My dd9 has been taken apart by 2 so called Walkman specialists over the past 10years to try and fix it and while doing do making things worse. Bring on @Deb64 who offered to look at it and after her very thorough and details assessment she went on a mission to find someone to 3d print a new gear that was missing teeth as well as replacing door hinge, belts and pinch rollers etc. Today i got it back and all is working again after so many years sitting in its original box. I can not recommend Deb64 more, and now will certainly be booking my 701c in to get that back working. …and on that, if anyone knows where i can get aa replacement gum battery cover for the 701c please let me know ; )
Thank you for your kind words. This was a rather challenging repair but I was lucky to be in the right place at the right time. The previous specialist to check it had correctly diagnosed the faulty gear wheel so I started to look into whether I could get a replacement 3D printed. In the meantime, somebody on here had found a replacement available in China on the Goofish site. I managed to order a couple of gear wheels via Superbuy. I bought a replacement door hinge part from a seller on Ebay. With the new parts, as well as rubber parts from www.fixyouraudio.com, and a good clean, it all came together nicely. Replacement gumstick batteries here: https://www.ebay.co.uk/itm/371451382056
id highly recommend these usb-c gumsticks for convenience sake- (they are all pretty much identical in design) https://www.ebay.com/itm/286217995197 sounds like progress in part availability from 3D printing is what really saved your dd9- still good work though deb
I don't think the gear wheels are 3D printed after all. But it is good news that somebody is making replacements for this part. I would be very wary about using the gumsticks recommended by @Squiggly as they use lithium ion cells which operate at 3.7V and use an internal regulator to reduce the output voltage to 1.5V. They are fine so long as the internal regulator is working but if it fails you don't want to be putting 3.7V into your 40 year old walkman which is full of irreplacable ICs and transistors.
uh you kinda present that as if its an eventuality/fact when estimated failure rates are so rare youd have better or equal chances at winning the lottery chance of failure already crazy unlikely, and it failing in such a way it still can output voltage to fry anything outside of the battery circuitry itself (while the battery still is able to somehow hold a charge) is so unbelievably unlikely i havent even heard of that happening with any modern batteries tbh if they do fail itll most likely only kill the battery itself, its good to be cautious but thats just being a bit paranoid lol
This is not correct. If the internal regulator fails, the battery can deliver 3.7V instead of the required 1.5V and it won't necessarily destroy the battery. I had a WM-DD33 in for repair recently which may have been damaged by a Lithium ion AA cell delivering a high voltage. The DD-33 was running slowly and had bad wow and flutter. I found that the fault was due to IC602 (MSM5841MSK, PLL chip) having failed. Fortunately I had a spare chip. Once I had replaced the faulty chip it ran at the correct speed and with good W&F. It is very unusual for a MSM5841 to fail. I have worked on well over a hundred walkmans now and I have never seen one of these chips fail. The WM-DD33 runs from two AA cells, giving a B+ of 3V. It has an internal DC-DC converter which steps up the 3v to 8V. The 8V rail powers the MSM5841 via a 3.3k resister, delivering 6.2V to pin 4. I was rather puzzled as to what could have caused the original chip to fail. All the voltages looked OK on the bench. The customer had only powered the walkman with batteries. I remembered hearing somewhere about li-ion AA cells with internal regulators and that they could fail so I asked the customer if he had been using them. Sure enough, he had. I don't know for certain if the Li-ion batteries caused the failure. The customer didn't have any way of measuring the voltage and I certainly wasn't going to ask him to send lithium ion batteries through the post, especially ones which may be faulty. Therefore I'm not 100% sure that the batteries caused the failure but I consider them to be the main suspect.
