19-02-2014, 09:24 AM
(This post was last modified: 19-02-2014, 09:50 AM by Old Sparky.)
As a follow-up to my earlier post, I still have the speed change fault. If I play an LP the speed is correct at 33.333RPM. Switcing to 45RPM, a 7" disc is then played at the correct speed, but if I then switch back to 33.333RPM, the 12" LP then plays at 45! Switching the unit off, either at the wall or via it's on/off button, theen back on again after maybe a minute, the LP then plays at the correct speed. Though I haven't confirmed this yet, I suspect that the cause may be in the 33/45 selector panel, since the c/o switch operated by the cam gear is working OK. A further problem with the PU arm not lifting clear of the record at switch off was due to the pin of the lifter sticking in it's bearing, cured by the application of a small amount of sewing machine oil to the brass pin/bearing assembly, with the record deck inverted so that the oil ran down into the bearing. I did it this way to avoid removing the PU arm. The cartridge, incidentally is wired to a mute switch under the deck with some very fine wires, which are not colour coded, and can break off the switch tags if strained!!
Edit; One disadvantage of these decks is that there is no manual play setting, and, AFAIK, the auto mechanism & circuitry treats every 12" record as a 33.333RPM LP, and every 7" disc as a 45rpm. There is no way to set the speed independantly of the diameter, other than under the fault conditon above!, and no way to play 10" discs of either speed. Why this is the case on a machine which cost, I believe, about £400 in the late 1970s I don't know, but then B&O were always different!
Edit; One disadvantage of these decks is that there is no manual play setting, and, AFAIK, the auto mechanism & circuitry treats every 12" record as a 33.333RPM LP, and every 7" disc as a 45rpm. There is no way to set the speed independantly of the diameter, other than under the fault conditon above!, and no way to play 10" discs of either speed. Why this is the case on a machine which cost, I believe, about £400 in the late 1970s I don't know, but then B&O were always different!
