Lightning and CDP's don't mix

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Recently, lightning struck the service wire to our house, and one of the casualties was our CD player. Using the sevice manual as a guide, I think I have isolated the problem to the DAC, as I can get a digital signal to another DAC and sound results. The power supply is fine, and DC off-set at the output is < 3 mV. So far I have only found and replaced one bad transistor; all others tested okay. I replaced 4 IC's that could have been damaged (I could not test them) that had something to do with the analog section, muting circuit, or DAC. The DAC itself is a Burr-Brown PCM1716. There is a faint sound if I turn up the volume all the way.

Could a damaged DAC still put out a little sound?

The DAC is surface mounted (soldered) with 28 very small leads. What would I need to replace this chip? is it feasible to do by hand?
 
Thanks for the advice.

Since posting the original message, I found out what is involved in replacing the DAC chip, and I will not do it myself, as I figured I would probably ruin the PCB using ordinary tools, and it is not worth investing in special tools for just one chip.

As for the output stage, I checked all of the active devices in it and the muting circuit (transistors, opamps), and only found one bad transitor in the muting circuit. All of the voltage regulators in the powers supply are fine.

I think I will send it out for repair.
 
The ARCAM repair center found that the DAC chip was probably ok, but the "motherboard was corrupt", and it is not available anymore. The only chip I did not replace related to the DAC was a contoller. I figured it was okay as the transport and remote functioned fine, but part of this chip controls the DAC. The ARCAM repair folks tested the transport section and said it was good.

Anyway, I would like to install a DAC in the ARCAM case by using the existing regulated power supply and audio section. The unit has a provision for an upgrade DAC (not available either) so the connections are a little easier than cutting traces etc. The digital output is SPDIF and it goes through an isolating transformer. I plan on shielding the DAC unit.

Is there a basic problem with this approach? I have the repair manual and schematic, and will try the RAKK DAC if it fits. Does anyone know the dimensions of the original RAKK DAC?

I asked Kevin at K & K Audio about this, and he recommended against installing one and suggested I buy the Mk II DAC, PS, and line stage and build an external DAC. This could be simpler, but much more expensive.

What do I have to lose by trying to patch in a DAC? The main difference between this and an external box seems to be location.
 
I wouldn't take the "corrupt motherboard" diagnosis very seriously. Have someone else look at it. Maybe someone from this board in your area?

Installing a complete external dac inside the CDP case is certainly possible but from my POV it's simply wrong. External dacs have spdif inputs and using those is (maybe) acceptable for an external dac but there is just no excuse to do it inside a CDP. Try to identify I2S signals and format for your dac and you'll stand a chance to end up with a good sounding CDP again.

Still, rather repair it than create a Frankenstein.
 
Thanks for the advice. The "corrupted motherboard" comment came from Charley Croan at ARCAM in the UK when the ARCAM repair center asked for help, so it may have some credence. I live in SE Idaho -- is there anyone on this board near me?

It may be difficult to get I2S signals out of the disc drive unit as the manual only mentions SPDIF coming out of the decoder.

What's the disadvantage of SPDIF compared to I2S?
 
Hi,

What test equipment do you have to diagnose the problem ? An oscillosope and logic analyser would be useful !

When you say faint sound is that music or noise? If it's music then I'd look at the output stage again.

I'm not sure if anyone does a U bit to desolder all 28 pins in one go ? There are methods of removing SMT ICs using a pair of tweezers a very sharp knife and a soldering iron but they risk damage to the pcb and destruction of the IC. I'd use solder wick and a pair of tweezers myself but I wouldn't recommend it to someone who isn't confident with a soldering iron !

Cheers,

Jon
 
SMT replacement

It must be a special CD player to just not go out and buy a new one.

One of my buddies unsolders SMT ICs by adding a little solder blob to a pin and the while the solder is liquid bending the lead up with a fine but strong dental pick / tool.

I don't remember if he does the corner pins last or not.
 
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