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mrpi64
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My new board (With better pictures)

Tue Jun 24, 2014 12:17 pm

I bought this off eBay - it's really cool, I have put up some newer pictures:
https://drive.google.com/folderview?id= ... sp=sharing
Last edited by mrpi64 on Mon Jul 07, 2014 7:25 am, edited 2 times in total.
I'm happy to help.
https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=51794 - List of games that work on the Pi.

drgeoff
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Re: My new board

Tue Jun 24, 2014 6:10 pm

In the absence of further info, the AT&T chip would make my first guess be that it is some kind of telco equipment.

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mahjongg
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Re: My new board

Tue Jun 24, 2014 7:26 pm

Its not a non standard size ISA card as the card edge connector top left is 30 pins, and ISA is 31
It also does not resemble a VMEbus card.

wikipedia lists some other bus card systems https://en.wikipedia.org/wiki/Bus_%28computing%29 but on first sight nothing seems to fit.

Could be a propriety bus system, indeed probably for a communication system.

Card edge connectors seem for the busbar backbone, pin header connectors are probably for I/O.

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mrpi64
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Re: My new board

Wed Jun 25, 2014 7:23 am

The eBay ad said that it was unusual.
I'm happy to help.
https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=51794 - List of games that work on the Pi.

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mrpi64
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Re: My new board

Wed Jun 25, 2014 7:26 am

The AT&T chip is a "Field-Programmable Gate Array".
I'm happy to help.
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mrpi64
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Re: My new board

Wed Jun 25, 2014 7:26 am

And it seems such a shame to destroy it.
I'm happy to help.
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MrEngman
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Re: My new board

Wed Jun 25, 2014 11:10 am

It looks really interesting.

I'm guessing that the 50 way may be SCSI and the two 34 ways may be floppy disk interfaces. The 40 pin chips next to them may give a clue. Just can't read the chip types off your picture.

I looks like it's also using a load of PLD's, all those 20/24 pin chips with labels on them.


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drgeoff
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Re: My new board

Wed Jun 25, 2014 2:08 pm

mrpi64 wrote:The AT&T chip is a "Field-Programmable Gate Array".
I'm not aware* that AT&T ever made FPGAs so if the chip really is a FPGA I'd surmise that the logo is on it because it is 'programmed' to perform some logic that AT&T required. Much less chance of it being part of a 'computer' than telco switching or transmission equipment.

(I would expect some clues as to the original maker of the 'virgin' FPGA to be on the package.)

* does not mean they do/did not - I'm not aware of everything. :)

mjtessmer
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Re: My new board

Thu Jun 26, 2014 12:38 am

It fits in a Intel Multibus card slot. The two blue connectors on the
card are iSBX slots.

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mrpi64
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Re: My new board

Thu Jun 26, 2014 12:46 pm

Thanks, I will check that out.
I'm happy to help.
https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=51794 - List of games that work on the Pi.

BMS Doug
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Re: My new board

Thu Jun 26, 2014 12:50 pm

drgeoff wrote:
mrpi64 wrote:The AT&T chip is a "Field-Programmable Gate Array".
I'm not aware* that AT&T ever made FPGAs so if the chip really is a FPGA I'd surmise that the logo is on it because it is 'programmed' to perform some logic that AT&T required. Much less chance of it being part of a 'computer' than telco switching or transmission equipment.

(I would expect some clues as to the original maker of the 'virgin' FPGA to be on the package.)

* does not mean they do/did not - I'm not aware of everything. :)
Google says they did, in 1993 they came out with the ORCA architecture:
AT&T's ORCA (Optimized Reconfigurable Cell Array) architecture extends FPGA applicability into a larger domain than is possible with today's parts, including datapath intensive designs such as memory controllers, signal processing parts, and telecommunication interfaces. Key to the suitability of the ORCA for these jobs is the fact that each of its basic blocks is capable of processing four bits. So, for example, a 16 bit adder requires exactly 4 blocks, not 9 or 16 as in other architectures. Yet the total complexity of each block is comparable to other current parts, thus yielding a significant improvement in functional density.
Doug.
Building Management Systems Engineer.

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mrpi64
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Re: My new board

Thu Jun 26, 2014 12:58 pm

But what board is it? I see no manufacturer name. It is "Assm 01", which may be lucky, and it is made in the USA. It may be a prototype, as there are 2 wires which have been hand soldered underneath the board (maybe they were missed out i the PCB?), and 2 of the resistor networks have been removed and replaced underneath with surface-mount resistors.
I'm happy to help.
https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=51794 - List of games that work on the Pi.

Ravenous
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Re: My new board

Thu Jun 26, 2014 1:09 pm

Well you could start by looking at all of the linked pictures here (just a guess):
http://www.classiccmp.org/hp/multibus/multibus.html

If there is any sort of printed text on the board itself, anywhere, then start googling things and spend a few hours on it at least...

As this apparently became the standard IEEE-796 bus, there are probably lots of purpose-made computers around that period (70s-80s?) that used the overall shape and bus arrangements.

