rockford punch 500.2

[scampo77]

i am having the same problem on 2 amps i am tryiing to fix and i am hoping that if i can fix one i can figure out what is wrong with the other

i pulled the outputs and the power supply FETs and when i put in a couple power supply fets back in that i checked for shorts the outputs (irf 3205) got hot right away. my power supplies are irf9540 + 540 (i possibly have the power and outputs mixed up)

i cant see any obvious solder bridges that would be causing the short

i am tryiing to post as much info as i know how to, and i guessed at these i measured these with 2x irf9540s installed and 2x irf540s installed and no 3205s installed

tl494c

1 0
2 4.7
3 0
4 0
5 1.5
6 3.3
7 gnd
8 14.5
9 5.8
10 5.8
11 14.4
12 14.4
13 4.9
14 4.9
15 4.9
16 0


lm339d

1 5
2 5
3 14.5
4 .1
5 2.2
6 4.8
7 4.9
8 4.9
9 5.5
10 5
11 9
12 gnd

[Perry Babin]

With only remote and ground connected (no B+), what is the DC voltage on the gate solder pad for EACH of the power supply FETs?

Yes. You have them backwards. The 3205s are the power supply FETs and are near the transformer.

What are the markings on the gate resistors for the 3205s?

[scampo77]

all are 5.8v and the resistors are 680 (68 ohm)

[Perry Babin]

The 68 ohm may be a bit high for the 3205s. I'd suggest going to 47 ohm gate resistors. I know those are OK with the 3205s in Rockford amps.

[scampo77]

you think that if i just change those resistors that it will make the amp work again?

i dont know if it matters abut all the FETs were completely burnt and blown apart when i got this amp.

[Perry Babin]

The resistors may make the FETs run cooler but there may be other problems. How much current was it drawing when you power it up previously?

[scampo77]

with one 3205 in there it is drawing 2.5 amp

i have the 2ohm 40 watt resistor engaged on the power delivery tho

[Perry Babin]

You need at least one on each side.

[scampo77]

im still at about the same 2.4 amp and both sides are getting hot

[Perry Babin]

Do you read ~130 ohms between the gate pads for the power supply FETs on either side?

Do you have any 47 ohm resistors (through-hole or SMD)?