Post by redlion on Jun 9, 2020 3:10:10 GMT 12
Hi all, Boy am I glad to find this place, just been reading a most informative article by DarkLantern re his RP3 refurb (https://darklanternforowen.wordpress.com/2018/07/13/rega-planar-3-restoration/).
To rewind a bit, recently rediscovered my old RP3 which has been boxed up for the best part of 25 years, finally got it set up after discovering that modern amps no longer have phono stages (wtf) only to discover that it will play the first track or two of a record pretty well before slowing down - considerably. So I have cleaned and re oiled the sub platter bearing which failed to solve the issue, and now have checked out the PCB that supplies the motor. The capacitor is cracked pretty much like the one shown in DL's write up so am planning to replace that along with a new resistor, although that looks to be OK.The resistor I have is a 15kOhm I should say that the deck is a circa 1987 vintage, bought new and judging by SN is a little older than DL's.I have checked the voltages on the motor coils and they seem to be way low and unbalanced with readings of coil A (red) 59V, coil B (blue) 70.2V and across AB is 66.7V. My understanding is that A and B should be between 90-110V and near enough balanced, not sure what AB should be. There is also the issue of phases which has gone right over my head. The existing capacitor is a 0.22uF which I understand to be pretty standard. The resistor gets pretty hot (about 60c I would judge, but dont know if this is OK or not. Fact is if I had not tripped across DL's write up I would have just replaced the resistor and cap like for like and lived the rest of my life in blissful ignorance but now I am concerned that some adjustment may be needed to the component values to bring the motor voltages to where they should be as DL did but I have not got a clue how to calculate new values. My question to anyone here with the knowledge is what if anything should I be doing apart from replacing the two components. DL adjusted the value of the capacitor and there seems to be a large variation in the resistor values that are used, anything from 6.8k to 15k. One more thing, there is talk of using trimmers on the A and B feeds but I cannot find any reference to specific values that would be required.Hoping that there is someone on here who can help me with this. Cheers.
To rewind a bit, recently rediscovered my old RP3 which has been boxed up for the best part of 25 years, finally got it set up after discovering that modern amps no longer have phono stages (wtf) only to discover that it will play the first track or two of a record pretty well before slowing down - considerably. So I have cleaned and re oiled the sub platter bearing which failed to solve the issue, and now have checked out the PCB that supplies the motor. The capacitor is cracked pretty much like the one shown in DL's write up so am planning to replace that along with a new resistor, although that looks to be OK.The resistor I have is a 15kOhm I should say that the deck is a circa 1987 vintage, bought new and judging by SN is a little older than DL's.I have checked the voltages on the motor coils and they seem to be way low and unbalanced with readings of coil A (red) 59V, coil B (blue) 70.2V and across AB is 66.7V. My understanding is that A and B should be between 90-110V and near enough balanced, not sure what AB should be. There is also the issue of phases which has gone right over my head. The existing capacitor is a 0.22uF which I understand to be pretty standard. The resistor gets pretty hot (about 60c I would judge, but dont know if this is OK or not. Fact is if I had not tripped across DL's write up I would have just replaced the resistor and cap like for like and lived the rest of my life in blissful ignorance but now I am concerned that some adjustment may be needed to the component values to bring the motor voltages to where they should be as DL did but I have not got a clue how to calculate new values. My question to anyone here with the knowledge is what if anything should I be doing apart from replacing the two components. DL adjusted the value of the capacitor and there seems to be a large variation in the resistor values that are used, anything from 6.8k to 15k. One more thing, there is talk of using trimmers on the A and B feeds but I cannot find any reference to specific values that would be required.Hoping that there is someone on here who can help me with this. Cheers.
