miki
New Member
Posts: 2
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Post by miki on Apr 28, 2021 12:52:25 GMT
We recently acquired a NSM Firebird which worked just fine. After about 2 weeks of operation, the sound is suddenly gone completely. Tried connecting different speakers, to no avail. (Please note: we don't have a remote for it - so mute button could not be pressed by mistake).
Also the title display gripper does not move properly anymore - sometimes only moves 1/3 or half of the way.
Any ideas what could have happened here? Did not do anything apart from connecting speakers and changing title pages.
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miki
New Member
Posts: 2
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Post by miki on Apr 28, 2021 17:51:39 GMT
OK - title display is fixed.
Still no idea what caused sudded loss of sound
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Post by jukenorman on Apr 28, 2021 19:22:33 GMT
I don't get involved with these very often but when I do, the first thing that I check is that the DC voltages are all present.
Norman.
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Post by Hildegard on Apr 28, 2021 20:30:59 GMT
The service manual for Firebird gives this informtion which might be helpful for your problem too: To protect the amplifier, a check is made whether an overload occurs due to mismatching in 250 ms cycles. Upon recognition of an error the vloume of corresponding channel is reduced step by step automatically by the computer until a non-critical point is reached.
Possible error causes: 1. Loudspeaker mismatch (less than 2 Ohms impedance) due to remote speaker
2. Transistor T252 defective
3. Output transistor defective
4. Control unit defective
If the setup wasn't changed in any way, maybe point 2 - 4 should be checked.
Hildegard
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