Hello Q6 and Q7 originally were MTP50N06V which can be found on ebay. You can use those again but I recommend IRF3205. The gate drivers for those originally were 68 ohm (805) size. Perry mentioned those my be a bit high for the IRF3205 and to use a 47 ohm (805) size. I personally have used 68 ohm in many repairs with the IRF 3205 and have NEVER had any issues. CR1: FEN16BT 9612 CR2: 9629 U1610 These are OEM parts.
Replace CR1, CR2, Q6, Q7, R19, D3, D2, Q1, Q2, Q4, Q5, then before powering up turn bias pots fully counter clockwise. Check Q119, Q115, R150, R152, R136, R163, Q215, Q219, R250, R252, R236, R263. If those check out ok fire it up. Then set bias and test your sound. Hope this helps...
I recommend the 47 ohm resistors because they're always safe. The 68s can be marginal on some amps. There are no amps (that I know of) that use anything greater than 47 ohm resistors with 3205s unless there is some additional deadtime built into the drive circuit (i.e. Kicker).
Sometimes it's not apparent that the gate resistor value is too high in amps that use regulation (like many of the Rockford amps) because the reduction in pulse width at idle masks the problem.
In my opinion, it's well worth the time and expense to replace the gate resistors.
Sometimes it's not apparent that the gate resistor value is too high in amps that use regulation (like many of the Rockford amps) because the reduction in pulse width at idle masks the problem.
In my opinion, it's well worth the time and expense to replace the gate resistors.
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