Hi , how do ? Any chance can someone help me with set up a right speed tape in my walkman D6C , please ? Serial number 235957 . I've done this few times with dd series , but unfortunately I can't find this bridge which I have to unsolder in D6C , in the service manual there is a picture but not in good quality and I think my one is deferent. This bridge is called Q307 ? Thanks very much
I have marked up your photograph with the position of the bridge here. When you desolder the bridge, you need to clean any solder flux from the gap otherwise it will act as a capacitor and still pass AC and behave as if the bridge was still soldered. I had this happen on one of the later surface mount type D6Cs. The photograph in the service manual is marked up incorrectly.
Thanks very much , u r a legend . I open the bridge and adjust 3090Hz then I trying to close the bridge and I still have 2970Hz and if I try to adjust the Rv601 jumps to 3250Hz , I can adjust 3000Hz with open brigde and not soldering it , is that okey ? Thanks
There may not be a lot you can do to adjust the speed. If you run the walkman with the solder bridge open, then the motor speed is not locked to the quartz crystal speed and is only being controlled by resistors. It may drift and is unlikely to be very stable. The adjustment you are making when adjusting RV601 is more of a stability adjustment rather than a speed adjustment as the speed is determined by the frequency of the crystal and the circumference of the capstan. If you are using a 3kHz alignment tape then the speed you have (2970Hz) is within a 1% tolerance which many people would be happy with. Personally, I could live with it. You could try replacing C605 which is the orange 3.3nF capacitor, which is behind R603. These orange capacitors have been discussed a lot on Nakamichi forums as they tend to fail after about 30 years. I have recently replaced the equivalent capacitor on a couple of WM-D6s, which is 6.8nF, as they have started to cause problems. I have found that by selecting the value of the capacitor it is possible to change the speed at which the motor runs, when the speed tune function is switched off. I have not tried this on a D6C but you may want to experiment with changing C605. You don't want to change the value very much. Just get a bag of 3n3 capacitors (mylar or polyester film type) with 5% or 10% tolerence. Measure them with a capacitance meter first and note their values, then try them in the walkman. I found with the D6 that the higher the value of the capacitor then the slower the motor will run.
Thanks very much for reply. I will do that , I just open d6c today again , and trying to setup motor speed , even when I turn up to 3450 , then close the bridge by inserting a screwdriver , motor speed still going down to 2970 no matter what I do . Strange ,
