Sony DD portables genealogy

No, I was reffering to the 3 versions of the heads: pointy, 35711 and 35712 permalloy. Will edit the wording for more clarity.

 

Does anyone know the WM-D6C serial numbers affected by the Dolby circuit changes specified in Supplement 1 (January 1985)?

 

Good findings, but are they conclusive to make updates to the table? Let me know, happy to improve the overview!

 

Here's what I have gathered so far on the Sony Walkman D6C history (updated 8/30/2024). This is from postings on stereo2go, tapeheads, and for sale listings on eBay:

• February 1984: Sony Walkman WM-D6C released. Amorphous "pointy" PA259-3602A head marked "Japan". Brown/green phenolic PC boards 1-611-494-11 with through-hole components.
  
• January 1985: Supplement 1 notes Dolby chip change from CX20068 to CX 20218, as well as surrounding component value changes. PCB now -12. Serial #s affected are unknown
  
• Change from pointy head to rounded amorphous head 35711 between serial # 71236 and # 72264. Date unknown
  
• 1988: Change to Dolby sticker color from white (silver) to black between serial # 114373 and # 117947
  
• March 1994: Supplement 2 (serial # 267201) notes change to green glass epoxy PCB 1-651-545-12 with SMD components.
  
• April 1996: Service Bulletin 395 issued. The motor was changed from X-3305-830-1 to X-3370-805-1.
  
• April 1999: Supplement 3 shows two resistor values were changed in the French model.
  
• June 2001: Supplement 4 shows main PCB changed to 1-651-545-14; motor drive servo circuit redesigned with servo IC now CX069A. Service manual was issued as Rev. 1.1.
  
• Change to permalloy head 35712 in serial #s ~50xxxx and above. Marking "amorphous head" on the case is no longer present.
  
• 2002: WM-D6C production discontinued

Please update the genealogy table. If anyone has additional information, PLEASE POST IT.

 

The first update of 2025!
We now have 645 models on the site that are publicly available!
The PDF overview of the first post, was made interactive and now links to models that are on the site.
See for yourself by following the link to the news article: https://walkman.land/news/sony-disc-drive-overview-available

 

Great work!