Problem im having is the relay will not enguage ..
The diode tests fine that sits next to it ..
I cant seem to find the fault Anyone have any ideas?
The diode tests fine that sits next to it ..
I cant seem to find the fault Anyone have any ideas?
I'm assuming that you have already confirmed that the power supply is operating and the amp has both ±rail voltage and ±regulated 15v.
With a multimeter (unless you have your scope set up), do you have DC voltage (more than a fraction of a volt) on the emitter legs of the output transistors in either channel?
If not, drive signal into the amp and see if you have audio on the emitter legs of the outputs.
With a multimeter (unless you have your scope set up), do you have DC voltage (more than a fraction of a volt) on the emitter legs of the output transistors in either channel?
If not, drive signal into the amp and see if you have audio on the emitter legs of the outputs.
Yes in one of the channels i have 35 volts on all 3 legs of one output and -35 volts on all 3 legs of the other output ..
I pulled the outputs in that channel and still get 35 volts on the pads
I pulled the outputs in that channel and still get 35 volts on the pads
If you have 35v on the emitter of one output and negative 35v on the emitter of the other output, how can you have the emitter resistors within tolerance and not have excessive current draw. That would be 70v across 0.2 ohms. Do you have a break between the emitters and the emitter resistors?
Reflowed some solder and here is what i have on the pads for the outputs..
2SA1673
Leg 1:-33.79
Leg 2:-34.67
Leg 3:0.35
2SC4388
Leg 1:-33.07
Leg 2:35.30
Leg 3:0.36
I get these voltages on both channels outputs.. the amp is blowing outputs if left on over a min
2SA1673
Leg 1:-33.79
Leg 2:-34.67
Leg 3:0.35
2SC4388
Leg 1:-33.07
Leg 2:35.30
Leg 3:0.36
I get these voltages on both channels outputs.. the amp is blowing outputs if left on over a min
with all of the outputs out of the amp for both channels i still get the same voltages on the pads for the outputs..
I also get 35 volts on both legs of the power led and 35 volts on 2 terminals of the relay..
Any ideas ?
I also get 35 volts on both legs of the power led and 35 volts on 2 terminals of the relay..
Any ideas ?
How can you explain that the base of a PNP transistor was 35v below the emitter? The emitter follows within about 1/2v in a good transistor.
There are no outputs in the amp right now ..
Here is what i get on the pads
2SA1673 Q126 location
Base:-34.03
Collector:-34.97
Emitter :0.37
Here is what i get for the 2SC4388 location Q124
Base :-33.07
Collector:35.35
Emitter:0.36
Once again there are no outputs in this amp this is what i get on the pads for the outputs..
Both channels have the same readings on the pads
Here is what i get on the pads
2SA1673 Q126 location
Base:-34.03
Collector:-34.97
Emitter :0.37
Here is what i get for the 2SC4388 location Q124
Base :-33.07
Collector:35.35
Emitter:0.36
Once again there are no outputs in this amp this is what i get on the pads for the outputs..
Both channels have the same readings on the pads
With the outputs out of the amp, voltage readings on the pads for the outputs is generally meaningless.
With new outputs installed here is what i get
2SA
Base:-0.48
Collector:-35.32
Emitter:0.00
2SC
Base:0.45
Collector:35.33
Emitter:0.00
relay still does not enguage
2SA
Base:-0.48
Collector:-35.32
Emitter:0.00
2SC
Base:0.45
Collector:35.33
Emitter:0.00
relay still does not enguage
DC voltage on all pins of IC12. Re-check after the amp is on for a minute or so. Make sure that none of the heatsink mounted components overheat while the amp is powered up.
- Status
- Not open for further replies.