#1 Roksan xerxes
Posted: Sun Mar 06, 2022 1:46 pm
I got a roksan xerxes in to look at. A very early one given the serial numbers, the deck is a mk1 1985 example. the psu is a very early xps2, it still has a switch on it rather than buttons to change speed, so presumably a replacement for a blown up original.
It has the classic xerxes issue of a sagged top plate, and the classic xerxes issue of a psu that is broken.
The motor gives a twitch when turned on, but doesnt spin, suggesting one phase is not working in the psu. This could be a number of things, from caps, to the output devices on each phase, to the oscillators. So a long fault finding job. Or a new power supply which is a few hundred quid.
The psu has practically no ventilation, there are 3 holes in the back and 3 in the baseplate. its a pair of anodized aluminium bent panels with a veneered mdf cover over the top. So is effectively insulated. By the mdf trim.
No wonder these psus blew up from heat, the output devices have crappy little heatsinks and there are a pair of 5w coffin resistors which also get very hot, and there is practically no way for the generated heat to get out. Silly design flaw.
The top plate sag can be dealt with in a number of ways, roksan had a bodge that shimmed the bearing up so the platter cleared the none sagged bit which is practically useless as the motor and bearing are no longer aligned properly because of the sag which isnt dealt with by shimming it up.
Second way is to put a plate underneath the gap and force it into line, not a great way as the plate will be pulled down under tension from the sagged section
Having had a think, a better way would probably be to use some clamps to force it straight, then drill 2 holes horizontally through the vertical side of the plate, and into the sagged section and insert a pair of rods so eveything is held in alignment
Then just make a new top plate using the original as a template if i can get the thing running.
I think the cutout is also abit misunderstood, people seem to think its there to decouple the arm and bearing from the motor but its not. Its there to break up resonance in the top plate, so bridging the cutout to cure the sag shouldnt cause issues with the resonance control its actually there for, especially if the rods are acetal or similar
I need the top plate to be flat so i can fault find the psu under load, if i cant put the platter on properly and have it run i cant test under load
Its also missing a foot.
Could do with a new belt
And the bearing oiling
Cosmetically its very clean, very black and very 1985, even the black lid is cosmetically very black and not scratched.
Given all the work it needs and the potential hours it will need putting into it to get it recommissioned, the owner was going to part it out and try to sell off the good bits, so instead ive bought it as is for not alot of money.
It has an rb300 on it with an ortofon mc1 turbo, the 300 has had an epoxy repair done at some point to repair a crack in the plastic outrigger. It is perfectly servicable but the repair is visible.
Im confident i can repair it, the psu isnt particularly complicated and if push comes to shove every single component can probably be replaced
I havent had a belt drive deck in years, it will be an interesting project
It has the classic xerxes issue of a sagged top plate, and the classic xerxes issue of a psu that is broken.
The motor gives a twitch when turned on, but doesnt spin, suggesting one phase is not working in the psu. This could be a number of things, from caps, to the output devices on each phase, to the oscillators. So a long fault finding job. Or a new power supply which is a few hundred quid.
The psu has practically no ventilation, there are 3 holes in the back and 3 in the baseplate. its a pair of anodized aluminium bent panels with a veneered mdf cover over the top. So is effectively insulated. By the mdf trim.
No wonder these psus blew up from heat, the output devices have crappy little heatsinks and there are a pair of 5w coffin resistors which also get very hot, and there is practically no way for the generated heat to get out. Silly design flaw.
The top plate sag can be dealt with in a number of ways, roksan had a bodge that shimmed the bearing up so the platter cleared the none sagged bit which is practically useless as the motor and bearing are no longer aligned properly because of the sag which isnt dealt with by shimming it up.
Second way is to put a plate underneath the gap and force it into line, not a great way as the plate will be pulled down under tension from the sagged section
Having had a think, a better way would probably be to use some clamps to force it straight, then drill 2 holes horizontally through the vertical side of the plate, and into the sagged section and insert a pair of rods so eveything is held in alignment
Then just make a new top plate using the original as a template if i can get the thing running.
I think the cutout is also abit misunderstood, people seem to think its there to decouple the arm and bearing from the motor but its not. Its there to break up resonance in the top plate, so bridging the cutout to cure the sag shouldnt cause issues with the resonance control its actually there for, especially if the rods are acetal or similar
I need the top plate to be flat so i can fault find the psu under load, if i cant put the platter on properly and have it run i cant test under load
Its also missing a foot.
Could do with a new belt
And the bearing oiling
Cosmetically its very clean, very black and very 1985, even the black lid is cosmetically very black and not scratched.
Given all the work it needs and the potential hours it will need putting into it to get it recommissioned, the owner was going to part it out and try to sell off the good bits, so instead ive bought it as is for not alot of money.
It has an rb300 on it with an ortofon mc1 turbo, the 300 has had an epoxy repair done at some point to repair a crack in the plastic outrigger. It is perfectly servicable but the repair is visible.
Im confident i can repair it, the psu isnt particularly complicated and if push comes to shove every single component can probably be replaced
I havent had a belt drive deck in years, it will be an interesting project