One Last EPROM

[DavidMil]

This is the last of the EPROM's that I found in a box (yes, in the attic).

Here is what it looked like on the burner:

.

-593241 © 1984 ICD

 

This is a 2732 Chip

 

I've included the dump too.

Any Ideas?

 

DavidMil

ICD.BIN

Edited February 4, 2018 by DavidMil

[+Nezgar]

Interesting, comparing against the 1050 USDoubler ROM, it starts out with exact same header, first Diff is at $1A,$1B, then $43,$44, $46, $49, $4C, $4E, then pretty much different past that.

 

Near the end of the ROM, $0FA8 is the text " DISK ERROR "

$0FB9 "START to restart"

$0FE5 "SPACE Change item"

 

EDIT: I see these 3 same strings in the working USDoubler 1-4 ROM as well. This appears to be a variant of US Doubler.. maybe corrupt or, the drive # 5-8 version?

 

EDIT 2: the 2 compare exactly the same from $0942 to the end

 

Guess I'll have to burn it to a 2732 and try it

Edited February 4, 2018 by Nezgar

[+Nezgar]

Just for the heck of it I dumped the US Doubler EPROM that I've been using in my 1050 since the 90's (my dad had burned it from some source of his own), and compared it against the USDBLR.ROM i've found online. Dumping using the dropcheck Ralf-David board, I get 1 byte different in my ROM at $0F00, reading $00 instead of $2C in the download. It seemed to work just fine, so not sure if thats an error in the read, or a non-essential byte...

[+Nezgar]

Came across this post, noting there was 2 versions of US Doubler (other than the 1-4 and 5-8 versions): for mask rom dives, and eprom drives, so you could upgrade without having to re-position the jumpers. Unknown if the ROM content differed: http://atariage.com/forums/topic/158129-1050e-and-icd-us-doubler/?p=1954449

[Kyle22]

This is the last of the EPROM's that I found in a box (yes, in the attic).

Here is what it looked like on the burner:

.

-593241 © 1984 ICD

 

This is a 2732 Chip

 

I've included the dump too.

Any Ideas?

 

DavidMil

The 3241 in the beginning can be changed to 7685 to make it a D5: - D8: USD.

 

Burn it on a 2532 if you want to replace a Mask ROM, 2732 otherwise.

[1050]

USDoubler - but different from what I have.

 

Perhaps this is the rom used by _The Doctor_ when he

claims to have used it without the stacked ram and it

'worked just fine'?

 

Later versions included the extensive ram test that

I know would not allow such standard and single ram

chip use.

 

Mine starts with 1Dh and not FFh, have 2Ch at 0x0F00

offset too. But then blocks shift around such as to

indicate a change up in the source code at the very

least. Which begs the question why do that? Perhaps

the need for the more better extensive ram test?

 

Was never aware that there were two versions, but it

does appear to be the case for certain now. Thanks for

posting that as it's very interesting stuff.

 

They both deserve a disassembly at this point to

figure out what up and maybe why becomes obvious.

[+Nezgar]

I successfully burned this to an EPROM, and it works! Sort of. It seems to use a head stepping speed that's way too fast for my mechs. I'm going to try to post a video shortly before it gets too late so others can observe.

 

If you're familiar with the normal US Doubler POST, quick head seek forward/back that is shorter (fewer steps in/out) compared to a stock 1050 ROM. This ROM seems to attempt the same thing at POST, but its more of just a fast blip of forward/back stepping. I was able to get it to reliably read track 0 of a SD and a DD disk as long as I didn't allow it to read read past sector 18 where it would try to step to the next track. Track 1 might partially read, track 2 unreadable do to the incomplete stepping.

 

While disk ejected, if i manually slide the read head up to 75%/track 30 ish, and then close the door, the usual behaviour is to seek to track 0. This does that, but in a very jittery fashion until track 0 is sensed.

 

The behaviour is the same when trying this ROM in both a Tandon and a WST mech drive. I recall hearing that the ROM for the later WST drives (Rev J? K? L?) had a faster stepping rate, so I thought to try it with the drive with that mech in case this was an updated ROM intended for 'newer' 1050's. Maybe there's another mech variant this is compatible with. My WST 1050 was upgraded to a Happy very early in it's life in the 80's and I don't have the original ROM any more to compare. I guess I could try burning one.

 

This ROM also requires the usual 2x6810 RAM stack, it will NOT pass POST with only 1. If there exists such a US Doubler ROM that works with a single 6810 (even just for SD/ED) I'm very interested to find it.

 

Intriguing!

[+Nezgar]

Here we go:

https://youtu.be/iAJxSe1WLco

 

I'll just add that both the Tandon & WST drives I tried this ROM in work perfectly fine with a Mini-Speedy and it's faster stepping rate.

