Audiobahn a18001dt

[Bbisig]

I just bought this amp for repair. Im really lost on this one im getting a ranging 24-34V DC on the speaker output at idle with not input or output. if nothing is hooked up to the speaker output the amp remains in protection. with a 2.7 ohm restistor on speaker out put it loads the amp(have powered through light bulb) and comes out of protection and puts out 6VDC. I have thus this far checked all the caps, output fets removed the driver card, and the four rectifiers or diodes not sure what terminalogy to use.

 

[mike49504]

With your meter set to ohms what are the readings on the outputs

Leg1-2:
Leg1-3:
Leg2-3:

You should have nothing near 0 ohms post your results

 

[Perry Babin]

Are you saying that the amp is producing 6v across the speaker terminals (measured with one probe on each of the speaker terminals) with no driver board installed?

 

[Bbisig]

mike the outputs are removed from board when producing the DC offset. Perry yes the driver card is currenly out of the board. with it out and nothing attached to the speaker output of the amp its a ranging 24-34V DC on the ouputs. with a 2.7 ohm 25 watt resistor hooked to the speaker out put then it droppes to 6V dc and will start to burn the resitor after 45-60 seconds. I do not have a scope either.

 

[Bbisig]

Also when the remote is removed the DC offset bleeds down over about 30 sec so it is storing the power in the caps.

genral pics are here
A18001DT amp pictures by brandon250mx - Photobucket

 

[Perry Babin]

If the driver board is out and it's producing DC on the outputs (measured directly across the speaker terminals), you likely have defective outputs. Either they are shorted/leaking or there is one or more with an intermittent connection on the gate leg. They often break just inside the transistor body.

 

[Bbisig]

pery the outputs are not installed in the board when all my symptoms are happening

 

[Perry Babin]

If there are no outputs in the amp and no driver board, I don't know how DC could get to the speaker terminals (measured directly across speaker terminals) unless there's a solder bridge or leakage through a contaminant on the board.

 

[Bbisig]

looks like i bought a paper weight. ill go over it once more but i do not see anything touching at all or anything on the board.

 

[Perry Babin]

It's not likely to be anything serious. Connect your multimeter and the resistor across the speaker terminals and watch the voltage while moving/pushing/pulling on various components to see if you can get the meter to change.

What is the rail voltage when you have ~6v across the speaker terminals?

 

[Bbisig]

Perry it was a solder joint. im pissed because i looked over and over for them touching. anyway all the gain controls are broken they will spin without stopping where could i purchase new ones?

 

[B.I.G]

didi u find schematics for this amp ? i have a similar one ! and i would like to have the schematics please it is a GZPA 1.4000D , a lot of amps use similar boards ...

 

[hispls]

looks like i bought a paper weight.

No offense, but that amp probably wasn't much more than that when it actually powered up and produced sound.

On the bright side, you can probably sell the heatsink for recycled aluminum and get a few bucks out of it.

 

[Perry Babin]

That's not very helpful.