Posted By
SVS
on 2002-07-16
 |  Again 1551 fault.
Well, my friends, first I thank you for your tips.
Besides the 4 blinks signal is not performed during the start-up of drive (as I wrote).
I have it when I hit "diR". Then on the screen I have "65535" and sometimes 2/3 garbage chars.
The drive starts blinks (4 - pause - 4 - ...) and goes frozen till a reset.
I tried to change the ROM, but noway 
Any ideas?
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Posted By
BushRat
on 2002-07-16
| Location?
You cleaned the interface contact strips by burnishing them with either a pencil eraser or a clean piece of paper(be sure you are grounded from static). Check and carefully clean the read/write head and also make sure the felt pressure pad is still there. Of course, none of this will account for your error blinks... I wonder if you might be doing the same thing that forced me to re-copy a couple hundred disks a few years ago...
Make SURE that you don't have the drive or the cable near the LEFT side of your Commodore monitor or for that matter ANY monitor! The high voltage transformer is located there and produces VERY large frequency pulses that will SKEW data badly on either read or write. My monitor was sitting on the top shelf of my work desk and the drive was below and under the monitor... what a mess. I could read the disks I copied, but were read errors on another drive, because the data was written skewed.
I would get the same type of garbaged Dir on read, on my 1551 (with blinks and freezes), until I finally moved the drive a cable away from ANY monitor.
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Posted By
BushRat
on 2002-07-16
| Lube those rails, too
Commie used a white Lithium-based grease.. if you don't have, use VERY light coat of Vaseline petroleum jelly.
By the way, you booger... you have the 840k ungrade? You like? I had my 256k from Peter and Christian sent me one, back when we were all hot to write support on the expanded machine and for the sidcard/blaster combo... remember?
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Posted By
JamesC
on 2002-07-17
| SVS -->
change the circuit board with the other 1551 board.
Jim --> Contacts cleaned on my 1551; I can play Jack Attack through the 1551 connector. Still hangs at end of disk access when doing a DIRECTORY, then system hangs and even a reset won't allow disk access. No error blinks on bootup, and no listings in 1541 diagnostic manuals cover this condition. Any other ideas? (The 1551 is 18 inches to the right of a 1702 monitor, with the Plus/4 sitting in between. However all are plugged into the same power strip. A 1541 in place of the 1551 works fine.)
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Posted By
BushRat
on 2002-07-17
| Hmmm..
Could be a flakey PLA chip or the expansion slot. I don't have access to my 1551, packed away, but check to make sure the carrier/track stop sensor is clean. You should see the optical stop sensor off to the side of the rails and a tab that interrupts the led/detector. if there is dust or crud that has settled on it... it can't reference the tracks or alignment properly. Also, look under the 1551 utils and you should find a speed checker. See if the disk is turning at close to the proper speed. Also, clean with alcohol the hub that the floppy sits on and the bottom edge of the plastic spindle, above. See if the splindle rotatates freely and lube where it passes through the top metal bracket. Finally, check the tension on the read/write head tension spring (at the rear of the head arm assy) you may have to bend it a bit to increase the head pressure on the floppy.
Good luck...
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Posted By
SVS
on 2002-07-18
| Thank you boys,
but I'm still stopped. I checked all socked ICs and cleaned all connetors but noway! I'll try to substitute the electronic of first drive with that one of the second drive, as James suggests.
James --> I experienced the problem you speaks (stop at end Directory). If you have connected the X1541 cable, unplug it and try again. Wait for your reply.
S\_/S
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Posted By
JamesC
on 2002-07-18
| Not the X-1541 cable
because that's on the PC in the bedroom. The Plus/4 setup isn't even in the same room. The 1551 acts like it can't calculate the blocks free message, because it displays the whole directory up to that point.
But the weird "DEVICE NOT PRESENT" errors upon pushing the reset button or turning the power off and on on the 1551.... still have those. NOTHING is plugged into the serial port. No 1541, no printer, etc.
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Posted By
BushRat
on 2002-07-18
| Optical stop
I could duplicate the directory read errors, you are describing, on my 1551 that I dug out. I had to move the optical stop block, to intentionally mis-align the drive. The mech assy in mine is a Newtronics, from a 1541. The original drive assy and the other 1551 board are with Dave Cook in California. This is my secondary unit that was simply a 1551 board that I mounted in a 1541 Newtronics case. Luckily, I've not had a problem with it. I snapped a few pix and uploaded them to my wife's page at:
http://home.gci.net/~ace/files/
They show the mechanical and optical stop assemblies, along with the motor speed adjustment control (the little blue adjustment control). If you loosen the two holding screws on the black optical stop assy and nudge it (just slightly!) toward the rear of the case, you may cure your problem... if it is alignment. The optical stop was installed to prevent the hammering that the Commie drives used to go through, when trying to align themselves after a fault and during initialization. If the optical stop is too far forward, the drive thinks it has reached the end of the head travel before it actually reaches the true mechanical stop. That can result in the drive being "soft misalligned" and can make the reading of track 18 (the directory track) difficult. Remember, that Commie screwed up by allowing the "rest" position of the read/write head to be at track 18. That is why we all learned to avoid turning the drive on or off with a floppy inserted and the head locked down (unlike PCs) the turn on/off cycle produced a pulse at the R/W head and easily garbaged (blew) the directory. Funny how this stuff sticks in one's head after all these years.
This may not be your answer, but worth a check. Don't hesitate to try a new drive assy from a true 1541 (the white unit shown in one of the pix) as long as it is a Newtronics (not the
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Posted By
BushRat
on 2002-07-18
| This got cut off..
Not the click-down door Alps. I also found that I had problems if I had a 1541 II drive on at the same time. If I switched the 1551 to device 9 and the 1541 II to device 8.. they went away (hardware switched.. not software).
worth a try
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Posted By
SVS
on 2002-07-20
| 1551 device set to #9 works only if you have another 1551 as device #8.
It never works if device #8 is a 1541, I think because of the cartridge plug of 1551.
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Posted By
JamesC
on 2002-07-20
| Device Numbers
A 1551 has priority over a 1541 if both have the same device number. If you have a 1551 and a 1541 both attached to the system as drive 8, the 1551 will be used and the 1541 ignored.
When they have different device numbers, they should behave fine.
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