1050 Troubles

[xrbrevin]

the power on self test sequence is as follows:

1. 6532 verification

2. WD279x internal function test

3. (E)PROM vaildation

4. RAM check

5. Error flag - if any of the above fail then drive motor spins for 2 seconds, then testing ceases

6. Track zero seek

 

here is a copy of the service manual, kindly rebuilt by one of the forum dudes. the above info is on page 2-2

 

yours doesnt even do the motor spin. as an aside, have the mech in another working 1050? but since you say the speedy worked, that requires removal of CPU and EPROM so i would check around those areas. if you have spare voltage regulators, maybe its worth swapping them over in case one or both is failing under load?

 

1050FSM-Rebuilt - AKH.pdf

[BillC]

11 hours ago, Technoid Mutant said:

The input to the 7812 is 12vdc and the output is 12vdc.

That can't be correct, a 7812 needs 2 to 2.5V of headroom to produce +12V. The 1050 has a diode(CR15) and capacitor(C71) which create a voltage doubler circuit to deliver sufficient voltage to the 7812, the 7812 input voltage should be around +20VDC.

 

There are modern LDO voltage regulators which can operate with input voltage only 0.5V higher than the output, but not the 7812.

[Jeffrey Worley]

1 hour ago, BillC said:

That can't be correct, a 7812 needs 2 to 2.5V of headroom to produce +12V. The 1050 has a diode(CR15) and capacitor(C71) which create a voltage doubler circuit to deliver sufficient voltage to the 7812, the 7812 input voltage should be around +20VDC.

 

There are modern LDO voltage regulators which can operate with input voltage only 0.5V higher than the output, but not the 7812.

Typo.  The input to the 7812 is 21 volts, that's 21.  How the circuit gets 21 out of 9vac is interesting.  Voltage doubler I guess.  Thank you Mr. Tesla.  ?

 

[+Nezgar]

On 10/16/2019 at 7:41 AM, Technoid Mutant said:

It worked briefly but then failed with no symptoms to hang a hat on but for a power led being on.  I think it may be killing CPU's.

This is also the symptom of a bad ROM or RAM. Can you verify the CRC32 of your US doubler ROMs? The only "official" ICD/FTe ROM i know of (so far) has CRC32 605B7153, which supports the 2797 controller. There are other variants though you can check against if it does not match.

 

On 10/16/2019 at 7:41 AM, Technoid Mutant said:

I also burned a doubler and tried that.  Just a power led.  I installed a stock 1050 rom and ram.  All known-good.  Just a power led.

Since the drive has a 2797 controller, ensure that when testing with a stock 1050 ROM you use the stock Atari Revision "L" code in the replacement ROM/EPROM. It should normally work with the US Doubler RAM module still in place, it just won't use the extra RAM available, and of course test with just a single 6810 as well then. Previous versions (ie H, J, K) only work with the 2793. Also if you switching between an EPROM and a mask ROM, ensure J1-4 jumpers are changed appropriately. JP1 & 3 jumpered for 2332 mask ROM, JP 2 & 4 for 2732 EPROM.

 

On 10/16/2019 at 7:41 AM, Technoid Mutant said:

The speedy brought it right to life, but then started flaking after a few minutes.  This is why I suspect power.  Under load the power situation may be quite different than in my static tests.

This makes me wonder if your RAM, ROM, CPU sockets have good continuity. Personally, I'd start by replacing those sockets with machine sockets. The original sockets may be corroded, no longer pressing with enough pressure, and are only single wipe. Especially after inserting a speedy PCB, as at least my boards have the really big square pin headers that compress the socket wipes so much they don't really work anymore with regular chips or round headers afterwards...

 

Of course, if power really is suspect, replacing all the small capacitors can't hurt either, which I see you are planning to do already... You can check the 5/12V DC sides for AC ripple with the "AC" mode of a multimeter, even better if you have an oscilliscope.

