Sony WM-D6C and DD Series Walkmans - WARNING! Read this before plugging in any DC adaptor!

Yes @Emiel , see the photo of one I just disassembled. Something happened in the controller circuit and it directly supplied 3.7v. Then it didn't recharge anymore. I use 1.2v eneloop in practically everything, but some things don't work if it's not 1.5v, for example the stylophone, that's where the problem happened, but it's a more robust equipment and didn't suffer anything. I have no experience with IKEA, but being 1.2v they should work fine, the problem is the 1.5v with controller.

 

Nowadays 2500mAh AA cells are very common and these offer more than enough capacity for walkmans.
There are some walkmans (the DD range for example) where the thicker 2500mAh won't fit in the device, so 1300mAh ones will have to be used instead.
But even in such cases, the 1300mAh are enough for normal use. NiMH chemistry offers good autonomy, I see no point in using anything else.

@Romulo Lubachesky What happened is the switching transistor shorted and thus connected the battery directly to the output through the coil. See image attached.

 

Deb64 with more crucial advice. I found this thread last Summer. No AC adapters, even original one, on DC and DC6 is indeed sage advice.

Been a Sanyo (now Panasonic) Eneloops user since 2006. The originals I bought in 2006 are still working great for me. Stocked up last year on more packs of them to take me into the next few decades.

 

@Deb64 Sorry to resurrect this thread, but doe the TC-D5 line of devices share the same CX20084 motor and therefore the same issue here presented by the WM-D6C

 

What I would propose for the WM-D6C is to cut that trace which leads to the jumper wire that feeds the CX20084 just where it joins down from the external power jack and insert a reverse-polarity protection Schottky diode (1N5818) to that break---that way it protects BOTH the battery and external power supplies from reverse voltage. Then put a 4-volt regulator (Microchip Technology MCP1702-4002E/TO) in place of the jumper wire. That will protect the CX20084 from overvoltage.

 

Can you share some photo or diagram where to solder diode and regulator?

 

I don't have the ability to edit pdfs but here is a screenshot of the WM-D6C PCB

My suggestion is to put the MCP1702-4002E regulator in place of the jumper wire shown above between the red traces that feed the power pin (8) of the motor control IC 601; input is the upper trace and output is the lower trace; ground to the ground trace shown connected to the - side of C603. The Schottky protection diode 1N5818 should be placed in the path of the trace JUST ABOVE the connection to the jumper wire; this will require cutting the trace so the diode is in series with both the feed to the jumper/regulator and the feed to the right side of the board. That's the best I can describe it; close inspection of the schematic will shed further light. This mod is for experienced techs ONLY.

 

Hi @Deb64 ......are you doing servicing/repairs on Sony WM DD3's pretty please?

 

Hi @Buckie1967 . PM sent.