Edited February 8, 2018 by Nezgar

[_The Doctor__]

Try adjusting drive rpm speed,

after that delve into it and...

also, see if it is designed with smaller degree of turn on the stepper in mind which... = more steps to get to a standard track, or even more tracks per disk..

unless it's been damaged or incorrectly read. It may just be one the other or all of the above.

Edited February 8, 2018 by _The Doctor__

[+Nezgar]

RPM's are good. They work fine with Happy or Mini-Speedy.

 

I would think that if the ROM was incorrectly read it wouldn't POST at all. How thorough is the POST checksum? (if there is one done)

 

Hmmm! Looking more closely at the stepper used on the two mech's I tested, both are probably the same actually. Tandon mech stepper white label "Northland - A Scott Fetzer Company" Mt Juliette Tennessee, and the WST has a "Novacom - A Scott Fetzer Company" in same font, probably same stepper company renamed. Both say 1.8 Deg/Step

 

Looking at 2 other Tandon drives I didn't test this ROM in yet, their stepper is a blue label "Japan Server Motors (s) Pte Ltd. Singapore". also says 1.8Deg/Step. These one's are jumpered for mask ROM not EPROM so can't quickly test it on there right now. Maybe this other stepper type will work with it. Will try one of those tomorrow.

Edited February 8, 2018 by Nezgar

[+kheller2]

Stepper units for WST/Tandon: http://atariage.com/forums/topic/156462-1050-roms/?p=3581946

ijor stated here http://atariage.com/forums/topic/156462-1050-roms/?p=3581342the differences in step

[+Nezgar]

THanks kheller2, i recall coming across that thread about the faster stepping rate now!

 

So much fussing with 1050's this evening... soldering to re-jumper this drive to EPROM mode, replaced crappy 6810 RAM socket with a machine socket... and couldn't get this USD EPROM to POST at all in that drive (power light, no action). This board still worked fine with a Happy or Speedy board... Gotta play test that one a bit more, maybe the ROM socket is bad, but I need to burn some stock 1050 OS's for further testing.

 

Anywho.. I swapped the mech with the "Japan Server Motors" stepper into the drive with the working board, and stepping is still glitched with this USDoubler ROM. Maybe there's yet another stepper motor that is compatible.

 

Not sure if this plays a factor, but the working 1050 PCB has a WDC2797 controller (the one with the pin clipped for double sided), non-working pcb is a WDC2793A.... Hmm.. but the first drive i tested yesterday had a 2793 as well. probably not be a factor in this case.

[+Nezgar]

http://atariage.com/forums/topic/156462-1050-roms/?p=3581946<-- Hmm that post shows a WST drive with a "Sankyo Seiki MSHF200B71 (Japan)" stepper, different that my WST - maybe that is the only one that works with this ROM. and maybe Stock 1050 OS Rev L which supposedly uses faster stepping rate, which maybe was the inspiration for an updated USD Rom. Or this was a hack by a 3rd party to incorporate the faster stepping they saw in 1050 Rev L...

 

The three steppers I've come across in my 1050's so far that are not compatible...

Tandon mech with JSM Stepper:

 

Tandon mech with 'Northland' Stepper:

 

WST mech with 'Novacom' Stepper:

 

Cheers

Edited February 9, 2018 by Nezgar

[_The Doctor__]

hmmm I wonder how the ohms per step is interpreted by the firmware.. 60 vs 33 almost double the value. Close to double or half depending which way your going..if your actually using that to sense...

Edited February 9, 2018 by _The Doctor__

[1050]

My take on it is no interpretation allowed, one way

commandments like a boss gives. It either gets done

or you get your paycheck somewhere else.

 

Magnetic strength is a function of ampere/turns, so

60 ohm winding has twice as many windings to make up

for half the current flowing thru it and that equals

the same power used and the same torque output as

the 30 ohm motor. They can do this by using smaller

wire of appropriate size. Not a doubling of gauge

thing but halving of circular mil thing which is too

often confused for millimeter instead of decadenal

area measurement based on SQUARE .001 (thousandths)

of an inch instead. So one circular mil is one square

thousandths of an inch - it can not then measure

.001 since pies are squared don't you know. Cross

sectional area measurement term.

 

The interwebs is completely full of garbage on the

issue and term of circular mil because even the

teachers of millennials didn't know this stuff.

They are quite convinced it has something to do with

millimeters instead of square thousandths of an inch

of a cross section of wire. Direct measurement can not

be done with circular mils, it has to be calculated.

 

It's best to use the full term circular mil and only

cheat between colleagues when shorthanding the term

into mils alone and never use two 'L's either. Already

too much confusion around the term circular mil, but

it has it's purpose in direct comparison to ampacity.