 

Just be careful if you ever swap the 2793/2797 controllers between drive PCB's that they end up back with their original PCB - there are adjustments on each PCB that are tuned specifically to each controller chip that was shipped with it.. Unless you have an oscilliscope and can re-calibrate for the replacement chip, you may end up with unreliable reads/writes especially in enhanced/double density (MFM modes). Further reading: https://atariage.com/forums/topic/282626-howto-adjust-analogue-part-of-fdc-279x-in-a-1050-disk-drive/

 

[Jeffrey Worley]

26 minutes ago, Nezgar said:

This is also the symptom of a bad ROM or RAM. Can you verify the CRC32 of your US doubler ROMs? The only "official" ICD/FTe ROM i know of (so far) has CRC32 605B7153, which supports the 2797 controller. There are other variants though you can check against if it does not match.

 

Since the drive has a 2797 controller, ensure that when testing with a stock 1050 ROM you use the stock Atari Revision "L" code in the replacement ROM/EPROM. It should normally work with the US Doubler RAM module still in place, it just won't use the extra RAM available, and of course test with just a single 6810 as well then. Previous versions (ie H, J, K) only work with the 2793. Also if you switching between an EPROM and a mask ROM, ensure J1-4 jumpers are changed appropriately. JP1 & 3 jumpered for 2332 mask ROM, JP 2 & 4 for 2732 EPROM.

 

This makes me wonder if your RAM, ROM, CPU sockets have good continuity. Personally, I'd start by replacing those sockets with machine sockets. The original sockets may be corroded, no longer pressing with enough pressure, and are only single wipe. Especially after inserting a speedy PCB, as at least my boards have the really big square pin headers that compress the socket wipes so much they don't really work anymore with regular chips or round headers afterwards...

 

Of course, if power really is suspect, replacing all the small capacitors can't hurt either, which I see you are planning to do already... You can check the 5/12V DC sides for AC ripple with the "AC" mode of a multimeter, even better if you have an oscilliscope.

 

Just be careful if you ever swap the 2793/2797 controllers between drive PCB's that they end up back with their original PCB - there are adjustments on each PCB that are tuned specifically to each controller chip that was shipped with it.. Unless you have an oscilliscope and can re-calibrate for the replacement chip, you may end up with unreliable reads/writes especially in enhanced/double density (MFM modes). Further reading: https://atariage.com/forums/topic/282626-howto-adjust-analogue-part-of-fdc-279x-in-a-1050-disk-drive/

 

Oh wow.  This is really good to know.  Like GTIA, you have to tune for normal variation between chips.  Got it.  I put the old chip back, but without a sillyscope, I'd be in pretty rough shape.  I am not even sure how to use one, though I'd learn pretty quick if the need arose.  Cross your fingers it doesn't.

[xrbrevin]

the drive i had that just illuminated the power LED was due to a ROM issue. USD mod fixed it.

[Jeffrey Worley]

3 hours ago, xrbrevin said:

the drive i had that just illuminated the power LED was due to a ROM issue. USD mod fixed it.

I'm gonna replace the sockets tonight and hope it is that simple.  I have a whole raft of parts coming in thier own sweet time, but I wouldn't cry if it turned out to be the old defective socket trick again.  ?

/s

 

Edited October 18, 2019 by Technoid Mutant
Clarity

[+Nezgar]

Another thought... if you replace the CPU socket with round machine pin sockets, and your speedy uses square pins, it won't go in (like Apollo 13?)

Edited October 19, 2019 by Nezgar
square PINS

[Jeffrey Worley]

2 minutes ago, Nezgar said:

Another thought... if you replace the CPU socket with round machine pin sockets, and your speedy uses square sockets, it won't go in (like Apollo 13?)

