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Percom AT88-S1PD - 3.5"drive install? SD-X read FAT12?


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#1 Xebec OFFLINE  

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Posted Tue Aug 8, 2017 4:37 PM

I have a Percom AT88-S1PD (and manual), and wanted some verification on the following: 

 

The Percom hardware can support up to 2 floppy drives internally?  including 3.5"drives?

 

If you put a 3.5" drive inside -- do you end up with 360KB or 720KB of usable space?    and does any standard PC 720KB mechanism work (or old ST floppy)?

 

Finally, can the floppy be formatted to the PC Standard of FAT12 and accessed by SpartaDOS-X ?

 

Thanks...

John 



#2 Larry OFFLINE  

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Posted Wed Aug 9, 2017 6:12 AM

I have a Percom AT88-S1PD (and manual), and wanted some verification on the following: 

 

The Percom hardware can support up to 2 floppy drives internally?  including 3.5"drives?

 

If you put a 3.5" drive inside -- do you end up with 360KB or 720KB of usable space?    and does any standard PC 720KB mechanism work (or old ST floppy)?

 

Finally, can the floppy be formatted to the PC Standard of FAT12 and accessed by SpartaDOS-X ?

 

Thanks...

John 

 

I did test part of this many years ago using my AT-88, which supported DD. I'm not sure about your model number, but I believe it may be single density only. (?)   So that means the most you should  get is 128 X 18 X 80 (tracks)  X 2 (sides) = 360K, if it handles a two-sided drive.  If it is DD, then it should be 720K using 3-1/2" 720K drives using MyDos (or SDX).  And dead-slow in DD since there is no USpd for Percoms.  It's been a really long time since I did this.

 

As far as the Fat-12, I can only say that I used my Percom with my ATR 8000 & CP/M (which has some very different disk formats), but I did not use the Percom controller, since the ATR 8000 handles that.  But how would you even do it?

 

Is your manual different than the regular AT-88 manual?  It is manual #050-1290-001?  I would think a manual specifically for the AT-88 S1PD might be slightly different. (?)

 

Here is a link that might be helpful:

https://www.atarimax...warticle.php?48

 

There was also a good article by Ben Poehland in Atari Classics about the Percoms.

 

And last... be very careful  as the Percom has 110V inside (U.S.) and it can shock you in a heartbeat if you touch the wrong things!

 

-Larry



#3 moonlight_mile OFFLINE  

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Posted Wed Aug 9, 2017 4:36 PM

I have a Percom AT88-S1PD (and manual), and wanted some verification on the following: 
 
The Percom hardware can support up to 2 floppy drives internally?  including 3.5"drives?
 
If you put a 3.5" drive inside -- do you end up with 360KB or 720KB of usable space?    and does any standard PC 720KB mechanism work (or old ST floppy)?
 
Finally, can the floppy be formatted to the PC Standard of FAT12 and accessed by SpartaDOS-X ?
 
Thanks...
John 


Can we get a pic of the actual board. Like to see if you have the dd board.

#4 Xebec OFFLINE  

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Posted Thu Aug 10, 2017 12:21 PM

Can we get a pic of the actual board. Like to see if you have the dd board.

 

http://atariage.com/...4-percom-board/

 

The board is a real PITA to move around, but let me know if you need a pic of any other parts on it to figure out if it's DD



#5 moonlight_mile OFFLINE  

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Posted Thu Aug 10, 2017 1:02 PM

Ah. Yes. Yet another different looking Percom board. Anyway. I can't make out the numbers on that long chip next to the daughter board. I am thinking that is the western digital drive controller chip. Just depends on what number is on it. What numbers are printed on it?

#6 Xebec OFFLINE  

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Posted Thu Aug 10, 2017 1:08 PM

Well my guess is this percom won't work anymore anyway..  the piece of tape fell off the EEPROM chip on the bottom left of the pics, so i'm sure the flash of the picture erased it.. :(

 

Ah. Yes. Yet another different looking Percom board. Anyway. I can't make out the numbers on that long chip next to the daughter board. I am thinking that is the western digital drive controller chip. Just depends on what number is on it. What numbers are printed on it?

