Re: [N8VEM-S100:5284] Re: Ithaca Intersystems DPS-1 Front Panel

Thank you for a quick looked at your devices related with U7 or IC7.

In fact, Yoda was right about "Diode Array". It was possible Ithaca engineer(s) designed DSP-1 with "Diode Pack" purpose to protect the circuit because it linked with "HEADER". I believe varistor may use for analog circuit but not suitable with digital circuit therefore the engineer(s) are using diode array.

At this time, no one know what kind of diode array that Ithaca used for DSP-1 board to protect from spike or surge when the cable disconnect from "HEADER" from CPU processor board and front panel board by accident or possible loose connection that will cause failure for both boards.

Now, I vaguely remembered one of my friend who own IMSAI 8080 around 34 years ago. His device went down after he replaced the processor board to run Z-80 instead of 8080. He blew both boards and had to replace numerous of components (Integrated circuits) to run the system again. I think IMSAI did not have "Diode Array" in their front panel board.

Therefore, I completely agreed with Yoga and will use Texas Instruments TID126 on my prototype. Meanwhile I will search for exact brand and model component whcih Ithaca used for DSP-1 board.

Also, I view this situation, YES, it must have diode array for DSP-1. The pin to pin between DSP-1 board and TID126 are not compatible and need to re-configuration by other ic socket and wiring properly.

Thanks,
Steven

On Wed, Sep 17, 2014 at 7:04 PM, Kipp Yeakel <kye...@stny.rr.com> wrote:

Looked at both my systems, neither has u7 populated. So, maybe it is unnecessary.
Kipp

Sent from my iPad

On Sep 17, 2014, at 4:47 PM, Steven Feinsmith <steven.f...@gmail.com> wrote:

Hi,

I appreciate so much to hear from you regardless about arriving late.

You have DSP-1 system and you can help me to find out what brand and type for IC7. I can get all IC chips except IC7. I have schematic showed for IC7 was "Diode Pack", no diagram, no IC number. Someone suggested me to try with TID126. I looked datasheet and believe it is similar one. Hopefully, you can fetch your digital camera and make a shot and show exact label of the IC7.

S-100 group developed two great boards, System Monitor Board and FP Mini Board. Right now, I work on System Monitor Board and seek to buy FP Mini Board soon.

I feel it will be great to have third one, Cloned Ithaca InterSystems DSP-1 Front Panel Board. Because it was superb designed during old days as engineer who designed it after learn from Altair and Imsai front panels and then improved before IBM PC system into the market and ceased S-100 system.

It will be nice to bring it back again and S-100 group can work to enhance the circuit schematic and create full 16-bit data bus. I strongly believe Ithaca engineers did work on new front panel with 16-bit data bus but abandoned it completely in early of 1980's.

During old days, I own a brand new Ithaca InterSystems DSP-1 but stolen during moving along with complete Technical Designs Labs equipment. It broke my heart and hard to forget it. Now, I retired and want to rebuild and bring my old days back to finish my goal. I hope the S-100 Group will consider to create next generation DSP-1 Front Panel Board with 16-bit data bus.

Thank you very much,
Steven

On Tuesday, September 16, 2014 7:20:28 PM UTC-4, Kipp Yeakel wrote:
Sorry for arriving late. I have 2 DPS-1's as well as several other Ithaca systems. I also have a fairly complete set of manuals. I currently have one of my DPS-1s running and booting CP/M 2.2. I haven't had time to check out the others. I have a partially built front panel kit that I was building till I got distracted when looking for proper switches. If there is something that I can do to help you out, let me know.
Kipp

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