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XF551 Small update



Just a small update:  I recieved what I hope is the last prototype boards in yesterday.  On these I’ll be testing the full blown board operation including the alternate osc circuit, front panel mods and the fit and trim of the boards.  I’ve started installing the parts tonight.  Hopefully I’ll have a ready to test board in about three days.   At this point I still am employed, so that has to come first.  🙂

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XF551 Updates



I have to tell you I have been riding on the leftover euphoria of finally getting the XF551 board working for the last couple of weeks.  I know it’s sad.  A thirty something year old piece of equipment kicked my butt for almost two years.  But heck you try to get it working when you have only a draft set of schematics from Atari missing parts info,  a error filled set of schematics from sobra, no Sam’s booklet, a sometime working physical drive unit, and the need to school myself on two different pcb softwares, less than part time time to work on it and all the normal drama of simply living.  Alright…. alright I’ll shut up.  Smile

I have been working on cleaning up the schematics, making it pretty and creating the fully implemented board to test all the mods with.   I send that off to the board house along with the front panel display/switch board hopefully by Monday.  I should have the boards in in about 2 weeks.  A few days to solder the board together and test and cross my fingers I’ll be able to offer the boards for sale.  Just about two full years after I started this crazy idea of a summer project.  Who’da thunk?

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XF551 Updates – Basic Board is Working !!!


I have not completely ceased working on the XF551 board.  Contrary to my earlier  announcement.  Damn thing has a hold on me.  Yell  My last board has yielded some positive results.

I went back to square one so to speak.  I decided to design a board with just the bare essentials necessary.  Hopefully to eliminate possible complications due to the mods I wanted to incorporate.  It reduced the board space needed and therefor also the cost to manufacture.

On the last test my previous board had failed the drive power on test.  I had the data cable on wrong and the cable itself was not made right.  I replaced the cable.  Then after retracing the board traces I found some mistakes.  That’s when I decided to go bare essentials.  A few weeks later new board in hand I proceeded to solder in parts.  Soldering complete, I inserted my chips. Did a fast power on test and no billowing smoke or loud pop.  Good….    Then I attached the new data cable and drive and powered on.  I was able to get the drive to spin up briefly when powered on, just like the original.

I began to get encouraged.  I plugged in the SIO cable from an functioning 800XL.  Powered the drive and then the 800XL and the drive light comes on and stays on.  The 800XL beeps and displays ‘Boot Error’. Well… not exactly success, but it tells me that the computer is seeing the drive and communicating with it.  At least to some degree.  The drive is not spinning, or attempting to seek.

So now I start looking for possible problems with chips and drive.  I replaced all the chips except for the ROM and now the drive attempts to load.  It gets about a third into the load sequence and then the drive starts chunking every few seconds.  Okay,  a little further down the road.   What if the drive is bad?  So I replaced the drive and now it’s singing.

I just about fell down and kissed the ground.  So for the record I have a very basic mainboard using a modern power supply and it is loading a DOS 2.5 disk.  Here’s the YouTube videos I made.

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Sea Change Update


Well,  it’s been almost a month since my last post.  Perceptions have changed, expectations have risen and fallen with the tide.  I am still employed, but the countdown has begun.  On or around May 4th I will cease being an employee of my current company.  I have applied for another position in the company.  It would involve relocation to Phoenix.  So far there has been no job offer after the interview.  My hopes are beginning to fade.


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Major sea change happened today……..


Went into work today, expecting it to be just like any other day of the week.  I was so wrong.

It was the first day back after my ‘weekend’ off.  Funny…. I haven’t had a weekend off in so long I’ve forgotten what they are, at least the traditional ones.  But I digress.

I noticed the increased security presence, but thought maybe it was just the changing of the shift.  The call center seemed to be missing some people even at the early hour I start.  Again I didn’t think to much about it, the night crew is not very big in numbers anyway.  I sat down at my desk and began logging in, prepping for the first call of the day.   Since I had been gone two days I usually go to my email to catch up on what has been happening.  Most of the time it’s minor policy changes and silly contests to see who can sell the most this day or week.

All of a sudden I started to see emails from VP’s and GM’s popping into my inbox about some VERY important meeting that was going to take place that day.  Everyone in the call center was required to attend.  Well that meeting took place yesterday.  Finally the last high profile email from the GM popped in and I opened it up.

