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Arcam Alpha One Problem
Arcam Alpha One Problem
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Old 16th November 2017, 10:24 AM   #1
Mikecamer is offline Mikecamer
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Default Arcam Alpha One Problem

Hello
I have one of these and having had issues with recognising any discs and spinning up only occasionally.
I have replaced the Sony KSS 240A laser pickup and greased all the moving bits that had grease on originally.
The mechanism lifts on loading but sticks 2/3 of the way up ,it will raise fully with a nudge but seems quite stiff. However it still fails to spin the disc. The little laser window goes up and down in it's housing sporadically but that's about it. Should there be any light coming out of the laser ?
Is it worth replacing the drive belt ?
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Old 16th November 2017, 08:18 PM   #2
Mooly is offline Mooly  United Kingdom
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Arcam Alpha One Problem
Yes, the drive belt operating the mechanism could well be stretched if the loading cycle does not complete. The laser light is near infra red and so not easy to see. It will only be visible during the couple of seconds the lens performs a focus search operation when it determines if a disc is present.

This details a KSS240 based player:
Sony CDP790 and KSS240 Restoration Project
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Old 16th November 2017, 08:31 PM   #3
Mikecamer is offline Mikecamer
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Quote:
Originally Posted by Mooly View Post
Yes, the drive belt operating the mechanism could well be stretched if the loading cycle does not complete. The laser light is near infra red and so not easy to see. It will only be visible during the couple of seconds the lens performs a focus search operation when it determines if a disc is present.

This details a KSS240 based player:
Sony CDP790 and KSS240 Restoration Project
Thank you Mooly
My other concern is that the cd doesn’t start spinning when the transport is “helped” into the correct position and engages the cd
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Old 17th November 2017, 07:58 AM   #4
Mooly is offline Mooly  United Kingdom
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Arcam Alpha One Problem
You have to be sure all the basics are correct before looking deeper. A good test is to manually move the pickup away from the normal rest position and toward the disc edge. Do that with the player off, the drawer open and no disc present. When you turn on the power and press play (or close the drawer) the pickup should move back to the normal rest position, the drawer and mechanism should smartly complete the loading cycle and then the lens should move up and down three times as it searches for a disc to focus on.

If all that happens correctly then it may be worth taking a chance on replacing the pickup although ideally further more involved tests should be carried out.
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Old 17th November 2017, 08:17 AM   #5
Mikecamer is offline Mikecamer
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Thanks Mooly
I have replaced the pickup and it does all of the above but the motor doesn’t spin
I guesss it’s worth another 7 quid to try a new drive belt before giving up
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Old 17th November 2017, 08:31 AM   #6
Mooly is offline Mooly  United Kingdom
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Arcam Alpha One Problem
If it really does do all that then the loading cycle sounds to be completing and so you are probably looking elsewhere. You have to be sure in your own mind though that the mechanics are OK.

You should be able to detect light from the laser during that couple of seconds the lens moves up and down but it will be faint. You need to look from a distance of around 20 to 30 cm's away and very slightly off axis. The disc will not spin until focus is found on the reflective surface.

Other basic checks would be to confirm all the supplies are correct (make sure there are no obviously bulging (vent split open) caps in the power supply. Supplies should be checked with an oscilloscope to ensure they are clean.

The spindle motor should be quickly checked to make sure it is free and not sticky.
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Old 17th November 2017, 01:54 PM   #7
Mikecamer is offline Mikecamer
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I must admit I'm a bit stumped now.
The mechanics all seem to work Ok but I can see nothing from the laser, it does go up and down. I've tried a replacement too. the disc loads but fails to spin up.
May have to give up on this one
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Old 17th November 2017, 02:39 PM   #8
Mooly is offline Mooly  United Kingdom
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Arcam Alpha One Problem
Another check of the lase can be done with viewing it via a digital camera or phone. The IR light should be very obvious. Try pointing a remote control at a camera to see how it looks.

If its not doing that, and seeing as this is the second pickup then yes, the trouble is much deeper seated.
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