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Atarisrule

Atari 1050 Drive - Power, no action

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The drive powers on but does nothing. When switched on the lower red switch light comes on but the upper "activity" light never comes on and the drive never moves. I have another 1050 that does work great so I know what it should be doing. Also the computer never recognizes the drive is there if it's hooked up - I just get the Memo Pad. Not so with the good drive - it talks perfectly with the computer.

 

I've read through all the posts I could find and did some work on the drive, but nothing seems to have worked. I've replaced the two rectifier diodes and the three large caps and the two small ones below them. The regulators are putting out 5V and 12V like they should from the right hand pin so I didn't replace them. Nothing gets really hot or anything, but I did notice the heat sink/shield that the regs are attached to did warm up when I had the power supply attached.

 

So, short of throwing this to the parts bin, what else can I try? It's starting to cost more than it's worth just in repair parts.

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A little more info. Random checks throughout the main board show correct voltages. Also I have 12V in both red wires of J15 going to the drive body. Still no activity light. No feedback to the computer.

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Try gently lifting and replacing the socketed chips. Sometimes they work loose or get oxidation on their pins.

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Try this: Open both drives, the good one and the bad one.

Swap out chips one by one from the bad one into the good one until the good one quits working. When the good one quits working, the last swap you made is the bad chip.

 

 

Start with the CPU, part # CO10745 / CO16145

then the 6532, CO10750 / CO16150

then the ROM, FC100541 / 2732

then the 6810 RAM, CO14328

then the FDC, FC100542 / FC100817 / 2793 / 2797

 

Don't mix them up, if a swap makes no difference, put it back and try the next. The part#s are to the best of my knowledge, yours may or may not be the same.

 

It may be something else, but if you tested the power supply section, a bad chip seems likely to me, especially since it's not going through the normal 1050 error routine of light on and spin, pause, light on and spin, pause, repeat forever.

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The 3086 chip(U1) is between the SIO ports and the 6532 and is prone to damage if the 1050 is unplugged while powered up, this is a likely cause of the problem.

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The 3086 chip(U1) is between the SIO ports and the 6532 and is prone to damage if the 1050 is unplugged while powered up, this is a likely cause of the problem.

Replaced a few of these myself!

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The 3086 would only affect SIO activity. The drive doesn't even seem to be booting up fully. I would also check first the CPU, RAM, ROM, RIOT.

 

Also - don't bin the 1050, send it to someone willing to fix it! I hate to see old tech in the garbage!

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Correct. With no SIO connection to anything, just powering on the drive it does nothing but turn on the power LED. It should cycle the head and drive but there is no activity at all. Whatever circuit is supposed to tell the drive to do that is not functioning or is blocked.

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6532 RIOT chip in charge there, but no easy way other than swapping with known working one to know if the problem stems from before this point. It controls both the drive motor which also lights the activity light and head stepper motor. Nice to know it's got decent voltage to work with, as stated it's NOT booting correctly, swapping chips out is a fast way to find out which one it is. Time to get a 2nd drive opened up?

 

From Photofact, your mileage may vary. PIA here is 6532 RIOT.

post-13325-0-47185100-1427470706_thumb.jpg

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The drive powers on but does nothing. When switched on the lower red switch light comes on but the upper "activity" light never comes on and the drive never moves. I have another 1050 that does work great so I know what it should be doing. Also the computer never recognizes the drive is there if it's hooked up - I just get the Memo Pad. Not so with the good drive - it talks perfectly with the computer.

 

I've read through all the posts I could find and did some work on the drive, but nothing seems to have worked. I've replaced the two rectifier diodes and the three large caps and the two small ones below them. The regulators are putting out 5V and 12V like they should from the right hand pin so I didn't replace them. Nothing gets really hot or anything, but I did notice the heat sink/shield that the regs are attached to did warm up when I had the power supply attached.

 

So, short of throwing this to the parts bin, what else can I try? It's starting to cost more than it's worth just in repair parts.

Very simple and probably way off base, but you will get this problem if jumpers 1-4 are not properly arranged for an EPROM or ROM chip (equals no OS if set wrong). A ROM will have 1 and 3 jumpered, and the other two open. EPROM will have 2 and 4 jumpered and 1 and 3 open. I have seen this movie tooooooo many times (I'm having the same issues). Good luck.

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What jumpers? I will swap chips and see what happens.

Right behind the OS ROM (U 10), you should see 4 little white jumpers...they almost look like fuses. Jumpers 1-4 are the only ones to be concerned about. If jumpers are 2 and 4, this is setup for a 2732 EPROM (EPROM has the little window. ROM's do not have a window, but they have also used a 2732 ROM that uses jumpers 2 and 4.) If the jumpers are 1 and 3, it is set for a 2332 ROM. You can change the jumpers with a little soldering (I had to do this on one). It can be very confusing and seems to be outright stupid. Good luck.

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Solved! One by one okay except the last. The WD2793PL-02 chip is bad. It killed the good drive and the replacement woke up the bad drive. Now to source one. Any ideas? The chip sources I have links to do not show this chip, or at least not by this number. Is there an Atari number for this? It is the 40 pin chip all the way to the left.

 

Edit: I see this is the Atari FC100542 and Best has it for $15.95. Does anyone have a spare from a dead drive?

 

post-41831-0-05709900-1427513810_thumb.jpg

Edited by Atarisrule

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I have one for $12.00 delivered.

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I ordered one from Best Electronics this morning. If that falls through I'll take you up on the offer. I had some other stuff to order anyway so this took me over the minimum shipping threshold.

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Whats the best way to pull these chips out as have same problem with mine and i want to try the same process. The chips are a little tight in the sockets , i dont want to risk breaking the pins

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Try this: Open both drives, the good one and the bad one.

Swap out chips one by one from the bad one into the good one until the good one quits working. When the good one quits working, the last swap you made is the bad chip.

 

 

Start with the CPU, part # CO10745 / CO16145

then the 6532, CO10750 / CO16150

then the ROM, FC100541 / 2732

then the 6810 RAM, CO14328

then the FDC, FC100542 / FC100817 / 2793 / 2797

 

Don't mix them up, if a swap makes no difference, put it back and try the next. The part#s are to the best of my knowledge, yours may or may not be the same.

 

It may be something else, but if you tested the power supply section, a bad chip seems likely to me, especially since it's not going through the normal 1050 error routine of light on and spin, pause, light on and spin, pause, repeat forever.

Whats the best way to pull these chips out as have same problem with mine and i want to try the same process. The chips are a little tight in the sockets , i dont want to risk breaking the pins

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