Now understand I am a veteran of losing jobs.  Some through no fault of my own and some because someone thought I’d done something wrong.  It comes with the length of life.  And it comes to all of us at some point or another.  I reached a zenith (or rather the pits) about twelve years ago during the dot com crash.  I had started a new job with this webhosting company, monitoring their servers and dealing with hiccups on an as needed basis.  I’d been on the job about a month working the graveyard shift.   It was New Year’s Eve.  I was at home just a few hours before going into to do my shift.  I get a call from my boss.  She was calling me to tell me not to come in, not that night and not ever again.  Oh and by the way the company had filed for bankruptcy that morning.   What I didn’t know at that time was the paycheck that had been deposited into my checking account just that day from the previous two weeks of work would be yanked out and returned to the bankruptcy court.   Effectively I not only didn’t have a job, but now my checks for rent and utilities were bouncing because of that.

Fast forward to now.  I’ve been with this company for nearly twelve years.  It’s had it ups and downs, but I am not ready to quit just yet.  Not my choice anymore.

The company is restructuring.  All billing and tech support positions in the local call center are going to be eliminated.  Sorry, but that’s what we decided to do.  Oh and by the way please continue to take calls and do not mention any of this to the public.  We’ll get back with you with more details.

Not quite as bad as that New Year’s Eve, but certainly not one of the better days of my life.

What does that mean to you?  All development of the XF551 and other products are on hold immediately.  If I want to stay with the company it means relocation and all the chaos that goes with it.  Right now I need to focus on surviving.  I will continue to sell what I have in inventory, but I don’t know if I will be able to replenish any time soon.  If it becomes clear that I will not have the financial resources to continue I will hand off the work and parts.  Maybe someone else can continue after me and bring this project to completion.

The shock still has ahold of me.   Be thinking of me.  Hopefully I will return.  Be thankful if you have a job.





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XF551 Update


I’ve resisted updating for the last couple of weeks.  Partly out of depression and partly out lack of time.  Lets get the bad news out of the way right now.  It’s a mixed bag, but there is some hope.

As I last reported the power supply seemed to be working and no fizzes, blue/black smoke or loud bangs to signal fatal failure.  I then proceeded to make the power and data cables to go from board to drive housing.  I verified pin to pin as best I was able to that my cables matched and mated with the originals.   As I placed them on the board it became apparent that some design assumptions would have to be changed.  Nothing fatal, just some more research and parts sourcing.

Then I placed the board into the case.   The fit of the board in the case is near perfect.  A tiny adjustment here and there and that part of the project is done.

DSC_1715M    DSC_1716M

Then I fitted the drive housing on it’s piers.  It fit and layed flat, but I could see barely a few mils between the OS chip in its socket and the bottom of the drive housing.    The bottom of the drive housing is not filled flat.  There are large open spaces around the spindle and drive motor so depending on the height of the other parts not installed yet I could have a fit issue between the board and the drive housing.  Or not.  Certainly something to think about.

After connecting the power and data cables I was ready for the acid test so to speak.  Would the drive/new board behave as the original?  Remember there is no connection to a Atari computer at this point yet.  I tested first the reaction of an original drive with only power applied as a gauge.    The power light comes on briefly and the motor seems to spin up and then come to rest, the power light goes off.  If I could get my board to do the same, then I could proceed to the next step of checking SIO signals from the connector to see if there was any danger of foreign voltage on the connector.

I pressed the power switch on.

The power light came on and the drive spun up.  And kept on spinning and spinning and spinning.  The light stayed on.

I turned the power switch off.

At least the power switch worked.  The power light went out and the drive stopped spinning.  Conclusions were that yes I had the power cable right.  But I couldn’t say for sure much else was right.  Two areas I began to investigate– 1) reexaming the board schematics to see if I had pins connecting to the wrong part (I swear I am beginning to see these schematics in my sleep) and 2) data cable mismatch.  I found errors in both.  The data cable I could fix immediately but I had run multiple pins to the wrong parts.  Perhaps a hold over from the Eagle design days.  That was not so easily fixed.

Coupled with other design changes I intended to make I decided to make one more proto board.  That new board should arrive next week.  Look for an update around the first week or two in March.

