Willster, this is from Arthur Salvatore's site, maybe you can get some ideas from it:
GOLDMUND STUDIO MOTOR REPLACEMENTS
Below is potentially "Great News" for the owners of the Goldmund Studio turntables. It is from a veteran reader and contributor to this site; Here it is, slightly edited;
"...I found out that an EDS-900 Dual 704 motor is nearly identical to the one used in early Goldmunds. Furthermore, the EDS-1000, used in the Dual 701/721, is an IMPROVED vesrsion. I recently aquired three junky Duals and will check these motors out. If this, indeed, is true, than older Goldmunds can be kept going indefinitely. Dual Europe has both new EDS-900 ($300) and the EDS-1000 ($650) in stock, but they can be salvaged form old tables for next to nothing (I paid $140 for three). Will keep you posted as to feasabilty of retrofitting. You can let all stranded Goldmund owners get in touch with me for any questions they have. Goldmund Europe still has miniature motors for the arm in stock ($300 a pop)."
This update from the same reader arrived a few days later;
"Dual motor update: Dual 701/721 motors are larger in diameter, so some machining is required. Other than that, they could be used. Of course a HANDY guy can do it. Dual power supply must be used. Not a DIRECT replacement, no. Dual 704 looks to be much closer from a picture, but I won't know till I get it (next week)."
Futher Correspondence- These updates are from the same helpful reader above. After a little editing;
"Final breakdown on the replacement motors from Dual tables:
Dual 701/721, EDS 1000/EDS 1000-II- These motors are 5.5" in diameter, while the original Goldmund Papst is 4 3/8", so machining is required.
Dual 704 (may be also 504, never got that, EDS 500 motor), EDS 900 motor- IDENTICAL top, diameter, color etc. Major difference: circuit board extension beyond housing about 0.5" x 1.5", so some machining is required. This motor is not as thick as the original, has less of a magnet and as a result, less torque. Dual's own platter is much lighter.
EDS 1000 has more torque and it is smoother than original Goldmund. There is a posting on Audio Asylum by a Goldmund Studietto owner who actually wanted to replace a WORKING Papst with an EDS 1000 to acheive smoother ride.
Further, both motors are fed via their own electronics, and MUST be used with it. It is not bulky, will fit inside. All in all, I would only recommend these if all other options are exausted (that is, the original motor replacement at about $500, if you can find one). I paid $50 for a Dual 704, so it is a cheap fix, but Goldmund platter probably will have to be given a spin to start turning!
The last word- The Dual 704 (EDS 900) motor definitely wouldn't work - not enough torque. So forget about quick cheap fixes."
Personal Note- This reader deserves thanks for sharing his time, investment and efforts. After everything is said and one, the EDS 1000 motors, found in the Dual 701/721, can still work, though "some machining is required". They may even provide an improvement!
GOLDMUND STUDIO MOTOR REPLACEMENTS
Below is potentially "Great News" for the owners of the Goldmund Studio turntables. It is from a veteran reader and contributor to this site; Here it is, slightly edited;
"...I found out that an EDS-900 Dual 704 motor is nearly identical to the one used in early Goldmunds. Furthermore, the EDS-1000, used in the Dual 701/721, is an IMPROVED vesrsion. I recently aquired three junky Duals and will check these motors out. If this, indeed, is true, than older Goldmunds can be kept going indefinitely. Dual Europe has both new EDS-900 ($300) and the EDS-1000 ($650) in stock, but they can be salvaged form old tables for next to nothing (I paid $140 for three). Will keep you posted as to feasabilty of retrofitting. You can let all stranded Goldmund owners get in touch with me for any questions they have. Goldmund Europe still has miniature motors for the arm in stock ($300 a pop)."
This update from the same reader arrived a few days later;
"Dual motor update: Dual 701/721 motors are larger in diameter, so some machining is required. Other than that, they could be used. Of course a HANDY guy can do it. Dual power supply must be used. Not a DIRECT replacement, no. Dual 704 looks to be much closer from a picture, but I won't know till I get it (next week)."
Futher Correspondence- These updates are from the same helpful reader above. After a little editing;
"Final breakdown on the replacement motors from Dual tables:
Dual 701/721, EDS 1000/EDS 1000-II- These motors are 5.5" in diameter, while the original Goldmund Papst is 4 3/8", so machining is required.
Dual 704 (may be also 504, never got that, EDS 500 motor), EDS 900 motor- IDENTICAL top, diameter, color etc. Major difference: circuit board extension beyond housing about 0.5" x 1.5", so some machining is required. This motor is not as thick as the original, has less of a magnet and as a result, less torque. Dual's own platter is much lighter.
EDS 1000 has more torque and it is smoother than original Goldmund. There is a posting on Audio Asylum by a Goldmund Studietto owner who actually wanted to replace a WORKING Papst with an EDS 1000 to acheive smoother ride.
Further, both motors are fed via their own electronics, and MUST be used with it. It is not bulky, will fit inside. All in all, I would only recommend these if all other options are exausted (that is, the original motor replacement at about $500, if you can find one). I paid $50 for a Dual 704, so it is a cheap fix, but Goldmund platter probably will have to be given a spin to start turning!
The last word- The Dual 704 (EDS 900) motor definitely wouldn't work - not enough torque. So forget about quick cheap fixes."
Personal Note- This reader deserves thanks for sharing his time, investment and efforts. After everything is said and one, the EDS 1000 motors, found in the Dual 701/721, can still work, though "some machining is required". They may even provide an improvement!