Let me introduce my self im a newby this my first post. I have very limited tools and basically just have a multimeter and soldering iron and very basic knowledge of amps but i love fixing things and i have a love for old school usa fosgate amps. Im wondering if i could get a schematic for a 250a2 board # is 2035-H. I know i have shorted power supply fets on both amps and way out of tolerance gate res to same side on both amps. I have stupid ? Do i have to pull out all the output irf9540's and irf540's to check or can i leave them in? Thanks for any help. And ive been reading some threads and Perry your a genius. Thanks Travis. Sorry for long post
Please use one thread for each amp if you need help with them.
See attached. It's B but it's likely close.
Don't confuse knowledge with intellect.
You can check for shorted internal connections but you have to remove them for more definitive tests (as a last resort).
See attached. It's B but it's likely close.
Don't confuse knowledge with intellect.
You can check for shorted internal connections but you have to remove them for more definitive tests (as a last resort).
I hope i can fix it. output transistors are reading complete short across all legs no matter how u check it circuit. Also let me add this amp had been prev worked both mtp75n05's were raised and not soldered down to strip. When i applied power and rem it instantly popped ps fet q6. Then i checked there was a short across + and - input on amp i clipped that fet out now 98ohms across + and -.
With most Rockford amps, you can check the drive circuit for the FETs by connecting only remote and ground (no B+). If you do this with the PS FETs in the circuit, you can tell if there is damage to the drive circuit.
You likely have defective driver transistors or out of tolerance gate resistors.
If all of the outputs are reading 0 ohms across all legs, you'll need to remove them before you try to power up the amp again.
You likely have defective driver transistors or out of tolerance gate resistors.
If all of the outputs are reading 0 ohms across all legs, you'll need to remove them before you try to power up the amp again.
thank you and yes the gate res are bad on one side supposed to be 68ohms and are up in the K range. this will be a slow repair as I don't have any parts here. I have ordered ps supply fets pt# Irf 3205 and surface mount res. 47 0hm from china as seen from other threads you were helping out in. I have bare minimum tools I don't even have a power supply except car wiring. I'm gonna start looking for a power supply. I also ordered output fets also as figure there prob bad. Gotta wait for that stuff to come in I guess. Thanks for your help Perry your the best if you think of something else I can check in the mean time let me know thanks!
Why from china? Too many counterfeit parts.
If you're in the US, order from Digi-key or Mouser when ordering in small quantities.
If you're in the US, order from Digi-key or Mouser when ordering in small quantities.
No. The drivers are Q1, 2, 4 and 5. The PNP drivers commonly fail. The drivers are MMBT3904 and MMBT3906.
Thanks for info actually only res coming from china rest is ebay from usa but that might not be much better? Thanks i will look at those
I'd advise against using NTE substitutes and buying from ebay. If you need a funky fishing hat, ebay is fine. For electronic parts, not so much.
You can get 2-day USPS service from either DK or Mouser for about $7.
You can get 2-day USPS service from either DK or Mouser for about $7.
Hi Whosnxt,
It's not even worth trying the parts from China. Get them from a real distributor like Mouser or Digikey. There are other good suppliers also. Most will have parts in your hand in a day or two just to really give them a push.
What was the Ebay store / seller you got them from?
Back to Perry ...
-Chris
It's not even worth trying the parts from China. Get them from a real distributor like Mouser or Digikey. There are other good suppliers also. Most will have parts in your hand in a day or two just to really give them a push.
What was the Ebay store / seller you got them from?
Back to Perry ...
-Chris
Check what? The drivers?
They can be checked in the board but it's probably easiest to test with remote and ground connected. The emitters of the drivers should read approximately the same as pins 9 and 10 of the TL594. This is most reliable when the gate resistors and the PS FETs are in the circuit.
They can be checked in the board but it's probably easiest to test with remote and ground connected. The emitters of the drivers should read approximately the same as pins 9 and 10 of the TL594. This is most reliable when the gate resistors and the PS FETs are in the circuit.
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