I have problem with this driver card. Many times I have defective transistors (2sc411) which drives the output relays.
Do someone use any other case transistors in their place? Or search for relays with bigger coil resistance?
Those are a pretty hefty transistor. Does the relay have a snubber diode across its coil ?
If you mean these are failing on many units then that points to a design issue... and that could even be a layout/wiring/ground wire issue that causes some unexpected spike as the transistor (or something else) switches. What I'm getting at is that its not necessarily a transistor problem, there could be some external reason. Any dries anywhere ?
If you mean these are failing on many units then that points to a design issue... and that could even be a layout/wiring/ground wire issue that causes some unexpected spike as the transistor (or something else) switches. What I'm getting at is that its not necessarily a transistor problem, there could be some external reason. Any dries anywhere ?
Yes, sorry, BR (2SC2412). It does have diode across coil.
I am not sure if its design issue (Perry can comment about it more), but its third amp with the same problem in relatively short time.
One was already repaired by me and replaced with original one.
I am not sure if its design issue (Perry can comment about it more), but its third amp with the same problem in relatively short time.
One was already repaired by me and replaced with original one.
I've seen them fail but it's not often. When either Q4 or Q5 fails, I replace both.
Check R5 also. You'll have to remove it to check it.
Check R5 also. You'll have to remove it to check it.
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