Looking for a picture of the Dolby CP650 Cat. 773 card

[David Ferguson]

This is a bit of an unusual request, but I'm looking for a high quality picture of a Dolby Cat. 773 card, as used in the CP650 processor to provide Dolby Digital decoding abilities. I'm trying to identify the chip and part numbers on it, but the only pictures I've found online - such as this one for an ebay auction - don't show it in quite enough detail.

Anyone have a Cat. 773 card lying around they could take a good picture of for me? If you were also be able to temporarily peel off any stickers on chips so I can see the part number underneath that would be fantastic too!

[Kyle Mikolajczyk]

This is the best I can do (from a few months ago, don't have easy access now) and its a 773Z rev. Scratch that, this is very compressed. Here is a better photo link: https://imgur.com/a/YnMt1KnIMG_0065.jpg

[David Ferguson]

Thanks Kyle, that's really really helpful! With both the ebay image I had, and your image, I can now see all but one of the chip numbers - just that one in the bottom left to identify!

Anyone have a picture of the bottom left chip, or could pull the board and get a picture/tell me the chip code?

Also, what's the difference between the 773 and the 733Z?

[Carsten Kurz]

I think I can see a Motorola 56K DSP in the middle of that card. Quite sure this does the audio decoding.

[David Ferguson]

There are two 56Ks on the 773 - but I'm 90% sure they're not for the audio decoding. The DA20 has three 56Ks, and they are used for the finding of the sync patterns in the digitised images of the Dolby Digital blocks, and running it through the reed-solomon decoder. The DA20 then has a Zoran AC3 decoder chip that's used for the actual audio decoding. My guess is that on the 773, the audio decoding is done by the two (or maybe just one of?) the Altera MAX chips, which are CPLDs (programmable logic devices - similar to FPGAs).

However, I haven't yet been able to see the part number of the chip in the bottom left, so it could be that's an audio decoding chip or something like that. Anyone have a picture, or know what it is?

[Sam Chavez]

Hope this picture came through. As to the Z designation, it's lead free initiative.

thumbnail-1.jpeg

[David Ferguson]

Hope this picture came through. As to the Z designation, it's lead free initiative.

Alas, I cannot quite read the info on that. I can see it's an AHA chip, but not the model. If you have the board in front of you, would you be able to tell me what the code on it is?

And that's interesting about the Z prefix - I'm curious why was there a need to designate which boards are lead free?

[Sam Chavez]

Here's another shot. I can clearly read if I blow it up. Hopefully you can too. PM me if you need to and I'll send you a bigger file. As to Z designation, it's a long and boring topic as initiatives tend to be, but the sense of it is you are not allowed to co-mingle leaded and lead free components or assembly lines. Kind of like Kosher.

[Randy Stankey]

... I'm curious why was there a need to designate which boards are lead free?

...you are not allowed to co-mingle leaded and lead free components or assembly lines. Kind of like Kosher.

Mixing lead solder and lead-free is a BIG no-no!

Solder is an alloy of at least 60% tin plus other metals. The traditional recipe has always been 60/40, tin/lead.
(Actually, the ideal ratio is 63/37.)

The problem with tin is that it can exist in one of two oxidation states. Stannous tin at +4 oxidation state and Stannic at +2. In one state, tin is pretty stable but, in the other state, it gets brittle and can, literally, crumble into dust. This is often called "Tin Pest." Tin can also grow dendrites or "tin whiskers" like tiny hairs. As those whiskers grow, they can form shorts between conductors if they are close together. Another problem is that tin solder can easily dissolve gold. If you use pure tin to solder gold terminations, they will become brittle.

While it is technically possible to solder with pure tin, the problems with things like Tin Pest and dendrites make it unusable for long term usage. Adding lead to the mix stops or slows down the problems, making a usable alloy.

Then, along comes the RoHS protocol. (Reduction of Hazardous Substances) Now, we can't use lead, anymore. We have to phase it out and use something else. The common lead-free alloys contain tin, silver, copper and small percentages of bismuth or antimony. It's still not as good as old fashioned lead solder but... A RoHS is a RoHS...

The big problem comes when Pb-based solder gets mixed with Pb-free. It basically cancels out all the benefits of Ag/Cu in the solder, making it useless or even worse than pure Sn.

Let's say you have electronic components that were prepared with Pb-based tinning on the leads then you build a circuit with them using Pb-free. The solder joints might look okay upon inspection. The circuit will test OK at final inspection. But, a year later (or even less) the solder joints will become brittle, crumble and fall apart. If that circuit ended up being used on, for example, the flight control system on a 737-Max, jet airliner... Uh-hhh... Houston, we have a problem...

I've worked in a few places where electronic components are manufactured. All of them had Pb and No-Pb solder lines. People in every one of them were dogmatic about it. Whole workstations are designated as Pb or No-Pb and never the twain shall meet.

Lead worstations have light blue table mats on them. No-lead workstations have light green and have yellow tape lines on the floor around them.

You are never, never, never allowed to move parts, tools or supplies between blue and green workstations!

If a worker is caught moving things between green and blue stations, all the parts in both areas are scrapped, all tools and equipment have to be chemically cleaned before reuse or else they are tossed out then the worker gets written up.

According to ISO-9000 and other standards, the worker MUST be written up because of traceability rules. If there is a problem during manufacture, it has to be documented and the steps to correct it have to be written down. One of the things that has to be documented is whether the person responsible has been notified and given proper re-training in order to prevent further mishaps. I know because it happened to me... ONCE!

I was preparing to tin-dip some parts in a Pb-based hot pot. Before you start, you have to record a temperature reading for the molten solder in the pot. For that, you use an electronic thermometer probe.

I used a thermo-probe that was laying on the table next to me to take a temperature reading but I didn't notice that it had a ring of green tape around the handle... A Pb-free probe. About a minute later, the line lead came over to me and asked "Did you just use THIS probe in THAT solder pot?"

Luckily, I didn't have any parts on the table, yet. I was still in the process of prepping my work area. I hadn't officially signed in to the work order, yet. I avoided a write-up because I hadn't signed in but I still had to stand there and get my ass chewed by the shop supervisor.

The thermo-probe (part of an expensive, Fluke electronic thermometer) had to be thrown in the trash. The tin pot was taken out of commission, cleaned with acid and had to be re-seasoned before it could be used again. I was the one who had to strip the whole workstation, clean it and reset it for use, again.

That's why you see those markings your circuit board(s). They are meant to keep PB-based and Pb-free solders from getting mingled.

If I was you, I'd check all the sound processors that you've been working on, swapping cards, to be sure that no Pb-based boards have been mixed up in any unit that has Pb-free or vice versa. You don't even want the two to be mixed up in the same chassis, even if they are different circuit boards.

Yeah! As Sam says... It's like Kosher!

[Sam Chavez]

And now we know how to build a watch. LOL.

[Jim Cassedy]

I had to replace a flakey power switch on a CP-650 a couple of days ago.
When I had the chassis open, I noticed all the chips & boards were covered with about
a decade of dust, so I decided to pull all the cards so I could take them out in back of the
theater to clean them up with a brush & blower. I took some pix of the major chips on the
773 card. My camera is currently stuck in a 'low res' mode, but these pix aren't too bad.
650Chips4.jpg
650Chips1.jpg

650Chips2.jpg

650Chips3.jpgC

Jim