[NordicNorm]

Howdy All!

I've been bitten by the DIY bug once again, and so decided to try out the old school way again. I have soldered for many years (my very first projects involved Commodore 64's, just to give you some perspective), and although it has been awhile (kids, etc.), I can read circuit diagrams.

I have an Oppo 980H that I'd like to experiment on, but I can't find a schematic anywhere!?

I've read a couple of threads on here and DIYAudio regarding modding the 980 so I'm puzzled!? How do you identify the components? Does anyone have a link to a guide of some type? Any help would be appreciated (otherwise, this could be a very short lived project! ).

Thanks,
Norm

[NordicNorm]

OK, so I've identified the DAC and opamps but my original question remains: how do you go about mucking about without a schematic!? The only way I can see is manually, using a DMM and a 'scope, and trying to trace out the circuits!?  That seems a bit like thrashing around in the dark!? There must be a simpler way I'm missing?

[richidoo]

You learn by experience what is what on the circuit board. You can identify the power supply section by where the AC mains comes in, and the transformer and rectifiers. You identify the digital audio sections by the DAC chips and wires from the transport.  You identify the analog stage by the output wires or jacks soldered to the PCB. There is also a microprocessor section, and remote control, etc. Look for the ICs that correspond with each function. Google the numbers printed on the ICs to find out what they do.

Regulators like Belleson or Hynes on the DAC and output opamps offer the biggest bang for the buck. Then coupling caps at the analog output. Then analog opamps, clock, vibration damping, etc.

Read what pro modders and DIY modders are doing to your unit for guidance on the value of the various mods. Like this one:
http://www.tweakaudio.com/EVS-2/Oppo_Player_Mods.html

DIY Rule #1 = Have fun!

[NordicNorm]

Thanks for the response richidoo!

That makes sense.

Regarding Ric's tweaks, can you simply swap out the existing Oppo DAC with the 32 bit AKM 4397 DAC? I guess I'll have to study the two schematics and compare to find out!?

cheers,
Norm

[NordicNorm]

Hmmm... guess it's not a simple matter to swap out the Cirrus Logic DAC with an AKM one? The CL is 20-pin, while the AKM is 44!?

Or am I missing something obvious?

[*Scotty*]

Norm,
I would advise contacting the Oppo repair facility here in the states if there is one,and requesting a complete schematic specific to the 980H player. In all likelihood the circuit board is a four layer board. These things don't lend themselves to casual analysis even by professionals with unlimited time on their on hands because you cannot possibly see all of the interconnections between components inside the hidden layers.
 When I decided to modify my Cambridge 740C I contacted the Cambridge repair depot and the head service technician promptly sent me a complete schematic via email. He even had time to talk with me over the phone about the project.
Scotty

[richidoo]

Swapping DAC chips from different manufacturers is not a simple job, because the I/O pins will not match. So Ric has engineered a proprietary daughterboard to adapt the new chip to the old footprint. Even if it were a direct swap of chips made by the same manufacturer the task of removing the old SMD and soldering in the new is difficult because of the tiny pins and confined space. btw, Quick Chip is a nice product for removing chips without damaging them. It will let you remove and replace opamps, which are only 8 pins and usually easier to swap out.

Find a junk PCB to practice soldering SMDs before you try it on your own equipment. Check the local recycling depot for electronic/computer junk waiting to be shredded.

If you are DIYing for fun, carry on, keep asking and learning and trying things. No matter what you break or screw up it is still fun to solder and scheme and dream. If something sounds good, you can celebrate until someone mentions a new part that is even better.     If you are doing it to save money getting better sound, that is a delusion. It will cost you a lot more money to R&D the mods yourself than it will a pro modder with a complete engineered package with happy existing customers. Another option is to just buy a good DAC and use the Oppo as a transport. There are a lot of nice <$1k DACs now.

[NordicNorm]

Thanks for the advice guys!

I'm under no illusion that I can compete with the pro-modders. I'm looking at this as a fun, learning hobby.

I used to be fairly electronics-savvy (i.e. Designing my own circuits using boolean logic and hand winding my own transformers).

So before I get too adventurous with the Oppo, I'll find a cheap experimental CD player as my first project.

Thanks for all the great "words of wisdom" guys!

Cheers,
Norm

[NordicNorm]

Well, I contacted Oppo, asked for a schematic and was turned down.

Apparently some of the circuit design is shared with other vendors!? Very interesting, indeed!

I would have thought, given how long it's been out of produciton, that sharing *anything* about the 980 would be OK!?

Guess I'll have to resort to the "hunt & peck" technique! 

[randytsuch]

Well, I contacted Oppo, asked for a schematic and was turned down.

Apparently some of the circuit design is shared with other vendors!? Very interesting, indeed!

I would have thought, given how long it's been out of produciton, that sharing *anything* about the 980 would be OK!?

Guess I'll have to resort to the "hunt & peck" technique! 

When I was modding CDP's, I would try to get the service manual for it.
All the information you need should be there, and you might have better luck getting it.

Randy