Bill -- I finished examining and cleaning the interior of the drive enclosure this evening. I took note of the jumpers on both drives ‹ interestingly thereMessage 1 of 40 , Nov 16, 2012View SourceBill --I finished examining and cleaning the interior of the drive enclosure this evening. I took note of the jumpers on both drives — interestingly there were many differences between the jumper settings, other than what would be expected (i.e., the drive select and the termination).Here are the jumper settings:Drive0: installed — DS1-T1-X-B-A-ZDrive1: installed — T2-HL-800-DS2-T3-T4-T5-T6-T1-X-B-A-Z (this drive is at the end of the cable)Drive1 also had a drive_ready modification which resulted in pin22 being put on pin4 of the interface connector (jumper R cut; wire from R to pin 4).Given this configuration I'm not entirely sure what system this might have been used in since the drives are set so differently. So, I reset the jumpers per the CompuPro Disk 1 instructions and once I build a cable, I can try it on my IMSAI. Overall the drives look very clean and free from excessive dust.From: B Degnan <billdeg@...>
Reply-To: "email@example.com" <firstname.lastname@example.org>
Date: Wednesday, November 14, 2012 9:46 AM
To: "email@example.com" <firstname.lastname@example.org>
Subject: Re: [midatlanticretro] Lobo floppy drives
Sorry, I mean jumpers on the drives in the enclosure. Here is an
-------- Original Message --------
> From: "B. Degnan" <billdeg@...>a
> Sent: Wednesday, November 14, 2012 9:30 AM
> To: email@example.com
> Subject: Re: [midatlanticretro] Lobo floppy drives
> It might be a pain, but if you have a chance to take a picture of the
> jumpers on the board, I'd be interested to see what you have. I just did
> set of SA800's from an Intel MDS. I expect yours to be completely
... Here s the service manual for the Tandom TM-848, with the schematics in the back: http://bitsavers.trailing-edge.com/pdf/tandon/TM848_service_1982.pdfMessage 40 of 40 , Dec 15 8:13 AMView SourceOn Sat, 15 Dec 2012, joshbensadon wrote:
> --- In firstname.lastname@example.org, Mike Loewen <mloewen@...> wrote:Here's the service manual for the Tandom TM-848, with the schematics in
>> The double-sided drives have a 2S signal on pin 10 of the interface
>> connector to indicate single or double-sided media. The outputs of the
>> respective pulse-shaping ciruitry for each sensor is essentially ORed to
>> form a single Index pulse output.
> Cool, so I can imagine the two sensor signals going to an RS flip flop
> to provide the 2S signal and as you said to an OR gate for the index.
Knock yourself out. :-)
> Hmm, thinking about why, I guess the design was to create a hardwareThe 5.25" drives only had a single index hole aperture.
> error if a user placed a DS disk into a SS drive. As Rich found, the
> lack of index pulses caused a drive not ready. Correct me if I'm wrong,
> but in later 5.25" drives, they did not change the index sensor
> location. Then I suppose the errors created would be software
> I vaguely remember hearing a discussion about how computers switchedI couldn't say. Certainly Woz did a lot in software for his Apple II
> from hardware solutions to software solutions, then back to hardware.
> I just don't know the dates, could this 8" to 5.25" be part of that
disk controller design. Another odd thing about the 8" drivers vs the
5-1/4" drives was that the 8" drives had a write-enable notch, while the
5-1/4: drives had a write-protect notch. Very confusing.
Mike Loewen mloewen@...
Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/