IIRC the Speedy's pins are round, but this drive came with genuine FTE US Doubler.  It worked for a few minutes, started flaking out, then bombed completely with just a power led and no other activity.  I suspected the ram, replaced that, and got nowhere, replaced ram and rom with atari parts, and got no where, replaced ram and rom with a known-good US Doubler of my own and got no where, left rom out and put speedy  in and got operation again, but it started flaking out after a few minutes and I pulled the speedy before something aweful happened to it.  I'm going to suspect the rom socket tonight and replace the others while I'm at it.  If that doesn't clear the problem, then caps are next.  I have all the small ones on-hand, the big ones are en-route.  I have spare 6507's and 6532's coming from China sometime in this century, and will use these to fix this drive, and/or an 850 I've got that has an identical problem (power led with no other signs of life).  I just got a working 850 from a buddy (THANKS Guy Ferante!), and can use the parts from this one to diagnose the one that needs the tlc.

 

Best,

 

Jeff

[_The Doctor__]

if the speedy started flaking out, did you start taking measurements at that point? sounds like somethings warming up and being silly, since you swapped as you did... support circuits are in play...

 

if voltages are all safe during flake out,

ice cold upside down aero duster could help you cool down the offending component... things will start to work better again... then you have the problem child's play room isolated.

Edited October 18, 2019 by _The Doctor__

[xrbrevin]

2 hours ago, Technoid Mutant said:

replaced ram and rom with atari parts

if your atari ROM has a sticker on it then it requires the same 4x jumper positions as the USD EPROM. it is as in the image.

if the 2x jumpers on the right are over to the right then it is only compatible with the PROM type (no sticker) and will not boot.

[Jeffrey Worley]

2 hours ago, xrbrevin said:

if your atari ROM has a sticker on it then it requires the same 4x jumper positions as the USD EPROM. it is as in the image.

if the 2x jumpers on the right are over to the right then it is only compatible with the PROM type (no sticker) and will not boot.

My Atari rom is a mask rom.  I tried it, knowing it wouldn't work, but still.  The drive must have had an eprom from the factory because the jumpers are in that configuration now and show no signs of ever being tampered with.  My own USDoubler won't work either, even though it is also an eprom, like the FTE unit the drive came with.  Some of my caps came today.  We'll get this sucker up and running if it harelips everybody on Cripple Creek.

 

Best,

 

Jeff

[Jeffrey Worley]

It is alive.  Checked the eprom it had, which worked for a bit when I first got the drive.  It is now BLANK.  I suspect it is dead.  I recapped the drive.  That helped a lot.  I found a bridge on the 6532, which I was no where near, so it must have been at some point in the drive's past.  A stray leg of something glommed onto the chip completely at random.  It came away with a fingernail's effort.  The drive works well now, is a teensy bit hesitant at formatting though.  I suspect that is the tuning that was discussed earlier.  Perhaps it will wear in.  I'm putting it through its paces now.

I burned a new USDoubler rom for it to get it up and running, with the one from FTE dead as a doornail.  My reader says it is blank, but won't program it.  I'll stick it outside on the treestump I use for an eprom eraser and see what gives in a couple of days once the other's I place with it say they are blank.

Good news, with the help of the link to the tuneup thread I did a little tweaking (Kentucky windage -- no sillyscope) and got it formatting like a champ.  I'm running it through it's paces now and it is just reading and writing like a champ.  I'm pretty sure it is done fixed.  Swapping disks from my other 1050's to and from it without trouble.  I'm happy.  Get it?  Happy?  Ok, it is a doubler, but I rather prefer the doubler, as the track buffer is a bit disconcerting with what it does to io sound vs head movement.  I'm so used to what a doubler sounds like it drives me a little wild to hear a happy at work.

 

Best,

 

Jeff

 

[+Nezgar]

Congrats! I know all too well all it takes to kill a 2732 is inserting it backwards... It even makes a nice conclusive visual flash if you're watching an uncovered window. Maybe your stray glommed leg caused the wrong voltage to go down the pin to do some  similar damage...

 

I agree that the USD seems 'closer' to what's really going on the disk and the drive. But I grew up both a USD and Happy... the happy was drive 1 and used with 'most' disks. The USD drive #2 was mostly for formatting and backing up to SpartaDOS data disks. It was nice the happy didn't skip a beat at all using ultraspeed interleave formatted disks...

