I have a RF Series 1 260sd amplifier that after sitting dormant for years now has very reduced output in the right channel. By reduced, I mean it is only putting out 1/4 of what the left channel is capable of. Not only that, there is what I feel to be way too much cross talk when only one channel (either one) is driven. Outside of this, the amp does not get hot when running.
One of the daughter boards (vertical boards), located just behind the amp inputs, looks to be a gain stage and/or speaker level to line level conversion board containing a bunch of SMT resistors, capacitors and an LM833 chip. The output pins of the LM833 chip look to show the same difference in AC output between the two channels, so the issue may be between the RCA input jacks and the chip. If it means anything, the LM833 has a 30V DC potential between its power pins (4,8).
So here are my questions:
1. Can I remove the main board from the heat sink and still power it up to test without burning anything up? Do the output and PS fets need the heat sink to run at idle and/or into say a 40 ohm test load at very reduced output?
2. Has anyone run into this kind of situation and have an idea as to where the issue(s) may lie?
3. Although I have the main board schematic, I do not have the schematic for the daughter boards. I have contacted Rockford and requested them, but they stated they didn't have them readily available and will have to work with engineering to find them before sending. Does anyone already have these schematic for the boards labeled as such below:
1. Input Board: M1, WP-PCS1IC
2. Gain Boards? (there are 2 of them, but both are the same): M3 & M4: S1DD, WP-PCS1DRC
3. Power Supply Board: M2, S1PP, WP-PCSIPC
ANY help on this would be greatly appreciated.
Thank you,
Steve
One of the daughter boards (vertical boards), located just behind the amp inputs, looks to be a gain stage and/or speaker level to line level conversion board containing a bunch of SMT resistors, capacitors and an LM833 chip. The output pins of the LM833 chip look to show the same difference in AC output between the two channels, so the issue may be between the RCA input jacks and the chip. If it means anything, the LM833 has a 30V DC potential between its power pins (4,8).
So here are my questions:
1. Can I remove the main board from the heat sink and still power it up to test without burning anything up? Do the output and PS fets need the heat sink to run at idle and/or into say a 40 ohm test load at very reduced output?
2. Has anyone run into this kind of situation and have an idea as to where the issue(s) may lie?
3. Although I have the main board schematic, I do not have the schematic for the daughter boards. I have contacted Rockford and requested them, but they stated they didn't have them readily available and will have to work with engineering to find them before sending. Does anyone already have these schematic for the boards labeled as such below:
1. Input Board: M1, WP-PCS1IC
2. Gain Boards? (there are 2 of them, but both are the same): M3 & M4: S1DD, WP-PCS1DRC
3. Power Supply Board: M2, S1PP, WP-PCSIPC
ANY help on this would be greatly appreciated.
Thank you,
Steve
After more research, I found where the input caps on input daughter board are known to fail. Taking a closer look at the caps, there are a few that have horrible corrosion on the solder pads and what looks to be a clear oily liquid running out and down the back side of the board from behind a couple of them. This would explain why the opamp outputs are different - one is getting a reduced signal on the front end.
Does anyone know if the this person is still offering the cards or cards for this amp?
Jason Gibson
Service Manager
Freeman’s Car Stereo
6500 East Independence Blvd.
Charlotte, NC 28212
(704)-398-2206
Does anyone know if the this person is still offering the cards or cards for this amp?
Jason Gibson
Service Manager
Freeman’s Car Stereo
6500 East Independence Blvd.
Charlotte, NC 28212
(704)-398-2206
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