pin 10 is connected to Q2 and is A1030 (if my eyes are working correctly today!)
Probably a 2SA1038.
The following suggestion could cause the amp to draw excessive current and could possibly cause the amp to be damaged. Be careful and be prepared to disconnect the amp from the power source quickly. I'd suggest that you connect a 10-15 amp fuse between the power supply and the amp. You should also clamp all transistors to the heatsink. I know it's time consuming but it will help protect the power semiconductors.
Remove Q2 (assuming that the collector is connected to pin 10). Does the amp still go into protect mode?
Does the amp draw excessive current?
The following suggestion could cause the amp to draw excessive current and could possibly cause the amp to be damaged. Be careful and be prepared to disconnect the amp from the power source quickly. I'd suggest that you connect a 10-15 amp fuse between the power supply and the amp. You should also clamp all transistors to the heatsink. I know it's time consuming but it will help protect the power semiconductors.
Remove Q2 (assuming that the collector is connected to pin 10). Does the amp still go into protect mode?
Does the amp draw excessive current?
both correct..
i removed the A1038 and at 1st the amp blew a 5amp fuse, so i fitted a 20amp and it settled out at 0.9amp which is correct for this amp.
Well, that narrows it down. Not having a scope makes it a bit more difficult. Start checking all of the transistors and resistors in that channel.
If you measure the DC voltage across the speaker terminals (black probe on the non-bridging terminal), do you read any significant DC? If so, is it positive or negative DC?
If you measure the DC voltage across the speaker terminals (black probe on the non-bridging terminal), do you read any significant DC? If so, is it positive or negative DC?
just made a discovery.. whilst checking the emitter resistors i noticed something wasn't right across a whole bank. whom ever did the solder job on the speaker cable didn't do a very good job and got a bad solder on the through holes which the speaker cable is soldered to so the tip35's on that channel were not operating correctly..
i now have clean output on both channels.
where does the A1038 come into this equation?
i now have clean output on both channels.
where does the A1038 come into this equation?
The amp was going into protect before you could determine what the fault was. From the information provided, it appeared that the fault was triggering the protection circuit through that transistor. Removing it defeated the protection circuit allowing you to see which channel had a fault. That narrowed down the search for the problem. You can reinstall it.
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