Hello guys, I need for my DD2 the cap values and the positions where each cap belongs. Before someone suggests just to open the unit und look what caps I need, this is the problem there are new caps in but I think with the wrong values. I let someone recap the unit because my soldering iron is trash and I think he might didn't read the values properly. So I would much appriciate if could give me the values or the service manual (as PDF). Thanks in advance Christopher
Hello Chistopher, Have you solved the problem with the capacitors ? What makes you believe they are the wrong values ? What is exactly wrong with the unit ?
Hello, yes I have finally repaired this unit. Now it works perfectly. The values were right and so the board itself was the problem. I bought another DD2 for parts, this one actually has a non broken center gear. Now it works all fine, but troubleshooting was a real pain. The main problem was a really loud hum sound while playback. Later I found out that the ground connection cable from the head to the board was broken. I resoldered the cable together again and it works. But an intersting thing I found out was that swapping the boards did not work because tten there was no sound at all. So I swapped the heads too and the sound was back. But both heads work fine, and I found out both boards look different, thats a bit odd in my opinion because the are the same walkman models. Maybe you or someone else know why it's like that.
I'm glad you repaired the unit ! It is possible that the WM-DD2 was made in 2 generations, so they made improvements in the latest one. Thay may be the explanation to why the boards are different. Please post some pictures of the boards. I would like to see what the exact differences are. I may be able to give a more exact explanation of why they are different. Do the 2 heads have identical part numbers ? Did you measure their coil resistances/inductances to see if they're the same ? I would like to know more about the problem and how you solved it as it seems very strange.
You're right the heads have different part numbers. I did not measure their resistance or inductances because I don't have a good multi meter. Sorry for the pictures of one of the boards but I don't want open the machine again and desolder everything so there aren't pictures of the whole board but some things are different for example the positions of the dolby level potentiometer.
From what I have seen on SONY walkmans and portable recorders, I would assume the head with a sticker on it is an older version (PP227-306F). But I think they might be interchanghable. Regarding the 2 PCBs, I can't spot any major difference; they use the same chips and similar layout. Only the position of some components seems different as you mentioned, maybe updated versions of some chips. Just from looking at the pictures I would also assume that functionally, they are the same. How did you manage to solve the problem ? And what was the problem exactly ? I didn't quite understood...
So as I swapped the PCBs (only PCB not the heads) there wasn't any sound. I checked ervery soldering connections and they seemed fine, then I swapped the heads too, because I knew that the other walkman had sound. After changing them the sound came back, so it seems the heads aren't interchangeable as of my experience. Basically in short I took the PCB and head from one Walkman into the other Walkman and that solved my problem.
Does the other PCB work with its own head ? The head preamplifier is the same on both boards, BA3304F. It's a chip used in many walkmans and certainly does not have special requirements for a very particular head.
