lumanauw said:I've got a friend who has a dead Studer A730. I'm not familiar with digital, but is it possible to fix this CD player? What to check first?
If you can use it lumanauw,
ftp://ftp.studer.ch/Public/Products/CD/A730/Manuals/
Cheers George
Hi, Everybody,
Thanks for the inputs
Thanks, Georgehifi. That is one big file, 59Mb
From quick check, all the fuses are OK (2 fuses are inside the AC plug-in, 4 fuses inside the unit).
I found something strange. The voltages at opamp rails are not symmetrical, +11Vdc (pin8) and -14Vdc (pin4).
Thanks for the inputs
Thanks, Georgehifi. That is one big file, 59Mb
From quick check, all the fuses are OK (2 fuses are inside the AC plug-in, 4 fuses inside the unit).
I found something strange. The voltages at opamp rails are not symmetrical, +11Vdc (pin8) and -14Vdc (pin4).
Hi, Everybody,
I've looked more closely through the dead StuderA730.
-From outside panel (keyboard) not 1 single LED is on. All LEDs and 7segments are off, no matter what button I push, nothing happens.
-If I put a CD inside the tray, the CD spins, but no LED or 7segments is on. All indicators are dead.
-All the fuses are OK, the DC voltages from power supply are all present and normal. 2 LEDs are illuminating inside the unit, one red LED and 1 green LED on the right-down corner.
-The power supply heatsink (a piece of aluminum sheet) is a bit hot.
-There's an IC with code SAA7220 (position near TP5-TP6) is very hot. Is this normal? From the datasheet it is a digital filter IC.
Here's voltage measurement on Test Points (TP) as I measured them VS as written in the service manual.
I measure the voltage in dead condition, the service manual said the voltages are in "play mode", so could be different.
Anyone can help to interprete what is going on?
I've looked more closely through the dead StuderA730.
-From outside panel (keyboard) not 1 single LED is on. All LEDs and 7segments are off, no matter what button I push, nothing happens.
-If I put a CD inside the tray, the CD spins, but no LED or 7segments is on. All indicators are dead.
-All the fuses are OK, the DC voltages from power supply are all present and normal. 2 LEDs are illuminating inside the unit, one red LED and 1 green LED on the right-down corner.
-The power supply heatsink (a piece of aluminum sheet) is a bit hot.
-There's an IC with code SAA7220 (position near TP5-TP6) is very hot. Is this normal? From the datasheet it is a digital filter IC.
Here's voltage measurement on Test Points (TP) as I measured them VS as written in the service manual.
I measure the voltage in dead condition, the service manual said the voltages are in "play mode", so could be different.
Anyone can help to interprete what is going on?
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