Hi, I have previously fixed my D3 by the usual maintenance, changing center gear, lubrication and new belt for counter. Mechanically it seemed fine I was however never happy about the sound quality. I wouldn’t say it sounds bad, more lo-fi, somewhat comparable to the original DD model in sound. I was expecting more, not Dc2 level but at least DD30 level. The head looks fine, I can add a picture if needed. I have tried to adjust the head but still not good. Any ideas what to look for? Head, capacitors? Or could it be related to my next issue? Next issue it that the rec/play switch on the PCB have gone bad, suddenly the playback got quiet and I realized it was recording instead. I checked the switch and it needed to be in the extreme position to the PB side to not go into recording mode which the mechanics will not do. I desoldered the switch, disassembled it and cleaned the contacts inside. It was ok for awhile but now again broken. Could this switch have affected sound Q? Now the options I see is to try to get a replacement switch which i think will be hard or hardwire it to PB mode. Have anyone else had this issue?
@mybox80 The pause switch is working fine. The PB/Rec switch has been cleaned properly before but didn't really help. I have temporary hardwired the switch now to be able to continue looking at the audio quality. After bridging the switch and adjusting azimuth it actually sounds quite nice now on lower levels of recordings. In louder passages in the music it distorts, could it be needed to adjust PB levels? The level of distortion is not depending on volume control. I also noted that the VU meter is indicating way too low compared to D6C for the same tape.
Note the WM-D3 is not the most highly regarded when it comes to sound quality. However in my opinion it's not that bad that you can't listen to it, but nor is it as the D6C or DC2. Given this, it's curious how that switch made an improvement, the only potential explanation I can come with is there is parasitic capacitance in the switch and you get more treble without it. However if that is the case, the problem should be a lot more obvious on recording, as parasitic capacitances on that switch will change the bias level by A LOT. I remember one which had this issue, but after thorough cleaning of both the switch and PCB, the parasitic capacitance disapperead. I was able to measure this capacitance with an LCR meter. As for the initial problem of no audio, that sounds more like a mechanical issue, as the lever is not bent in the right position, so switch is not fully engaged in one direction. About the distorsion, do you get that on both the line out and headphone out ? The VU-meter not accurate is a common problem and it can be solved by changing a resistor in the feedback network of the sample and hold circuit. I'll come back and update with the value you need. EDIT: In regard to playback levels, these should indeed be adjusted to the reference value of 340mV RMS on the LINE OUT (47k loaded) when playing a 200nWb/m Dolby level tape. However do note this adjustment only affects 2 things: 1. The Dolby decoding quality. If levels are lower than the spec, playing Dolby tapes will sound muffled. If levels are higher than the spec, Dolby tapes will sound bright. Usually the levels are lower than the spec, hence many people think Dolby NR is simply junk and don't use it. 2. If the levels are misaligned by a lot, it can cause audible imbalance between the 2 channels. Usually there is an imbalance, the right channel being lower than the left, but not always that high to be audible. EDIT2: You can find the VU-meter issue here: https://stereo2go.com/forums/threads/sony-wm-d3-restoration-tutorial.6884/page-2 (post #26) A small part of this problem can also be the Dolby levels being too low, so that needs to be checked. Don't recommend using anything but a Dolby level tape (not a DIN tape).
Many thanks @Valentin for your input, sorry for taking so long to respond. I will clean the board properly and see if that makes a difference. I tried the switch manually and it needed to be in extreme position to work properly so I don't think that is the case. I am however focusing on playback for now as I se no reason to mess with recording if I cannot get playback to work properly. Yes I will adjust the dolby levels and see if that helps, just adjusted this on my D6C and it made a big difference. I have a proper Dolby calibration tape. The player actually sounds quite good now on tapes recorded less hot, no or little distortion even if I raise the volume but on hotter tapes such as metal distortion is very noticeable independent on volume level. With Dolby calibration I think it will sound the way it should except for the distortion.
