That was my first thought but the first thing I did was to clean and re-lubricate the tracks which didn't help. Also, as noted earlier when powering up and finding the home position there is plenty of power. It is only when returning from the scan that it is so easy to stop. Hence N_Cook's suggestion about micro-stepping.
Hi Andrew,
I have the LS-2000 scanner. I had some scanning troubles with mine as well though I can't remember if screeching noises was one of the symptoms. Not only did I clean and lube the rails, I removed anything in the transport that moved and made sure nothing was sticking. I think you'll need to remove that plastic pulley shown on page 6 of your pdf and make sure that isn't sticking as well.
Good luck.
Would seem to indicate nylon wheel or it's axle binding somewhere.
Looks as if it is intended to take up any slack that develops in the lead screw/nut.
HTH.
DerekG
Well, I got a chance to do some more tests at the weekend. Basically there appear to be three [1] speeds at which the carriage can move, Fast, medium or slow. It moves on rails between the front (F) and back (B) of the unit.
On power on:
F->B fast - lots of power B->F fast - to home position lots of power
On preview:
B->F medium - preview scan, lots of power F->B fast - return to home position, can be stopped with a finger
On scan: B->F slow - scanning, lots of power F->B fast - return to home position, can be stopped with a finger
So it seems that the power that the carriage has is not related to how fast it is going but how fast it has been going. These tests were all done with the spring removed so no interference on that front.
I am at a loss to see a connection between speed and power unless there is micro-stepping involved in the preview/scan which leaves the motor in a position where the return is underpowered. But what would be the root cause?
Does the team have any further ideas of where to look next?
Thanks for everyone's input.
Andrew
[1] specifically there is a range of speeds depending on the preview/scan resolution selected.HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.