View Full Version : Persci 299 with unknown Persci dual S-100 cards?

June 24th, 2015, 04:55 PM
I posted this on the cc-talk list but I thought I'd try here too.

I recently acquired a Persci 2142 dual disk drive with two S-100 controller
cards. The 2142 is a Persci slim-line case that fits the internal Persci
299 drives but also included were to Persci S-100 cards. The only thing
that makes sense is that one or both of these are the Persci 1170
controller card (set) but I have not been able to find a picture of such a
card anywhere. There is an 1170 card picture at the Computer History
Museum but it suspiciously looks like a Vector S-100 prototype board with
components on it (and not the right amount compare to my cards). That page
is here: http://www.computerhistory.org/collections/catalog/102712583

I have pictures in my latest post of the front and back of both cards along
with the Persci 299 drive mechanism and the complete 2142 unit. If anyone
knows what a Persci 1170 controller looks like, I'd love to know if that's
what I have. Is it both cards? I am assuming so because there's a
marketing brochure out there with a description of the 1170 controller and
the Z80 CPU, as described, is on the second card (not the main card) as is
the memory.

Pictures of what I have are here:

I can try to read the EPROMS on the second board (they are B2716s) but the
first board has a 2708 and I've nothing that will read it. Maybe that will
give a clue? I would assume that's where Persci DOS is?

I will be taking the 299 drive mechanism apart and refurbishing this drive
as I did the Persci 270 in my Processor Technology Helios II (big thanks to
Martin Eberhard for his awesome guide and his help!). Hopefully it's close
enough to the 299 that the guide will still be useful. I have yet to check
if the glass scale is intact in this drive or all of this will be for
nothing. I'll do that when I take it apart. Should be a fun project.

If you have any info, please let me know. It would be much appreciated.

June 24th, 2015, 06:05 PM
A system I bought a few years ago came with the same drive. It is still on my todo list, and no where near the top. I will try and take a look at what controllers are in that system. I can't remember if I have the documentation for the drive or not. too much to do and not enough time, once I retire next year I hope to get more done...


June 25th, 2015, 02:36 AM
Funny you should mention this type of drive case. I have one with a 277 drive inside and no controller cards. I just finished re-jumpering it to be helios compatible. Fixed a problem in the power supply and on the lamp board. I should be starting Martin's alignment process later today, though I have pretty much changed every cap and not just the 24V ones. I do expect I might have some bad chips since the -5V was blown on the supply. This is what you would call not a novice project.

I have a spare set of controllers so this will be my Helios II compatible backup since Martin has turned me into a PTDos junkie....

The bearing seem ok for now, so as a winter/fall project I'll repack them since that is one of those tasks that can take a few hours and you can work the grease in while watching TV. He mentioned to me yesterday that you must do the spindle bearing at some point before it destroys itself since there are no replacements available and they all will need it.


June 26th, 2015, 03:18 AM
Thanks for the posts guys.

Kipp, if you can dig up the documentation, I would sincerely appreciate it.

Corey, good luck on the restoration. I haven't yet tried to power it on but will check Martin's guide to see if the boards are similar for the 24v caps, at least. I will also disconnect the drive and check the power supply. Since you're using the same case with the 277, at least I know the power is the same so that's very useful.

Last night I was able to read the EPROMs on the second of the two Persci cards and embedded in the code was the string "ERSCI 1170 V F.2-5". I'm strongly suspecting it's proof that both cards make up a PerSci 1170 controller :) I have the four 2716 EPROMS dumped in the files area of my site at http://vintagecomputer.ca/files-area/ . If someone would like to disassemble them, I'd love to find out more. If there is a tool I can use, please let me know. I was not able to read the 2708 on the first card at this point.

There is no information on the 1170 controller boards, unfortunately, other than the marketing brochure. I'd just like to know if I can jump to an address to access the Persci DOS or if some sort of boot disk is required (that I don't have). It appears to be an uncommon drive so any information at all would be much appreciated.

June 27th, 2015, 03:52 PM
All my documents are for the 277. They came with a cromemco system, so the controller was cromemco as well.

June 27th, 2015, 05:52 PM
Thanks for checking Kipp. I was very hopeful but I appreciate it anyway, even if it wasn't the right docs. The search continues...

June 28th, 2015, 02:44 PM
I started to look over the drive. It looks like it's in good shape but there was a plastic bracket that needed repair. The drive powered up with no issues. I installed the two controller boards into one of my S-100 machines and immediately blew a tantalum capacitor on the first controller board.


I'm really not sure how to read the markings. If someone can tell me what this is, I am guessing it's 1uF @16V but if somone can confirm, it looks like the ones in the picture below:


Thanks in advance.