PS Feb 25 — The protoboard arrived today.  Along with the first proto of the front panel board for the led display and drive select etc.  I probably won’t come up for air for at least the next two days or so.




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Another use for MMU Adapter (Cart Dump Hardware)


While perusing the internet recently I came upon this old gem.

Interestingly of the methods talked about to create a hardware cartridge dumper one of them is possible with my MMU Adapter by simply connecting four wires and a DPDT switch.  I have tested that the hardware modification works, but then it becomes a question if the software(The Cartridge Dumper utility) created by Jindrich Kubec to dump to a file will work.

So far I have had little success in operating the software as is claimed in this internet article.  A thread on AtariAge seemed to indicate that the little utility was never really meant for public use and therefore left much to be desired as far as user friendliness.  I would have to agree.  Perhaps someone can tinker with it and/or create a utility that will be more friendly to use.

There are other means to dump a cartridge to a file, and little reason to now as most carts have been dumped and are available for download.  But the tinkerer in me likes to make my own just to see if it will work.

I have added the schematic to the MMU adapter documents.

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XF551 Update


Recieved what I hope is the final proto boards in Monday.  Over the last few days I have soldered in all the essential parts.  Not the front panel mods.  That area is still in development and could change.  But all parts necessary for the operation of the board have been soldered in except for the power and data cable for the drive.  I have power tested the board and nothing blows up, some chips get warm but no sauna chips and no exploding caps or resistors.  Since there are no Sam’s manual for the XF551 and therefor no documented measurements I can check against, that may mean nothing at all, but I am cautiously optimistic.  Smile

Next up is the attachment of the power and data cables for the floppy and the installation of the board and drive into the case.  Then the next major test is the power up w/o connection to the Atari.  Does the drive power up like a normal XF551?  Is there backfeed through the SIO connectors etc? I don’t want to fry an Atari computer.

I am using the modern format XF551 to test with.   It should prove the hardest to get up and running.  What I learn here on this one will allow me to get the original setup quicker.  I suppose I could have gone the other way around but I only had enough money to send 1 board format to manufacture.  $80 for 5 boards 15cm X 15cm plus shipping.   It ain’t cheap.  Frown

Next update should come by the end of this next week.




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XF551 Update


Decided against doing the OSC and LED test boards.  The OSC mod just allows a 33.333MHZ OSC to be used instead of the Atari specific 8.333MHz.  Igor has already tested his LED mods.  So I sent what I hope to be the final proto board to the board house.  I should get it in sometime next week.

I have to say that using the Diptrace PCB software is such a joy after struggling with Eagle for the last two years or so.  Even the free/trial version is light years ahead of Eagle.  I will never go back.  Maybe it’s because Diptrace acts like a Windows app and Eagle like the DOS based program it is with a Windows 3.1 GUI tacked on.  Sorry about the dig, but I stopped using Windows 3.1 about 20 years ago.   Atari is the only retro I want to do now.  🙂

In the mean time I am sourcing parts and trying to shave as much cost off the board production as I can without losing quality.  Right now it’s looking like the board costs are running around $80.00 for the basic board with $20 more getting you the front panel parts and boards.   Stay tuned.



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XF551 Update



[dropcap]O[/dropcap]kay time for an update.  I recieved the modern power supply test board about a week or two ago.  Soldered everything in and it is working with a 24V 1.5 A DC wall plugin.  So that is a big step for the modern version of the XF551.  I am currently about ready to send the alternate osc circuit and the LED test boards to Itead for manufacture.  In about two weeks or so when they come in I can test them and if they pass, that’ll be the final phase before sending the complete modern XF551 board in.


Not so good for the original power supply test board.  I got the test board in yesterday and finished soldering the parts in tonight.  It didn’t blow or let out black smoke but there is no voltage at the drive connector.    I know the Atari transformer is working because I can power a 1050 with it.  So either I wired the DPDT switch wrong or something else in the wiring is wrong.  So it’s back to the schematics to see if I can rewire the test board to see if I can get it to work.


Yipee!  It was in the schematic.  Had the switch wired wrong.  Cut the wrong trace and wired it right.  Success!!!  Now both the modern and original power supplies are working.