Hifonics Gen X Boltar

[mike49504]

This amp powers up fine and idles perfectly for about 1- 2 mins and plays audio but with a buzzing sound heard through the speaker.. After the 1-2 mins the amp will draw excessive current and still play audio and the buzz goes away..

All ive done to the amp is replace the reverse polarity diode since it was defective..


Any ideas on where to start looking??

[Perry Babin]

Is the buzzing there without present without an input signal (RCAs connected?, no RCAs connected?)?

[mike49504]

Ok now i see why there is a buzzing sound..

On the Left channel with no RCA's plugged in I get 1.33 volts on the output terminals

On the Right channel I get -1.33 volts on the output terminals..

[Perry Babin]

How did you measure the voltage? Place the black meter probe on the secondary center tap or one of the non-bridging speaker terminals. Place the red meter probe on the bridging terminal of each channel. Do you read positive voltage on both channels?

Does the amp start to draw excessive current if left idling?

Were the transistors tightly clamped to the heatsink when the amp began drawing excessive current?

[mike49504]

Ok fixed the voltage problem on the channels i found a bad 2.7 ohm resistor that was out of tolarance... With no rca's plugged in i get no buzzing sound at all through the speakers.. only when rca's are plugged in

[mike49504]

yes the transistors were clammped to the heatsink.. It will only start drawing current after a min or 2 when everything in in the heatsink..

I let it idle out of the sink and it idles fine only had it powerd up for about a min due to the transistors for the swinger are getting hot..

[Perry Babin]

Swinger?

Were the bias transistors on the sink?

Did the current increase in both channels?

Defective insulators?

[raresvintea]

Bad post!

[mike49504]

on the board it says swinger and there is a C2238 transistor in the location.

Dont know what it means but thats what it says on the circuit board..