My guess is someone had an old Apollo or some other nostalgic 80s computer, has tried to repair it and eventually gave up (or died) and it got broken up into parts.

Well spotted by mjtessmer by the way!

drgeoff
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Re: My new board

Thu Jun 26, 2014 4:12 pm

Some silk-screened text looks like "Tekelec" at the left hand edge towards the front. There is also a date that I cannot make out.

http://en.wikipedia.org/wiki/Tekelec

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mrpi64
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Re: My new board

Mon Jun 30, 2014 7:40 am

Yeah, that's tekelec. The board has a direct CMOS controller (grey square thing, near processor), floppy disk controller (middle of the 3 chips in a row in the corner), serial controller (chip closest to the edge of the 3 in the corner), an enhanced SCSI-bus interface controller, e.t.c.
Is it worth keeping, or should I take it apart and use the parts off it?
I'm happy to help.
https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=51794 - List of games that work on the Pi.

Ravenous
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Re: My new board

Mon Jun 30, 2014 12:37 pm

I hate to ask a really dumb question, but why did you buy this thing? I suppose if it was cheap that would be OK...

Unless you can find someone who's got the same board running and knows the software it needs (which is possible I suppose) then it might be useless I'm afraid.

If you can't find anyone who knows enough about it there might be some of ye olde standard logic chips on there you could pull and reuse...

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mrpi64
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Re: My new board

Mon Jun 30, 2014 12:49 pm

Yes, it was cheap, and I can re-use all of the parts on it.
P.S: The little row of thin, grey-ish chips that look like resistor networks (in the middle of the left side of the board) are actually Dynamic RAM.
I'm happy to help.
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klricks
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Re: My new board

Mon Jun 30, 2014 1:20 pm

mrpi64 wrote:Yes, it was cheap, and I can re-use all of the parts on it.
P.S: The little row of thin, grey-ish chips that look like resistor networks (in the middle of the left side of the board) are actually Dynamic RAM.
Even if you can remove any of the components without damaging them, I don't think you could reuse anything on that board for any useful purpose. I do see a 'berg' jumper you can reuse.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Buster w/ Desktop OS.

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mrpi64
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Re: My new board

Tue Jul 01, 2014 7:16 am

Sorry, if I didn't make it clear - it's an idea for the future, not for just now.
I'm happy to help.
https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=51794 - List of games that work on the Pi.

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mrpi64
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Re: My new board

Tue Jul 01, 2014 7:21 am

There are 4 jumpers, a PLCC FPGA in a socket, a MC68020 PQFP n a socket, an EPROM (not pictured), and 3 other chips or some kind, all in some kind of socket. Those are easily re-usable (CPU - not so much). I have some better pictures, I will try to put them up asap.
Connectors are all reusable - Probably the resistor networks. I plan to de-solder all of the other chips by attaching a removable heatsink (with a semi-sticky pad, or similar), so that they don't get "burnt-out", or harmfully damaged. And, if the plastic connectors don't melt, then there is a much smaller chance of damaging the chips.
I'm happy to help.
https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=51794 - List of games that work on the Pi.

Ravenous
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Re: My new board

Tue Jul 01, 2014 7:27 am

Heatsinks on the chips will defintely not protect them from the soldering iron. Just warning you. (It'd be a real nuisance if some time in the future you're recycling some of these, and the circuit doesn't work at first, and you can't pin down why.)

There are old school techniques for getting chips out of boards without damage - I'm not an expert but I hope some of the old technicians on this forum will chip in with the proper ways.

(I once worked with a guy whose exercise on his technicians course was to desolder a 40-pin CPU, put it back in and prove it all still worked. That's typical apparently.)

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mrpi64
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Re: My new board

Tue Jul 01, 2014 7:40 am

Maybe something on the pins themselves, then? I'll check YouTube.
I'm happy to help.
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drgeoff
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Re: My new board

Tue Jul 01, 2014 8:50 am

When you want to remove a proven faulty DIL chip the best way is to use small sidecutters to cut through all the legs. The remains of the legs can then be desoldered one at a time with no damage to the PCB.

That method is not suitable if you want to re-use the chip. There are custom soldering iron bits the size and shape of the chip pinout which enable melting of all the joints at the same time. That does not work if there are SMDs on the underside of the board inside the chip footprint, but that is not so common.

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mrpi64
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Re: My new board

Tue Jul 01, 2014 10:08 am

What about a tiny 0.12mm needle-point soldering iron tip - that would give it enough heat to melt the solder, but not so much that it spreads to the chip and burns it out. Right?
I'm happy to help.
https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=51794 - List of games that work on the Pi.

MrEngman
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Re: My new board

Tue Jul 01, 2014 10:23 am

Hre's a few ideas for desoldering http://en.wikipedia.org/wiki/Desoldering

I have used a solder sucker often in the past to unsolder DIL devices without damaging them. Solder wick is also useful.


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