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Northstar

pdevine said:
Thank you!
Click to expand...
Apologies, my GW has gone missing. I have another on order but there will be a delay :(


In other news
The original Tandon TM100-2A has been unreliable since being installed. Sometimes works fine, then refuses.

When I finally managed to find a filament lamp, the speed was off, however while I could adjust it, it would keep jumping to different speeds. Its possibly the speed controller, but first the motor and the spindle feel to be in poor condition. Stripped down the motor and while the brushes are absolutely fine, the internals are filthy. Both gimbal bearings are mucky so a quick clean and now everything spins nicely. One bit of advice, if you ever open one of these, watch out for the brushes and the springs. Pull the pully off first, then the top, then push the rotor out while keeping the bottom on the spindle, you can then carefully remove the rotor and catch the ejected brushes and springs.
Reassembly is a trick. Put the rotor back in the bottom bearing then bend back the retaining caps on the brushboxes, insert the brush and the spring, then while compressing the spring, bend the retaining cap closed. Next insert the rotor back into the stator, however when you do this, the magnet will try to pull the rotor out of the bottom bearing and you will loose the brushes so push your little finger through the magnet to control the rotor movement as you install it.
Simple.

Main bearings though, are shot, very noisy and rough. There are a couple of bolts holding a retaining clip which holds the bearings in place, this is awkward to remove without stripping the drive of all its plastics but a cut down BA spanner works ok.
Bearings are R4 types, one with a flange. https://www.bearingboys.co.uk/search.cgi?search=r4-2z have both at a not ruinous price. There were cheap ones on Amazon, but I really didn't like the look of them.
 
I have a new GW and just trying to get a compatible drive working (think I need mx strap but the only one I have doesn't have a jumper)

Fluxengine refuses to read a n* so I think you want a read with gw using the --raw method ?
 
Tandon drive rebuilt with new bearings in the spindle and a overhauled motor and it now runs smoooooth. Speed no longer jumps about and the disk reliably reads.

Just need to resolve the excess heat output now. A DC-DC converter to sit between the output of the rectifier and the 8V rail, but fully loaded the line has now fallen from 12V to 9.7V and thats getting close to not regulating. I dont really want to replace the PSU or the Tx with a custom wound unit.

The other possibility is some laptop fans blowing over the heatsinks I suppose. This system must have operated for some years as built without failing but the heatsinks get too hot to touch.
Not sure where to go yet :)
 
With my first 'microcomputer' (a Motorola 6800 D2) my external 5V linear regulator ran so hot (even with a large heatsink attached) I was a bit concerned.

I used to borrow a pan from the kitchen, half fill it with water, and rest it on the heatsink... Worked a treat!

Dave
 
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