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Dead Laser 128 - no floppy drives work

SomeGuy

SomeGuy

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Joined
Jan 2, 2013
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Marietta, GA
Crap... was messing with the Laser 128 I was going to take to VCFSE tomorrow and it looks like it up and died.

Symptoms:
When powered on the drive spins but does not do the usual seek, and will not boot.
It will not boot from an external 3.5" drive.
When I load up prodos via ATDPRO and tell it to scan the drives, the internal and any external 3.5" or 5.25" drive spins for a moment but it does not list the drives at all so it won't format read or write.

Checked voltages on the external drive port and I think they look good.

I haven't tried plugging in a disk II controller in to the expansion slot, but I suspect that might function, but is not too useful.

No idea what happened, it had been working fine for about a month. It would be just my luck that the unobtanium disk controller chip is dead. I do have a spare 128 I'll use instead, but that really sucks.

Anyone encounter this specific problem before?
 
Throw a lil lube on the worm drive/stepper motor. Might be all it is. Try to spin it a little as well, needle noses with bandaids round em to not scar. Old 5.25s tend to get sticky when not used for a while.
 
I don't think is the head sticking, the drive was working flawlessly before this happened, the key thing here is the two external drives (3.5" and 5.25"), which I have already re-tested on the other machine, won't respond either. I'll do some more tests later on to make absolutely 100% sure. Also did a quick visual inspection of the motherboard and noticed nothing specifically wrong.

Are there any known tests to specifically check the functionality of the Laser 128's controller chip?
 
In a case like this video, perhaps the track 0 sensor is broken.
As an interim measure, the sensor can be disabled by disconnecting the sensor connector and shorting it out. I have repaired three Laser 128s this way.
 

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The drives pull a bit of power
Try plugging the disk controller and drive into the slot.
If that works then you're pretty sure it's not a power supply issue
 
ushicow said:
In a case like this video, perhaps the track 0 sensor is broken.
As an interim measure, the sensor can be disabled by disconnecting the sensor connector and shorting it out. I have repaired three Laser 128s this way.
Click to expand...
Thank you very much, it was exactly what happens with my Laser128, I have bypassed the sensor and it works.
 
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