 

As in (4) 3 inch pipes can carry the same amount of

water as a single 6 inch pipe can. But 3 circular mil

wire will only carry half what a 6 circular mil

wire can. No way around the complicated maths to get to

actual dimensions and very limited field of work where

it applies as well means that a very limited few get

trained on the job as it were. Wire gauge charts

showing circular mils all but disappeared too.

 

Not knowing what it were just another low point in

the 'apex' of the information age.

[+Nezgar]

Burned the WST 1050 ROM from this post http://atariage.com/forums/topic/156462-1050-roms/?p=3580891and tested it on my WST 1050, and it works in that drive, with a faster than usual step rate. Faster, but not quite as fast as the Speedy. Interesting to see the WST rom in action in this drive, this drive's had a Happy in it forever, which uses a slower/normal 1050 step rate, and I've never seen a native 1050 seek faster like this that I can remember!

 

The WST ROM powers up in two other Tandon 1050's I tried, but errors reading disks. It just does a track 0/1 step forward/back error loop when trying to boot.. It will however smoothly seek back to track 0 on door close if its been manually moved up.

 

So confirming my drive works with the native WST ROM seems to rule out that that stepping code is the same used in this US Doubler dump. Dunno man, 'tis a mystery. I'm out of ideas unless there's some other mech/stepper that might work, but if that's the case why would ICD release a ROM with such limited drive support?

Edited February 11, 2018 by Nezgar

[DavidMil]

I'm not sure that this EPROM was ever released for sale or not. Some of the 'stuff' that I acquired over the years was experimental and pre-release

'stuff'. Like this 1050 drive that they put the voltage regulators in the middle of the circuit board and couldn't get them to a heatsink. So they moved

the VRegs and ran wires to them from the circuit board. (I'm not sure how good of an idea it is to put a regulator in upside down.) Also this board

would not power up as it was made because Q6 needs to be isolated from the aluminum ground (which it wasn't when I got it). But I fixed.

So I can't say for sure that this chip was or wasn't ever released. It has no markings on the black aluminum window cover. Sorry for not making that

clear at the start. Also sitting in the attic for 35 years in 120+ degree heat for months at a time may have degraded the info on the chip. But some

very interesting information has come from this.

 

Thank you!

David Milsop

Edited February 11, 2018 by DavidMil

[_The Doctor__]

Nice, thanks for posting those pictures. although, the separator should have been there and plastic isolater, with the regulator mounted sideways. Wonder who assembled that one?

Edited February 11, 2018 by _The Doctor__

[+Nezgar]

Sorry I shouldn't have assumed 'released' ! But really makes you wonder what the story behind that ROM was, or if it was incomplete 'under development'. The changes compared to the well known US Doubler version would seem to indicate its more than just a quick hack.

 

That 1050 board looks like maybe they originally thought the heatsink would be rotated around 180 degrees, the 'wall in more the middle of the the drive. EPROM OS also fits with it being an early/prototype board. Can you read any Rev markings on the label?

[_The Doctor__]

Nice theory but no, the heat sink was not to be in the middle of the drive.

[DavidMil]

Can you read any Rev markings on the label?

 

Here are a couple of other pictures of the drive. If you blow up the picture with the EPROM you can see that it says ' 30 P ' sideways. I'm not sure if that

could have been a quality control stamp, but I cant imagine putting a quality control stamp where a rev level marking should be. Also you can see that they

added a lot of missing traces under the board in one of the pictures. One other pic I included was the back of the heat sink. Anyone know the significance

of what that might mean? One way it says " ISNOW", but if you flip it upside down it says, "MONSI". Maybe a name?

 

David

[+DrVenkman]

 

Here are a couple of other pictures of the drive. If you blow up the picture with the EPROM you can see that it says ' 30 P ' sideways. I'm not sure if that

could have been a quality control stamp, but I cant imagine putting a quality control stamp where a rev level marking should be. Also you can see that they

added a lot of missing traces under the board in one of the pictures. One other pic I included was the back of the heat sink. Anyone know the significance

of what that might mean? One way it says " ISNOW", but if you flip it upside down it says, "MONSI". Maybe a name?

 

David

 

One of my 1050's has the same kind of tracing like that between the SIO ports:

 

[+Nezgar]

Interesting 'HCD' stamped on the RIOT and 6507. (Home Computer Division) Curious to compare against known ROM's if you've dumped this EPROM?

[DavidMil]

Interesting 'HCD' stamped on the RIOT and 6507. (Home Computer Division) Curious to compare against known ROM's if you've dumped this EPROM?

 

I'll dump it tonight but I may not get it posted till tomorrow morning. What is the significance of HCD?

 

David

[DavidMil]

I was just looking at the drive again and the HCD on those two chips is NOT visible to the naked eye. The pictures are a couple of years old,

so I'm going to take another set of pics to see if they still exist or have I inadvertently removed the HCD when cleaning the board up.

 

David