To little voltage to power amps, help!

[Rohner 10+ year member]

I've got a problem with my system, and have no idea how to fix it. I tried messing around a little today and have had no luck. I'll try my best to explain what iv done so far and what's happening.

My amps havnt been powering up for 6 months now, and i decided to get my truck thumping again so i went out and bought a new HU thinking that the old one i had wasnt sending a remote signal to power up the amps. So, i installed the HU today and the amps are still not powering. I bought a multi meter and took a reading off of my battery, and its reading 13V. I took a reading off of the amp with the power/ground connected and it only read 1.88V. So i disconnected the power wire and took a reading off of it and it reads 13V. So basicly when its hooked up to the amp the voltage drops and is not giving it enough power to turn on.

I turned off the HU and hooked up the voltmeter to the amp and to voltage increase slowly untill it reached approx 12 volts. but as soon as i turn the HU back on the voltage drops to 2V.

I decided to rip out the power wire and run a new one out of a spare piece i had kicken around, it read 13 volts WHILE connected to the amp. So i turn the key over and the amp powered up, and played music for about 15 seconds before shutting off. Now im back to square one. I took a reading off the amp again and its still only reading 1.8-2.3V.

I tried the same thing with my other amp (for the speakers) and am having the same problem.

Any ideas why the voltage is dropping so much that it wont even turn the amps on? need help ASAP, any recomendations or ideas would be awsome.

Also- The ground is fine, its reading 0 ohms, so were good in that department.

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[Rohner 10+ year member]

no ideas?

 

[ultimate157 5,000+ posts]

No way you're getting 0 ohms ... I would check your grounds.

 

[Decipha 10+ year member]

try using a different ground, also connect the remote directly to the +12

 

[thch 10+ year member]

remove RCA's from amp. does amp power on? does amp still have 0ohm from chassis to its ground terminal? if you measure ground from the RCA shield to the ground bolt, do you get some resistance?

for it to fall that low means either excessive current draw, which would blow a fuse, or excessive resistance in +12V or gnd connection. the latter can happen if the amp's gnd terminal is not connected, and the amp is grounded through the RCA. If the 0ohm reading for gnd is from the gnd terminal to the location the wire runs to, it may be possible the wire is not connected to the chassis. if this had worked in the past, it may be prudent to reconnect the wires and clear off any corrosion that might have formed due to oxidation or dissimilar metals.

 

[helotaxi 5,000+ posts]

What type of main fuse are ayou using and have you replaced it? A bad fuse will have exactly the symptoms that you describe.

 

[Rohner 10+ year member]

so, i got it working last night. But it still seems kind of iffy because i hadnt realy changed anything. Im going to play around with it a bit at the shop to make sure it works, then ill start changeing out fuse's/ground ect.. thanks guy.

 

[Rohner 10+ year member]

well that was easy.. decided to check the inline fuse even thow it was intact looking threw the window. Turns ou tthe end cap of the fuse had detached. replaced fuse and im good to go!//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

thanks boys.

 

[helotaxi 5,000+ posts]

Amazing how the simple things will get you isn't it? Glad it was something easy.

BTW, I hate glass fuses for exactly that reason.