Hi Forum, __edited__ I am a newbie but ventured into the restauration of a DD2. I bought the device lately -and found the operation was ok but with the obvious center gear crack clicks audible. So I went into repairing it (using the kit and the step-by-step instructions of Marian Mihok - thanks!!). That part went well, center gear is now back in shape. But... firstly [problem#1] I broke the tiny plastic notches from the plastic slider that (I think) moves the tape head towards the tape. So I need help here - any experience about how to fix this (see enclosed pictures)? And secondly [problem#2] I have an issue with the Play function. It seems to operate normally, but the tape speed is too high. It is not as fast as fast forward, but I would guess something like twice the normal speed. Not sure where that comes from. Could it be just an adjustment issue - I also changed the capstan ring? Any help with problem #1 or #2 is highly appreciated! Best, Klaus
First, in regard to the plastic slider: it's unlikely you can repair that one, I suggest posting in the "Gear that you want" section and ask for a slider. Those broken pins also have the purpose of keeping the slider flush with the chassis, so even if you glue. Problem 2 can be caused by 2 things: a burnt CX20084 servo IC from powering the unit with reverse polarity or a missing FG signal. Check the FG coil resistance at the PCB (black wires), it should be a few hundred ohms. It could also be an adjustment issue, but only if the trimpot is turned all the way or close to it. Replacing the capstan ring and servicing the unit should not change the tape speed, as the motor has a fixed position. The thicker capstan ring will change the motor position slightly, but that can only cause a very minor speed difference, like less than 10Hz.
Thanks a ton for your reply Valentin! I put out a post in the "Gear that you want" section - didn't see it before. As per speed issue I hope I did not burn the IC, I am running on battery only and am not aware of missfitting the batteries. Nor have I adjusted the speed (not even sure where the potentiometer is located). FG I googled is the frequency generator. Located at the capstan I read somewhere. That I removed so maybe the fault comes from there, will check with the resistance (Ohm-Meter between the two black wires, right?). Meanwhile I also noted that FF and REW only works if there is no tape inserted. When the tape is in it seems to block the rotation. So I am facing even more issues. Not sure what to do, so I will disasemble again just in case I made a mistake somewhere. Maybe the faults then disappear as magically as they occured...
If the walkman had correct tape speed before the repair and you only used it on batteries, I would exclude a burnt servo. Most likely one of the FG wires got detached either from the PCB or from the coil and the servo has no FG signal. Measure in ohm mode between the 2 black wires. If you disassemble the unit again, I recommend doing these 2 steps as well: https://stereo2go.com/forums/threads/wm-dd-series-new-center-gear-wobble-problem-and-solution.7387/ https://stereo2go.com/forums/threads/sony-dd-series-play-ff-rew-buttons-not-latching.7524/
Again thanks Valentin! Indeed I noticed the center gear wobble - one more reason to disassemble again. Need to squeeze out some time to do and will revert back with my findings!!
I have a measurement now for the FG, measured between the 2 black wires leading to the Capstan: 0.5 Ohm, meaning no resistance. Far away from the few hundred Ohms that it should be. However I cannot detect anything wrong with the capstan, other than having removed it and put on a new capstan belt. The black cables are not lose. I guess I am stuck here... However I have an idea how to fix the broken tips of the plastic slider. But need a very small drill first.
I made a measurement on a DD2 unit, the FG coil measures 702 ohms in circuit. You clearly have a problem, maybe the wires isolation has been damaged and they're touching together or the metal chassis. 0.5 ohms indicates a short. Are you sure you are reading 0.5 ohms and not 0.5 kilo ohms, which would mean 500 ohms ?
I have a digital meter, Ohm ranges are 2M, 200k, 20k, 2k, 200 (no k). I set it to 200 and the reading was 0.5 (practically the same as if I am directly connecting the tips of the meter - no resistance). I checked the cables and they are fine. Nothing lose, nothing damaged. It is strange, as said the speed was ok before disassembling and at the same time I am not aware of having put stress on the capstan or the wiring. Anyway the conclusion seems to be that for whatever reason the FG went bust. Nothing to repair here that I could see. I guess I need to get a donor device and hope I can retrieve the capstan/FG from it...
I would do another check before drawing that conclusion: desolder one of the wires and measure out of circuit. Make sure the short does not come from the PCB...