 

Is your mech a Tandon or WST? (There's a patched USD ROM that faster for WST mechs.)

[Jeffrey Worley]

2 minutes ago, Nezgar said:

Congrats! I know all too well all it takes to kill a 2732 is inserting it backwards... It even makes a nice conclusive visual flash if you're watching an uncovered window. Maybe your stray glommed leg caused the wrong voltage to go down the pin to do some  similar damage...

 

I agree that the USD seems 'closer' to what's really going on the disk and the drive. But I grew up both a USD and Happy... the happy was drive 1 and used with 'most' disks. The USD drive #2 was mostly for formatting and backing up to SpartaDOS data disks. It was nice the happy didn't skip a beat at all using ultraspeed interleave formatted disks...

 

Is your mech a Tandon or WST? (There's a faster USD ROM for a WST mech.)

All three ( :-))) ) of my 1050's are tandon mechs.  Two are us doubles I made, one has the ram from FTE still, the other is a Speedy 1050 I aquired.  How do you RPM a Speedy?  It gives irrational numbers because it is pulling from the track buffer.  Is there a way to disable this feature for testing/calibration?

 

BTW, if someone really needs a drive, I'll be happy to let one go to a good home at a fair price.

 

[Jeffrey Worley]

5 minutes ago, Nezgar said:

Congrats! I know all too well all it takes to kill a 2732 is inserting it backwards... It even makes a nice conclusive visual flash if you're watching an uncovered window. Maybe your stray glommed leg caused the wrong voltage to go down the pin to do some  similar damage...

 

I agree that the USD seems 'closer' to what's really going on the disk and the drive. But I grew up both a USD and Happy... the happy was drive 1 and used with 'most' disks. The USD drive #2 was mostly for formatting and backing up to SpartaDOS data disks. It was nice the happy didn't skip a beat at all using ultraspeed interleave formatted disks...

 

Is your mech a Tandon or WST? (There's a patched USD ROM that faster for WST mechs.)

Oh yeah.  The interleave, skew, whatever, was sometimes a pain.  If you got a disk that was in the wrong format it could be a pain to undo it.  You'd have to read it in, real slow, then format for the correct skew and write it back out.  The happy is nice in this regard.  It doesn't use skew at all, does it all in it's head regardless of the order on the track.  The trouble for me in the 80's was that the happy and others like it were a LOT more expensive than the USDoubler, and you kinda had to have actual original media to copy to justify having one of the super mods.  I never came across a lot of original media that needed duping.

 

Best,

 

Jeff

[+Nezgar]

29 minutes ago, Technoid Mutant said:

How do you RPM a Speedy? 

The Speedy software disks have RPM and other diagnostic options, as well as other goodies like '1050 mode', copy tools (MS-copy), disk mapper shows sector interleaves, bad sectors, duplicated sectors, etc.

 

@Fox-1 / mnx's page covers most of the software: http://atari.fox-1.nl/atari-400-800-xl-xe/400-800-xl-xe-tools/speedy-1050-system-software/

 

Also here under "Mega Speedy ATR Files!"

http://www.realdos.net/MegaDownload.html

[+Nezgar]

32 minutes ago, Technoid Mutant said:

You'd have to read it in, real slow, then format for the correct skew and write it back out.

If only more sector copiers were intelligent like this to eliminate the pain of the first part: https://atariage.com/forums/topic/289018-us-doubler-ultraspeed-fastest-sector-reading-order/?do=findComment&comment=4235364

 

34 minutes ago, Technoid Mutant said:

the happy and others like it were a LOT more expensive than the USDoubler, and you kinda had to have actual original media to copy to justify having one of the super mods. 

Wot? I never had a genuine happy board until the last few years. Mine was acquired cheaper BITD as my dad had friends who were skilled in making their own clones.

36 minutes ago, Technoid Mutant said:

I never came across a lot of original media that needed duping.

We needed it for copying copy protected copies. ?