ARCAM Alpha 5 PLUS CD PLAYER
- Thread starter Keith7
- Start date
Yes, almost certainly fixable.
The digital output being live means *everything* up to the SAA7220A digital filter is working Fine. After that for the analogue outputs is the TDA1541A dac, and the analogue filter stage consisting of OP27 opamp doing I-V conversion and NE5532 in the output filter.
First place to check would be to use a voltmeter to ensure all these chips are getting their required supplies. Measured w.r.t 0v (output jack 0v will do):
TDA 1541A:
+5v on pin 28
-5v on pin 26
-15v on pin 15
Opamps should have +/-15v on pins 7 and 4 respectively.
All voltages even within -/+1 v or more (!) of these nominal values will work fine - just take care not to inadvertently short pins with the probe when testing!
If those rails are all in place it's probably time to look at the muting circuit, esp if it is sudden death on both channels (ie not one gone 'off'').
I can email you a copy of the service manual if you drop me a PM with email addy...
The digital output being live means *everything* up to the SAA7220A digital filter is working Fine. After that for the analogue outputs is the TDA1541A dac, and the analogue filter stage consisting of OP27 opamp doing I-V conversion and NE5532 in the output filter.
First place to check would be to use a voltmeter to ensure all these chips are getting their required supplies. Measured w.r.t 0v (output jack 0v will do):
TDA 1541A:
+5v on pin 28
-5v on pin 26
-15v on pin 15
Opamps should have +/-15v on pins 7 and 4 respectively.
All voltages even within -/+1 v or more (!) of these nominal values will work fine - just take care not to inadvertently short pins with the probe when testing!
If those rails are all in place it's probably time to look at the muting circuit, esp if it is sudden death on both channels (ie not one gone 'off'').
I can email you a copy of the service manual if you drop me a PM with email addy...
Thanks, Felix. That would be great if you could email a copy of the service manual. [email protected]
Much appreciated!
Much appreciated!
