Fried preamps or what???

[86svo 10+ year member]

Ok, so today I was installing my F-250 alpine amp and getting things set for when my rainbow components get here tomorrow.

I have my alpine m-500 mono amp pushing my sub and been running great for the past two months, gain set at 31.6.

Today, in the midst of my wiring things up the wires behind my head unit start smoking up!! I was like WTF so I ripped out the HU and the smoking stopped. Upon further inspection of things I found that not only did my negative wire to the battery come in contact with the negative terminal, but also one of my rca wire terminal end was touching a ground for amp(no amps were in the car). The RCA terminal at the HU fried itself really good so I had to get new rcas, but the HU looked good.

Get everything wired back up and go to set my gains, 31.6 for the mono and 20 for the 4-channel (running it bridged). For the mono I could not get anything more than 4.5v and then suddenly I was able to jump back up to where I should be, only to have the volts drop back down the next time I turn the HU on. With the 4-channel I cannot get any more than 13.5v with gain turned to max.

I took the DMM and turned it to DC V set @20 (settings are either 1000m, 20, 200 or 600 on the DMM) and only recorded a reading of .06v.

I assume I was correct in changing the DMM to DC since I was taking the reading from the HU? If that's the case am I safe to assume the HU is toast and I should get another?

I just bought the HU a couple months ago from Best Buy, so I believe the waranty should be good still. Anyway, thoughts or ideas?

Thanks

Jason

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[Motley 10+ year member]

Yup, you fried something in the HU, take it back for warranty.

 

[DidUHearThat? 10+ year member]

I took the DMM and turned it to DC V set @20 (settings are either 1000m, 20, 200 or 600 on the DMM) and only recorded a reading of .06v.

Test it again set at AC with a test tone disc. Audio is mostly AC.

If it still doesn't work, try to return it to best buy and dont' tell them what happened, just say it doesn't work, you don't know why. Screw BB.

 

[86svo 10+ year member]

Well, took it back to best buy, got a new unit and everything works great now!

Next time I'll definitely make sure to secure all power cables, lol.

 

[Motley 10+ year member]

Glad it worked out. BB warranty for the win.