Chasing the Sony CX20084 speed chip for D6C walkman

if we were to commit to reverse engineering the CX20084 we might be able to but the project into the efabless shuttle program which is sponsored by google so there would be no chip manufacture costs however there seem to be some pretty stringent requirements to qualify and i doubt a 20+ year old chip would meet those needs

 

Regarding the chips from China, are they all crap or did someone manage to find one working?
Considering all of what we've just discussed, I tend to think they're all crap...

 

Im sure some chips are good but its getting a reliable supply of them and being able to be sure they're good and have no defects.
I dont think anyone would complain about a slightly weaker chip that wont last as many cycles but equally you could get a batch of chips which are trash and can potentially cause damage to other components once installed

 

Question is "do we have someone who knows to design layout in silicon ?" @nickkov Are you into that or do you know someone else who can do it ?

As for the efabless shuttle program, I looked into it. To me it seems they are interested in state of the art digital chips.
I almost bet their biggest interest is into AI stuff, because Google is essentially an AI company.
They want open source designs because they can use them as building blocks in their future products, so this way they get the R&D done at a lower cost.

@root32 In regard to the chips from China, there was another thread where a member did a jig for testing CX20084s. According to him there is a version that actually works, but is very easy to fry.
I can't say as I avoided those Chinese ones because I can't afford doing an unreliable repair for someone in another country and make that person pay 4 x shipping cost in case the device stops working after some time.
In my personal collection I have only one D6C, which was bought in working condition. But even if I were to do such a repair for myself, I would still only use a genuine chip.

@nickkov As for the weaker chips, it depends for what you use them. If you do the repair for yourself, you can always re-do it later on, but if you do it for someone else you can't afford that.
The risk of damagining something else is rather small (never heard of such situation), but there is added time, effort, etc. to re-order another chip, desolder again, do the servo adjustments again, etc.

 

I was looking into silicon wafer design however i doubt id be proficient enough to design a brand new chip possibly copy transistor layouts into a functioning circuit but without knowing exactly what the chip is doing as far as internal logic is concerned and what style of printed transistor it uses it's all a bit pointless. As far as my use case for the chips i was looking into using them for personal projects so i can settle with lower grade chips but i understand someone like yourself cannot.

 

Some are good, particularly if they were ordered before 2017, I have about 5 left that I ordered in 2018 which work ok, but there are ALOT of fakes now, I would ignore anyone offering them very cheaply in large quantities, especially if they have "Sony" printed on them- I haven't yet seen a fake CX20084 with no Sony branding...

 

I bought mine ages ago. I can't check exactly when as eBay purchases history doesn't go back before 2019 so possibly I bought them in 2018 or earlier. They are probably fakes but at the time I purchased them there were plenty of sources listed on eBay. Not so any longer of course.
I had a contact at Jotrin Electronics who searched for me as they had one CX20084 listed as "in stock" on their online site. It was $90USD and I jumped at it...but of course it was no longer in stock and their inventory had not been updated after that single remaining IC was sold. Since then no luck from the contact who has put out a "wanted to buy" on my behalf.
Sadly your only option is source one from a scrapped DDII through to a DD30. Of course that's not going to be a simple task nor cheap.

 

The best option for me has been to chase for broken DD11 units in bad physical shape. I gave up on buying chips after receiving fake ones twice in a row.

Please note that the first gen DD models, DD and F5 don’t have this chip.

 

Those without the SONY branding are most likely genuine chips. Never seen a fake one myself without a SONY logo.
The older ones (late 80s) are like that, while the newer ones used in the newer versions of D6Cs have the SONY branding and a different format of date code on them (if it is a date code at all). I'm talking about the genuine ones here.

I bought genuine CX20084 ICs well after 2017 (the ones without SONY logo) and to me it seems the price is the main factor determining if the chip is genuine or not, second to the seller.
Serious sellers who have this IC don't have many of them in stock and never sell in bulk. So if a seller sells packs of 2-3pcs or has 100pcs in stock, that's a guaranteed fake.
Genuine ones cost at least 50$/euros without any shipping or VAT. And as of 2023, they're pretty rare to find and indeed finding a donor unit might be easier than to find a genuine IC.

 

I am working on a solution to this currently...

 

Have done with ba6301 ic. With same Wow&flutter.

 

Well done
The ba6301 is designed to do the same job in a VCR
https://datasheetspdf.com/pdf-file/233655/Rohm/BA6301/1
How is power consumption?

 

We good. playback mode 5v 0.05-0.07a

 

Hello,
I ask you if you managed to make a circuit small enough to let it go inside .... what I see in the picture I think is a prototype I would say quite voluminous

 

Absolute possible. very few components, with SMD resistor

 

Just because it is a topic that interests many
The block diagram you see in the photo of @Hn14197 comes from a Technics sl-bd22 turntable ..for those interested

 

I wouldn't be surprised if it was the same thing tailored to Sony's requirements.
Rohm developed many, many ICs for Sony...

Ford were great at doing this in their engine management systems, taking jellybean components and attaching their own codes to them so you cant easily replace them when they go bad.

Do you run this on the 12V system or the 4.5V system?
How does it perform below 4.5V?
Are these easily obtainable?

 

Thanks for your question. We can use 78l05.
Finaly, wow flut is pefect!

 

Wow, awesome! Any noticeable difference after doing this? Did you have to trim the case to fit the circuit?
Would you mind sharing the part list? I'd love to try building it myself.

 

These are just some random musings of mine:

Another few options / possibilities is for someone who is fluent in the language and residing in China... (who is perhaps an avid collector of such Sony stuff like member Kent) to somehow try and contact the maker of these fake chips. To somehow persuade them to make better ones that last? Or collaborate with someone to make ones that work better than these fakes ones that... seem to quickly fail. It seems these fakes sometimes do work, briefly, right?

Maybe they are a failed attempt at a real product that could be tweaked... but the money isn't there yet to make that happen.

Someone is making these fake chips. Can't whoever they are... just make them to work better? Or can't they? Or don't they care either way? The talent and capability to make chips that work reliably... exists. If they made good reliable chips they could make more money than they do now with the fake ones, right? Maybe the time is not yet right and in a few more years they may have the incentive?