Would you know the part number for that gate resistor? The numbers are too small for me to read them
It's a 60.4 ohm in 0805 size (confirm with dial caliper), 1% tolerance.
Did you check all 12 resistors for all 12 PS FETs.
Did you check all 12 resistors for all 12 PS FETs.
Perry I have never seen 200V caps in a 2500 only 160v as you stated.
Maybe somebody else has changed them, or if this is a brand new amp maybe an upgrade in production?
Maybe somebody else has changed them, or if this is a brand new amp maybe an upgrade in production?
The first 3 resistors are blue in color and have 47.4ohms (undamaged) - r1007, r1009, r1008
The others all have 60.4ohms. (One burnt up)
What causes a fet to fail? Do they have a switching limit? Should i be replacing all 12 while i am in there?
You can have random failures. I'm assuming that the amp is not being driven into a load below what the manufacturer recommends.
Are you familiar with amp repair, in particular cleaning the old heatsink compound and replacing it?
Don't try powering the amp up without having the semiconductors clamped to the heatsink.
Are you familiar with amp repair, in particular cleaning the old heatsink compound and replacing it?
Don't try powering the amp up without having the semiconductors clamped to the heatsink.
The amp is at 1.3 ohm load I believe, i dont drive it hard either (as i am getting older)
Yeah i am an electric vehicle engineer for mining equipment. I do have the electrical high voltage back round and fixing pcb boards. We have datasheets for our stuff tho that makes repairs breezy. This amp, i dont even have a schematic lol.
Ive cleaned the frame and have new compound for it. I wanted to be certain on the parts i am replacing and understand why they have failed.
Would you replace all mosfets or just the one burnt up?
Would you happen to have a data sheet part number for that 60.4 ohm resistor, there is quite a few of different ones on mouser. Can you send me a url link to the one you see fit as a replacement? Im sure it will help others as well for future repairs 🙂
Yeah i am an electric vehicle engineer for mining equipment. I do have the electrical high voltage back round and fixing pcb boards. We have datasheets for our stuff tho that makes repairs breezy. This amp, i dont even have a schematic lol.
Ive cleaned the frame and have new compound for it. I wanted to be certain on the parts i am replacing and understand why they have failed.
Would you replace all mosfets or just the one burnt up?
Would you happen to have a data sheet part number for that 60.4 ohm resistor, there is quite a few of different ones on mouser. Can you send me a url link to the one you see fit as a replacement? Im sure it will help others as well for future repairs 🙂
60.4 ohm resistor 1% 0805 | Octopart
Confirm that they're 0805.
You need to replace the two other FETs that are in parallel with the one that failed. I'd replace the gate resistors for these 3 FETs as well.
The attached diagram is from an older model but the power supply and some of the output stage are similar.
Remember to check the drive at the gate of the PS FETs before you consider this repaired.
Confirm that they're 0805.
You need to replace the two other FETs that are in parallel with the one that failed. I'd replace the gate resistors for these 3 FETs as well.
The attached diagram is from an older model but the power supply and some of the output stage are similar.
Remember to check the drive at the gate of the PS FETs before you consider this repaired.
In post 14, I forgot to mention that the 3 new FETs need to be from the same production batch (have same date code) so that they're relatively closely matched. Buying in small quantities means that the parts may be picked from a bin and may not have all of the same date codes. I'd order extras to improve the chances of getting 3 matching.
Perry, this is very interesting, 3 fets from the same batch...., is that a preference ? or an absolutely NEED. Ive never heard of this before. I should be making the order today.
I really appreciate all the help guys. Would have never thought, some thoughtful people like you still willing to help a guy get his amp back up and running. Very appreciated just so you know. I will update the first post of this thread once the amp repair is complete and working
I really appreciate all the help guys. Would have never thought, some thoughtful people like you still willing to help a guy get his amp back up and running. Very appreciated just so you know. I will update the first post of this thread once the amp repair is complete and working
If you've dealt with checking semiconductors, I'm sure that you've seen that they don't always read precisely what the datasheet lists. For example, if you're checking the Hfe/beta for a group of transistors, they will vary greatly. They will even vary if the heat of your fingers changes their temperature.
Parts from the same batch will also have such variations but being from the same batch, from the same die layout, the same materials... will make them more likely to have their properties change in the same way.
Some people go farther and do further tests to get them even closer. I will sometimes do that but parts from the same batch are generally good enough.
I started doing this just a few years into doing repair work when I saw one of the parts I replaced (as part of a parallel group) fail, when the other parts survived. It was often one that didn't match.
Parts from the same batch will also have such variations but being from the same batch, from the same die layout, the same materials... will make them more likely to have their properties change in the same way.
Some people go farther and do further tests to get them even closer. I will sometimes do that but parts from the same batch are generally good enough.
I started doing this just a few years into doing repair work when I saw one of the parts I replaced (as part of a parallel group) fail, when the other parts survived. It was often one that didn't match.
How would i go about checking the drive at the gate of the PS ?
Also for your previous statement in regards to trying to get from the same "batch" If i am replacing only 3 fets, the other 9 in the amplifier will remain original. This would mean 3 new ones would be from a different batch of the other 9. Does this matter? should i replace all 12 FETS then?
The ones in parallel are the ones that need to match. There are only 3 in parallel.
What model scope do you have?
What model scope do you have?