 

WDC  FD1795CL-02   (possibly FQ, but pretty sure FD)  



#7 moonlight_mile OFFLINE  

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Posted Thu Aug 10, 2017 1:33 PM

Wow. You got a dd chip.

#8 Xebec OFFLINE  

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Posted Thu Aug 10, 2017 2:17 PM

Wow. You got a dd chip.

 

So double density but limited to single sided?   or could I get 720KB out of a 3.5" ?



#9 moonlight_mile OFFLINE  

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Posted Thu Aug 10, 2017 2:41 PM

The only ds Percom I know of is the rfd44. So yes just single sided. Sadly it will format ds but won't read/write. I was trying to find an rfd44 rom and get one put it in my at88 and see what happens but haven't come across one yet.

And most likely your Percoms voltage regulators took a dump. I had to change mine when I got it. The one literally just fell apart when I removed the board.
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#10 Xebec OFFLINE  

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Posted Thu Aug 10, 2017 3:16 PM

It might work - the spec sheet for this '5' chip claims to have a side select capability..  



#11 moonlight_mile OFFLINE  

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Posted Thu Aug 10, 2017 3:58 PM

Definitely let me know. I have a ss/sd id love to convert.

#12 Xebec OFFLINE  

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Posted Thu Aug 10, 2017 4:40 PM

Well this thing powers on but makes some rough noises..   This was never my drive so I'm not attached to it..  Any idea what this could fetch for sale as-is?  



#13 DavidMil OFFLINE  

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Posted Thu Aug 10, 2017 11:09 PM

Here is two pics of my AT88 board.  I have no idea if the EPROM is good after all these years but the sticker has never been removed.  Does

anyone have any idea what the AC voltage supplying power to this board from the transformer was?  I've replaced all the electrolytic caps and

the three VREGS (two 5V and one 12V). 

 

David

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#14 moonlight_mile OFFLINE  

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Posted Fri Aug 11, 2017 6:22 AM

I thought it was 9v but don't hold me to that. But one thing I notice is you don't have a western digital drive controller chip/board. Did you remove the board that fits in that chip socket?

#15 DavidMil OFFLINE  

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Posted Fri Aug 11, 2017 11:44 AM

I thought it was 9v but don't hold me to that. But one thing I notice is you don't have a western digital drive controller chip/board. Did you remove the board that fits in that chip socket?

 

35 years or so ago, when my Percom unit died, I pulled this board and the drive out of the case and unfortunately threw the case in the garbage.  To be 

honest with you, I don't remember what I had for dinner yesterday.  So I'm sorry to say I have no idea what happened to the chip/board in that socket.

Looking through my collection of 40 pin chips, the only controller chip I have is a WD2793BL-02.  Dated 8333.

 

David



#16 1050 OFFLINE  

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Posted Fri Aug 11, 2017 11:28 PM

Well my guess is this percom won't work anymore anyway..  the piece of tape fell off the EEPROM chip on the bottom left of the pics, so i'm sure the flash of the picture erased it.. :(

They are not overly sensitive to light, they require
UV of intense lumens to achieve erasure. Blowing taps
for it is a bit of drama in my opinion then. Just tape
it back on there and then pretend it didn't happen?

Intel suggests 6 months of office lighting is equal to
2 weeks of daily full sunlight which may or may not
bring about data corruption in some cells. 20 minutes
under the UV lamps of an erasing fixture is the usual
time needed for full erasure.
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#17 DavidMil OFFLINE  

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Posted Sat Aug 12, 2017 12:24 AM

As a rule I will change out all the electrolytic caps when I recondition and old board, as I did with the board in the above pictures.

However, I noticed an error on the silk screen on this board:  Look at Cap C8 in the lower left of the first picture.  Notice the '+'

sign just above the C8.  If I had installed the cap per the silk screen I would have had the positive end going to ground.  In my

experience that is a very fast way to kill a capacitor.  Anyway, if you enlarge the picture you will see that the negative end of the

cap is pointing to the plus sign.

