Connect the amp to positive, ground and remote in, also speakers. So basically only 3 wires to the car or only two if you bridge remote to positive.
Connect your phone or any external signal source, not connected to the car, to the input. Play music, then start the car. Still noise? Amp has a problem. No noise, you got some ground loop in your car installation.
I know that this test is hated, because it is so simple and has only one and definite diagnosis out of two. That's why people always avoid it.
I have been doing car HIFI for decades, noise because of self build faults is the number one problem. I don't waste my time by ignoring the most simple measures and tests.
Like doing a secondary earth wire from battery to engine and chassis.
Connect your phone or any external signal source, not connected to the car, to the input. Play music, then start the car. Still noise? Amp has a problem. No noise, you got some ground loop in your car installation.
I know that this test is hated, because it is so simple and has only one and definite diagnosis out of two. That's why people always avoid it.
I have been doing car HIFI for decades, noise because of self build faults is the number one problem. I don't waste my time by ignoring the most simple measures and tests.
Like doing a secondary earth wire from battery to engine and chassis.
Get the diagram from Rockford but as far as I know, one of those diodes connects between the RCA shields and the primary ground. How could you read 0 ohms from the shields to the primary ground but not across one of those diodes?
I didn't see many (any?) RF series amps. Email or call Rockford to get the diagram for your amp.
Well, I decided to take another stab at fixing this awesome amp.
Unfortunately, while I wasn't able to get a diagram from those suckers, I DID find a THIRD ED D5 diode that WAS shorted (diode D13). I unsoldered it and tested it outside the circuit and sure enough, I got continuity both directions through it. It also connects the rca shields to the ground. I tested the resistance between the ground and the rca shield with the shorted diode removed and get 0.966 kiloohms (with a fluke 117 multimeter). NO beep on the continuity/diode check this time.
I think that's what was causing the zero ohm resistance I had earlier. Perry, thank you for getting me on the right track. Is there anything else I need to check?
Unfortunately, while I wasn't able to get a diagram from those suckers, I DID find a THIRD ED D5 diode that WAS shorted (diode D13). I unsoldered it and tested it outside the circuit and sure enough, I got continuity both directions through it. It also connects the rca shields to the ground. I tested the resistance between the ground and the rca shield with the shorted diode removed and get 0.966 kiloohms (with a fluke 117 multimeter). NO beep on the continuity/diode check this time.
I think that's what was causing the zero ohm resistance I had earlier. Perry, thank you for getting me on the right track. Is there anything else I need to check?
This isn't much help now but with the added information of D13 and knowing what it was (and causing engine noise), that lead me to the attached diagram.
Thank you for the diagram (I contacted Rockford a few times for it but got no reply). I'll look it over carefully. I will need to replace that bad diode for starters, though.
If you don't have the identical diode on hand and want to try the amp, any rectifier diode will work. If you have some 1N400x diodes, you can use one for testing.
Thank you. I'll have to do that for now. I'm not able to find any with those "ED D5" markings. I'm having a hard time reading the diagram because of the low resolution, though.
In post #26 it's the original PDF file from Rockford. Some of their diagrams are garbage but this one is clean. Download and view in a PDF reader like PDF X-change Viewer (not editor).
https://www.majorgeeks.com/files/details/pdf_xchange_viewer.html
https://www.majorgeeks.com/files/details/pdf_xchange_viewer.html
I was opening the file on my phone and it looked crappy. I opened it on my desktop and it looks way better.
I'm an oddball when it comes to phones. I use it about 3 minutes a year. It's a $20 (new) flip phone and generally only gets used as a timer so I don't forget to take something out of the freezer. On tracfone, I have more than 14k talk minutes and more than 26k text messages on rollover.
Unfortunately I need my phone for work in order to clock in or out. As far as computers, I'm an oddball in the fact that I refuse to use lousy Microsoft products or even Apple. My Linux Mint desktop opened the diagram you attached out of the box.
WIn7, 12 year old (newest) computers and they do everything I need them to do and are rock-solid stable. I hope this repair is done. I don't want to get a nasty message from myself for contaminating a repair thread.
No worries. I'll find out when I hook the amp up to my vehicle and start the engine and moment of truth I hear no whine. It's dark right now. I tested the amp on a power supply and it works well, no magic smoke.
I'm happy to report that my alternator whine is GONE after hooking it up to my running car. This old amp can now have a new life not collecting dust for once. Many thanks to Perry Babin and everyone else here for the help.
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