Hopefully this one is a little more simple. Rockford Fosgate 250a2 PC-2035-G. Typical blown channel, but when I went to replace an open source resistor I noticed they are 0.03 ohm, not 0.1 ohm as I'm used to seeing. Also, R261 & R235 are 0 ohm jumper "resistors", and R262 & R234 are excluded. The amp hasn't been worked on before, and matches another 250a2 I looked at.
The main issue is I don't see much available for 0.03/30mOhm 3W 5% resistors. If I changed to a 0.1ohm source resistor, would I restore R261 and R262 like the earlier revisions? I only have schematics for Rev B & Rev C, which show 0.1 ohm source resistors and R261 as 20 ohm, R262 as 10 ohm. The IRF540 side of the 200 channel is the only damage (inc/R252, Q216, D204). Would I do the IRF9540 side as well?
The main issue is I don't see much available for 0.03/30mOhm 3W 5% resistors. If I changed to a 0.1ohm source resistor, would I restore R261 and R262 like the earlier revisions? I only have schematics for Rev B & Rev C, which show 0.1 ohm source resistors and R261 as 20 ohm, R262 as 10 ohm. The IRF540 side of the 200 channel is the only damage (inc/R252, Q216, D204). Would I do the IRF9540 side as well?
Attachments
(R236 leg is lifted just to verify the source resistor value, which checked out at 0.03ohm as indicated).
I'd replace all FETs in the channel where there were any that failed.
Mouser and dIgikey both have 0.03 ohm resistors. Using the original value would be my choice. If you decide to modify it and you don't intend it for personal use, you're responsible for testing to determine if the protection circuit works the same in both channels (modded and OEM). I'd prefer to see the OEM values used if the owner is paying to have the amp repaired (not re-engineered).
https://octopart.com/search?categor...e=Axial&resistance=(0.03__0.03)&powerrating=2
Mouser and dIgikey both have 0.03 ohm resistors. Using the original value would be my choice. If you decide to modify it and you don't intend it for personal use, you're responsible for testing to determine if the protection circuit works the same in both channels (modded and OEM). I'd prefer to see the OEM values used if the owner is paying to have the amp repaired (not re-engineered).
https://octopart.com/search?categor...e=Axial&resistance=(0.03__0.03)&powerrating=2
2w according to the diagram. Look at the part number under the designation on the diagram. RM/10 is 1/10 watt. an RM2 is a 2 watt
I see your point, but isn't that the same designation on others like the 800, where 3W has been suggested in the past? I'm not trying to be argumentative, they just look like the same size as on the other amps and I thought yourself & Sean Michael Kane (and my own physical measurements) pointed towards 3W
I used the 3w when the LVR series were available because they were the same size as the Rockford 2w.
Wattage is determined by the heat that the resistor's components can withstand for a given power dissipation. The ability to dissipate heat is determined by the resistor's size.
Use what you think is right.
Wattage is determined by the heat that the resistor's components can withstand for a given power dissipation. The ability to dissipate heat is determined by the resistor's size.
Use what you think is right.