Something pretty drastic has happened there...
OK, how to identify an unknown.
How many legs has (or had
) it ? Are we going for three and that its possibly a transistor ?
Note the position of the device as fitted and remove it. Does any pad go to ground ? Yes, no ? Does any pad go to a supply ? Yes, no. Does any pad appear to have a high impedance leading to it... that could signify a base or gate of a transistor. Power the device up with the part removed. Identify which pad has the highest and lowest voltages. Scope the pads. See if any has a "drive" or control signal present. The amplitude and polarity of that (if present) should be a good guide as to whether it was an NPN or PNP device or even an N or P channel FET.
And it would help to know what the unit is
OK, how to identify an unknown.
How many legs has (or had
) it ? Are we going for three and that its possibly a transistor ?Note the position of the device as fitted and remove it. Does any pad go to ground ? Yes, no ? Does any pad go to a supply ? Yes, no. Does any pad appear to have a high impedance leading to it... that could signify a base or gate of a transistor. Power the device up with the part removed. Identify which pad has the highest and lowest voltages. Scope the pads. See if any has a "drive" or control signal present. The amplitude and polarity of that (if present) should be a good guide as to whether it was an NPN or PNP device or even an N or P channel FET.
And it would help to know what the unit is
Assuming it's part of the amplifier, it's very likely lot's of other parts have died as well.
Can you post a latrger picture, showing more of the board?.
You can see half the Fairchild "F" in the top left hand corner. (if I'm not mistaken.)
I looked at a couple of Fairchild TO-92s on my desk and they have the date code on the top row.
If your transistor is the same, then 852 is the date it was manufactured.
Like Mooly said, you can either trace out the circuit and figure out what kind of transistor would be appropriate in that position, or find an identical unit and identify the transistor from there.
I looked at a couple of Fairchild TO-92s on my desk and they have the date code on the top row.
If your transistor is the same, then 852 is the date it was manufactured.
Like Mooly said, you can either trace out the circuit and figure out what kind of transistor would be appropriate in that position, or find an identical unit and identify the transistor from there.
Ok, this may be a shot in the dark, but there is another poster with a BASH amp problem
http://www.diyaudio.com/forums/soli...sh-amp-class-h-repair-advice.html#post4120393
If they are similar enough, maybe you can help each other out.
http://www.diyaudio.com/forums/soli...sh-amp-class-h-repair-advice.html#post4120393
If they are similar enough, maybe you can help each other out.
Well the other night I put a blanket down on the ground to play with my newborn across the room from where I was attempting repairs and saw a little black speck on the floor. Picked it up and was all LOLOMG. It was the piece of blown apart transistor. Could clearly read that is was a 4401. So picked one up today and replaced it.
Low and behold the amp pops the fuse upon pluging it in to the wall. So obviously I did more damage than just the one transistor. I just can't believe I actually repaired the damn thing finally. Then just after finishing I slip up and kill it all over again.
I just don't have the skill to fix it at this point. I think it's time to toss it in the garbage even after all the time I spent on it
Low and behold the amp pops the fuse upon pluging it in to the wall. So obviously I did more damage than just the one transistor. I just can't believe I actually repaired the damn thing finally. Then just after finishing I slip up and kill it all over again.
I just don't have the skill to fix it at this point. I think it's time to toss it in the garbage even after all the time I spent on it
Thank you ashok.
I usually don’t post in DIYAudio because there are those here that seem to survive for the only purpose of being able to contest literally whatsoever and I just won’t give them any fodder.
I was really tired last night so I didn’t further mention anything although as I now look at it again I am still not certain if there is yet another issue on the switcher board.
There is thermal debris smattering the side of the windings of the toroid transformer directly adjacent to Q3 and Q4.
Q3 and Q4 together with the PC board look like they are heat discolored in this region and it also looks as if the neighboring fusible link could be cracked as well.
Its difficult to tell from just a picture but something became quite hot to concentrate the deposit of that debris on one side the transformer windings.
Again, the best of luck to you.
Rich B.
I usually don’t post in DIYAudio because there are those here that seem to survive for the only purpose of being able to contest literally whatsoever and I just won’t give them any fodder.
I was really tired last night so I didn’t further mention anything although as I now look at it again I am still not certain if there is yet another issue on the switcher board.
There is thermal debris smattering the side of the windings of the toroid transformer directly adjacent to Q3 and Q4.
Q3 and Q4 together with the PC board look like they are heat discolored in this region and it also looks as if the neighboring fusible link could be cracked as well.
Its difficult to tell from just a picture but something became quite hot to concentrate the deposit of that debris on one side the transformer windings.
Again, the best of luck to you.
Rich B.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.