I've been trying to improve wow & flutter of my WM-D6. On a certain recording (that I use WM-D6 to record then play) I find pronounced vibration detected at a specific section that its the frequency. Very clean otherwise. I've resolved it mostly and these I believe contributed positively - replacing capacitors around control system - shielded cable connecting RV601 and S601 has grounding to chassis, and it's quite important to keep it grounded - motor itself can cause the trouble (esp around 1.5 khz resonance) - I opened up the cap on the rear side of the motor and used slight amount of deoxit - replaced Q603 transitor (I think I might have damaged it while soldering back the capacitor on CP602 pin 1 by shorting it to the transistor collector). Now it is really solid but my picky ears might detect some other weird frequency ...
Think it would be useful to post a W&F figure measured with WFGUI, so we can see the actual figure you obtained. Also, you didn't mention anything about the rubber, which in my opinion should be replaced. Given this, I want to add a couple of remarks: - while typically an old capstan rubber ring won't increase the W&F, seen situations where a very old rubber made the motor spindle slip on it from decreased grip. - an old rubber ring will wear the motor spindle unevenly, so another reason to replace it. - if motor spindle has uneven wear, sanding it can also improve the W&F figure. - motor position relative to the flywheel also matters, it needs to be perfectly perpendicular when running.
Thank you @Valentin for the reply. I will try WFGUI but will need to revive one of my dead Windows laptops first -- my journey of correcting W&F could have been much smoother. - I forgot to mention I replaced the capstan wheel tire. It was sourced from an Ukrainian eBay seller. At first it worse when I first installed it and realized it needs to by applied really really flat by pressing the corners delicately. Then it made it all smooth. - I have two more WM D6 units with much lower usage (bought from eBay and fixed) and they don't exhibit any W&F issue from my simple record & play tests. I've been swapping spindle with them and I found W&F only from my original unit. (I am too emotionally attached to that unit for sentimental reasons). This way I was able to collect the data that the motor indeed had issues, but no spindle issue. - Motor position is indeed a great point. I will try to align it again More tests to come now I learned WFGUI can help -- Thank you!
Some test from WFGUI -- I didn't have 3khz test tape. So I recorded using WM-D6, then replayed with it. So, the measure might read like 1.4 x of the actual value. I consistently observe 0.04~0.05 WRMS. Picture was one of the best number I read from the screen. IMG_1291 by Chang Song posted Jun 14, 2024 at 6:40 PM
