Oh. I see. Now it makes more sense. That also means that the emitter of that transistor was shorted to ground. I've marked the three terminals on the output devices and the inadvertent short circuit in the images below.
Does TR48 control the output relay by any chance? I bet the relay tripped because of excessive current (-> excessive voltage across the emitter resistors -> TR16 turns on -> TR48 turns on). Unless something is done to then power down the amp electronically, the amp is basically allowed to self-destruct. Had TR16 tugged on the drivers it could have turned the output stage off and maybe prevented the destruction. But that's not the case here.
Anyway. I bet you can get it working. It shouldn't be too much hassle to replace the transistors as I described above. Best of luck.
Tom
Does TR48 control the output relay by any chance? I bet the relay tripped because of excessive current (-> excessive voltage across the emitter resistors -> TR16 turns on -> TR48 turns on). Unless something is done to then power down the amp electronically, the amp is basically allowed to self-destruct. Had TR16 tugged on the drivers it could have turned the output stage off and maybe prevented the destruction. But that's not the case here.
Anyway. I bet you can get it working. It shouldn't be too much hassle to replace the transistors as I described above. Best of luck.
Tom
Just beware of fakes. Buy from a distributor like RS, Farnell, Mouser, Digikey. Not from ePay.
Tom
Doesn't look like you are going to make any progress until you decide to share the schematic with one or more people. Otherwise its a waste of time guessing game that has failed to be productive so far.
If I were to share it with someone and then they share it I could then potentially be responsible for getting the Restek employee in trouble or worse lose his job and I don’t want that on my conscience. I appreciate everyone trying to help.
Okay, fair enough. However...since (1) you don't know how to use the schematic, and since (2) protecting the Restek employee is of the utmost importance here, then (3) wouldn't the safest thing to do be to burn the schematic and be done with it?
I mean, its doing you no good at all, and just having it in the first place is already a big enough risk to the Restek employee, right? So, what else would you do with it anyway? Store it with boxes of old newspaper clippings and stuff?
Okay... Maybe I'm being a bit silly here, but aren't you as well?
I mean, its doing you no good at all, and just having it in the first place is already a big enough risk to the Restek employee, right? So, what else would you do with it anyway? Store it with boxes of old newspaper clippings and stuff?
Okay... Maybe I'm being a bit silly here, but aren't you as well?
You will have to remove the shorted transistor and test the other 3 for shorts. Only 1 channel should be affected. Check the driver transistors as well.
Or even just place it on a shelf and wait for a better time financially, and know you did your best, didn’t make anything worse.
Might actually be saving money that way.
Hats off to the fine people who helped so far however, is always nice to get a hand when you need one.
Might actually be saving money that way.
Hats off to the fine people who helped so far however, is always nice to get a hand when you need one.