 

DavidMil    



#18 Xebec OFFLINE  

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Posted Sat Aug 12, 2017 6:59 AM

They are not overly sensitive to light, they require
UV of intense lumens to achieve erasure. Blowing taps
for it is a bit of drama in my opinion then. Just tape
it back on there and then pretend it didn't happen?

Intel suggests 6 months of office lighting is equal to
2 weeks of daily full sunlight which may or may not
bring about data corruption in some cells. 20 minutes
under the UV lamps of an erasing fixture is the usual
time needed for full erasure.

 

Good to know - thanks!  

 

My concern was based on things like camera flashes that disable raspberry pi's because of ICs being very light sensitive.  I assumed the old EEPROMs were pretty easy to clear as well.  



#19 Xebec OFFLINE  

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Posted Sat Aug 12, 2017 7:03 AM

Is the main advantage to this drive over a 1050 that you can put a 3.5' drive in and achieve higher capacities?  (plus the printer port on the back)?



#20 DrVenkman ONLINE  

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Posted Sat Aug 12, 2017 7:16 AM

Finally, can the floppy be formatted to the PC Standard of FAT12 and accessed by SpartaDOS-X ?

 

 

So, what do you mean by this question? Because you can already format basically any size floppy for use with SpartaDOS X even on bone-stock Atari hardware, in whatever density the hardware and medium supports.



#21 Xebec OFFLINE  

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Posted Sat Aug 12, 2017 7:18 AM

 

So, what do you mean by this question? Because you can already format basically any size floppy for use with SpartaDOS X even on bone-stock Atari hardware, in whatever density the hardware and medium supports.

 

I was curious if with a Percom upgraded to 3.5" floppy, could you format a floppy that is PC-compatible?  (FAT12) and read that back on SpartaDOS-X?



#22 DrVenkman ONLINE  

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Posted Sat Aug 12, 2017 7:49 AM

 

I was curious if with a Percom upgraded to 3.5" floppy, could you format a floppy that is PC-compatible?  (FAT12) and read that back on SpartaDOS-X?

 

I don't believe so; it looks like the FAT drivers for SDX are read-only. But this is just from a cursory examination of the documentation.

 

I haven't tried it myself; I don't have anything with a physical floppy drive these days except my Atari machines. And to get files back to another device, RespeQt running on my computer or RPi gets everything out onto the LAN if necessary for me. 



#23 Xebec OFFLINE  

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Posted Sat Aug 12, 2017 8:15 AM

 

I don't believe so; it looks like the FAT drivers for SDX are read-only. But this is just from a cursory examination of the documentation.

 

I haven't tried it myself; I don't have anything with a physical floppy drive these days except my Atari machines. And to get files back to another device, RespeQt running on my computer or RPi gets everything out onto the LAN if necessary for me. 

 

I hear ya..  I still have a USB 3.5" for the PC, and of course Amiga and ST floppies..  I have extra mechanisms so I just thought it'd be neat to mess around with an Atari 3.5" drive.. 

 

The SIDE 2 handles everything I really care about though :) 



#24 DrVenkman ONLINE  

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Posted Sat Aug 12, 2017 8:19 AM

 

I hear ya..  I still have a USB 3.5" for the PC, and of course Amiga and ST floppies..  I have extra mechanisms so I just thought it'd be neat to mess around with an Atari 3.5" drive.. 

 

The SIDE 2 handles everything I really care about though :)

 

Oh sure; I get the love of tinkering. I just ordered a Happy repro board from Atarimax last night. I'm gonna park it in one of my 1050's and faff around with floppies again just ... because. :) 



#25 moonlight_mile OFFLINE  

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Posted Sat Aug 12, 2017 8:32 AM

 
I hear ya..  I still have a USB 3.5" for the PC, and of course Amiga and ST floppies..  I have extra mechanisms so I just thought it'd be neat to mess around with an Atari 3.5" drive.. 
 
The SIDE 2 handles everything I really care about though :) 


Can the side2 avoid using sdx? I am looking at one for a bbs and it will not run on sdx but I like the speed I have seen in the demos on YouTube.




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