⟐ Commented July 01, 2025 at 5:54 MST

⟐ Commented June 02, 2025 at 21:10 MST

My sister's car -- namely, the car's sub amplifier -- is giving me all sorts of sass. I'm trying to diagnose it from a world away (she's in Tennessee, I'm in California) and it just does not want to work properly.

A bit of background: I sent her my old subwoofer and amplifier because her setup stopped working awhile back, and she was unable to take her old sub+amp up to Tennessee when she moved anyway. So, I shipped her my sub+amp in "known good" condition, and my amp just flat-out refused to work. It powered on briefly (the yellow LED on the amp itself turned on, but not the green LED on the subwoofer level controller), but turned off as soon as she hooked up to sub... And then it never powered back on again.

So after some brief multi-metering, we chalk it up to a bad amp and she orders this Boss amp from Amazon.

Yesterday the amp arrived, and we're back to square one. These are her installation pictures: pic #1 and pic #2. Please refer to them, as I will be using the specific names found on the amp. This is what I know, according to sister:

• The green Power LED is lit, and the Protection light is *not* lit.
• Batt+ and Ground have 12.8ish volts across them when measured with a multimeter.
• Remote and Ground have some negligible voltage across them when measured with a multimeter (and the radio is on) -- but that voltage goes away when the radio is turned off. So I'm assuming that the amp gets a signal from the radio to turn on.
• Speaker Connections have 0 voltage across them.
• I had her test the continuity of the sub by measuring across the subwoofer terminals. Since the multimeter doesn't have a "continuity test" mode, I had her do the old-school Ohm method -- setting the meter to 200 Ohms. With multimeter leads not touching, the multimeter reads 1 Ohm. With leads touching, it changes to 0.1. So touching something that has continuity should change it to 0.1. She tried this on the 30 amp fuse on her old amp, and the method worked (the multimeter changed to 0.1). However, when she puts the leads on the subwoofer terminals, no change happens. But if she connects the speaker cables from the amp to the sub and performs the same test, the multimeter reads 0.1.

So that's where we're at. I basically have three questions:

1. Should the Speaker Connections read 0V across them? I thought that there should be some voltage coming out of those terminals that would indicate that sound was being output.
2. Piggy-backing on the previous question, I'm curious if there would be any voltage coming out of the Speaker Connections if the RCA audio jacks were bad (basically the audio signal coming from the radio). So a) would there still be a voltage coming through Speaker Connections, and b) does anyone know of a good way to test if an audio signal is coming from the radio through the RCA jacks? I would have her do the Ohm method for continuity, except the opposite ends of the jacks are like 15 feet away, one side being by the radio, the other in the hatchback area.
3. Should the multimeter Ohm reading change when she measures the subwoofer terminals? As far as I recall, the sub is wired in parallel internally (it's a dual coil Rockford Fosgate Punch HE2), but I assume that it should still read some resistance value that is not 1. I figure that even if the sub had tons of resistance, the multimeter reading should spike to some other value, since the multimeter was put on the lowest possible Ohm setting.

The issue is that the sub is encased in a completely sealed enclosure, and she'd have to tear the whole thing apart in order to ensure the wiring is fine. So I'd love to be able to *not* have her do that if at all possible.

Thanks in advance!

⟐ Commented September 12, 2021 at 21:14 MST

At this point, the stereo doesn't send any signal to the speakers. The unit powers on and reads CD's just fine, but refuses to make any kind of sound. Any ideas?

⟐ Commented June 19, 2024 at 1:38 MST

input ac120v 60hz

output dc12v 500ma

what should I buy

I need to buy an ac/dc adapter, an extension cord is not going to do the trick. I need to know what kind on voltage and output I need. The converter/adapter is lost . I would like to save the unit but do not know what size adapter to buy

This a battery jump pack that is used to jump start a car. Some units have an ac adapter built in so you can charge the battery in the jump start pack. My unit has a spot to connect the ac adapter to the jump pack so you can charge the battery in the jump pack. My ac adapter has been lost. I know I have to buy a new ac adapter so I can charge my jump pack, what I do not know is if the input (from the ac adapter) is 120v 60 hz

I understand that the DC output needs to dc12v. I do not understand the milliamps. The battery in the jump box is 12v 10 ah ( what ever that is). I just want a new ac adapter to charge the jump pack with that is not going to damage anything.

⟐ Commented June 18, 2024 at 10:44 MST

I am thinking of tweaking Xiaomi Roidmi 2S a bit because it has rather low quality microphone build in. I'd like to solder a 3.5 jack socket and that way attach a small directional external mic.

But I don't know how to disassemble this device :)

Can anyone help?

A perfection would be to put it step by step on YT.

⟐ Answered March 03, 2018 at 15:40 MST

Everything works except the backup camera display is black. When I put it in reverse the H/U switches to backup camera mode and it says "image may be reversed" and shows the parking assist lines. I move the gear selector either way and the H/U goes back to regular mode.

I know the camera works when i put it in reverse because I have a separate video monitor it displays on. It turns on when I select reverse and off when I select another gear.

-head unit works

-camera works

-reverse triggers a backup screen

-screen is black with warning message

-backup lines show

-hooked into brown port "r/c in"

⟐ Answer edited February 10, 2026 at 4:41 MST

⟐ Commented January 19, 2025 at 20:59 MST

It seems like a giant waste to only be able to use it in the car - is there any way I can adapt them to use with my TV or computer? Perhaps with a bluetooth adpater

⟐ Answer edited May 15, 2020 at 8:47 MST

Well, I can't seem to get any of them to work. I just finished trying for the 6th time.... I think there may be a wiring mistake I'm making, or else there is supposed to be a SMD resistor between pins 4 and 5 (at least 200 ohms?).

Can somebody help me out and tell me what I'm doing wrong? I always test after finishing, +5VDC between pin 1 and 4 or 5.... I've tried jumping pins 4 and 5 as well as wiring to each individually.... the phones charging indicator doesn't say it's charging, but the phone does recognize it being plugged in. When I was trying only pin 1 and 4, the phone indicated that a USB cable was plugged in...

Thanks in advance!

⟐ Commented February 19, 2021 at 12:32 MST

⟐ Commented October 06, 2020 at 14:38 MST

It's not limited to only one disc, and sometimes it will spit one particular disc out, and sometimes the same disc will get stuck, as it were.

⟐ Commented October 11, 2018 at 6:28 MST

⟐ Commented December 13, 2024 at 4:08 MST

⟐ Answered November 20, 2025 at 15:42 MST

⟐ Answered February 10, 2023 at 13:31 MST

⟐ Answer edited April 16, 2024 at 2:18 MST

⟐ Commented October 28, 2022 at 12:28 MST

I have the Pioneer avh-295bt

⟐ Commented November 19, 2023 at 15:57 MST

⟐ Answer edited June 17, 2023 at 9:35 MST

⟐ Commented December 15, 2022 at 23:38 MST