| OXAUDIO |
| Info. needed on the above, please - I was not sure whether to post this under 'Solid State' or 'Chip Amps' - anyhow a circuit diagram, plus info.(pin-outs & block diagram) for the RSN6000B Mosfet Module(IC502) would be helpful. I am in process of repairing an SUA900Mk2 in which the mains fuse T1 (3.15AT) had blown, the only other known fault being that D702(original type P300D) was short circuit. D 701, 03, & 04 'cold' check OK, but I have replaced all 4 with 1n5408 diodes. I don't know why one diode of 4 in the main Bridge rectifier would fail s/c, and have yet to power up and test the amp. |
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| OXAUDIO |
| Problem solved! After making some further checks, I found that the only fault was the short-circuit rectifier diode and blown mains fuse. I replaced all 4 original diodes with 1N5408s, and the blown fuse. The amplifier is now working perfectly on test as I type this, but I still do not know why ONE diode of four in a conventional Bridge Rectifier should go s/c |
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| linuxguru |
| If the failure occurred, for instance, due to an output short, then it depends on the phase of the input AC supply at the moment the short occurred. The two input rectifiers that were conducting at the time of the short are likely to fail first - in this case, one of them failed first, followed by the fuse blowing and protecting the others. That's why the others did not fail. |
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| sakis |
almost the same problem and in this case replacing all diodes is the best to do but in my case the problem started from the small ceramics togther with the diodes ...one of them failed then the diode then the fuse ....
replaced all of them...and done |
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| OXAUDIO |
| Thanks to both Linuxguru & Sakis. Must admit I hadn't thought about 'cause and effect' to quite that extent. The amplifier has now been test run for about 4 hours continuously with no repetition of the failure, so all's well that ends well |
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