CS8414 receiver problems

[Skorpio]

I have a DAC where the lock indicator wont light up and no output. The problem is with both Coax and optical input.

Receiver is CS8414

[Skorpio]

How would be the best way to check the functionallity of the CS8414 chiip?

[hifimaker]

The problem might be with the settings of M0 to M3 which program the cs8414 for the type of clock signal. If your source is a CD player with SPDIF, check to make sure the settings are "right justified 16-bit".

-David

[Skorpio]

Thank you David, I will try to follow your lead....

[Ardee]

The lock indicator just shows whether the PLL is locked to the incoming data, so the first thing to do is to use an oscilloscope to check that the SPDIF signal is reaching the CS8414 RX pins. If it is, check that the analogue power is present, and that the PLL components are still connected.

[Skorpio]

The DAC is a Northstar DAC 3 and it has both optical and coax input, but no switch between them, it must be done automatically?

There is also a seperate clockgenerator, but the crystal frequency is 6.144MHz, and I don't understand why?

There is a PIC16C inside, probertly for changing the input value on the CS8414?

Hmmm....

[Ardee]

Skorpio,

You need to take a logical approach when fault-finding. If you do not have a schematic for the DAC, you will have to use what information there is. You have the CS8414 data, so the first thing to do is check the input to this chip. If the signal is there, then check the outputs: if not, trace it back. The 8414 is designed for hardware setup, so the PIC cannot do much to it.

I assume you have already checked that the power supplies are all OK.

You do not need to know how the inputs are switched if the signal is already getting to the chip.

[Skorpio]

All PSU voltages are ok, also on the chips.....

I only have a multimeter, so I can't measure the input to the CS8414 and the same for the output.

I have mesered the control outputs from the chip (E0, E1, E2) and they read "no lock"....(all high)

[Skorpio]

I have now measured all relevant signals on the CS8414 and found some interesting:

The F0, F1 and F2 signals are only at 2V level DC and 1V/41khz AC...and I can find the same levels on the PIC16 pins (outputs?).

It seems that the PIC don't decide between low and high?

The PIC has a resonator 4MHz and on the osilator oins I measures 2.2V dc

Perhaps I should try to hardwire the CS8414?

[Ardee]

I think you are wasting your time without an oscilloscope and a logical mind. The F0- F2 pins display the incoming sample rate by using the 6+Mhz oscillator as a reference. Presumably, the PIC displays a lock signal if this data is valid. If you cannot even show that the input signal is reaching the CS8414, you will have to rely on luck to find the fault. Sorry.