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Thread: The Eagle PC

  1. #1
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    Default The Eagle PC

    The Eagle PC

    Acquired an Eagle PC model PC-2, and once again, like many very early clones, there is little information about them. So here is a look inside.

    Eagle PC - Front.jpg

    The Eagle PC was a follow up product to the more powerful Eagle 1600 computer ( Eagle 1600 info http://www.vcfed.org/forum/showthrea...-1600-computer ). I don't have the exact release date for either, but it seems its release was not too long after the 1600, probably around early 1983. The Eagle Spirit "luggable" (also branded as "Eagle PC") seems to have been released about the same time or perhaps slightly later. I posted an approximate Eagle model list here: http://www.vcfed.org/forum/showthrea...ter-model-list

    While the Eagle 1600 was a more powerful somewhat-IBM compatible 8086 based machine, the Eagle PC boasted better compatibly with IBM.

    Eagle PC - Motherboard.jpg

    The Eagle PC is based around the 8088 CPU. It supports up to 512k of RAM on the motherboard, has two built in serial ports, a built in parallel port, and the "PC-2" model comes with dual half height 360k floppy drives. (The "PC-1" model only came with one drive). There are three ISA slots, but one is taken up by the floppy card, and another is taken up by the video card, leaving only one free.

    From various chip dates, I would guess this machine was manufactured in the first half of 1983.

    Interestingly, the 8088 CPU installed is an early one with the interrupt bug.

    I/O ports:
    This machine has two serial ports and one parallel. The serial ports both use female plugs, which requires a gender changer for most standard PC stuff. The parallel port seems to use the earlier centronix plug, unlike IBM PCs or most clones.

    Eagle PC - Floppy and Power.jpg
    The installed floppy drives are Teac FD-55B-01-U, standard double sided double density half height floppy drives. The floppy controller card is the same as the one used in the Eagle 1600, and it even says "1600" on it. Unlike IBM, this card requires a flat cable. This means one drive must be jumpered as DS0 and the other as DS1, and both motors run at the same time.

    Since these are 360k drives, disks were easily interchangeable with IBM PCs. This was not the case with the Eagle 1600, which used higher capacity quad density 80-track/96TPI drives.

    Eagle PC - CGA Card.jpg

    This Eagle PC came with a CGA compatible video card. I believe monochrome cards were also available. When I tested this card, it seemed very compatible with IBM CGA, including composite color artifacting identical to the early IBM CGA cards.

    The Eagle Color/Graphics Adapter board was advertised as compatible with the 1600, Eagle PC, IBM PC, and most IBM PC Clones.

    When I tested it on a 5150 motherboard, I got full composite color. Oddly when I run it with composite in this Eagle PC I get a weak, poorly synced, monochrome image. I suspect there could be a power issue. RGB works fine, though.

    Eagle PC - Bottom.jpg

    ISA slots:
    The Eagle PC, at least this model, only has only three ISA slots and only one is normally free. It does recognize IBM PC cards such as hard drive controllers. It makes me wonder why they did not put the FDC on the motherboard. But on the plus side, it easily accepts high density floppy controllers.

    Notice that the ISA cards are only accessible after removing a panel from the BOTTOM of the machine. Yes, all the guts are mounted upside-down!

    Eagle PC - Motherboard In Case.jpg

    Which raises an interesting point about assembly/disassembly. To access the motherboard, one must remove the bottom foot/keyboard storage part, then remove the bottom plate on which the floppy drives and power supply are mounted. (see the floppy drive picture).

    Protip: The correct way to remove this bottom mounting plate is remove the ISA cards, unplug the power connector from the motherboard, unplug the connector to the 120 volt socket, unscrew the screws around the edge and one between the floppy drives. Gently lift out and avoid dropping/placing this heavy panel on the bottom case rim to avoid scratching the rim.

    Unfortunately, with the power supply mounted on this section, working on the motherboard becomes a pain in the butt. If you have to keep lifting/dropping the bottom mounting panel, such as when hunting down dead RAM chips, place something soft under the left and right edges.

    Eagle PC - Fan Mount.jpg
    An interesting "feature" of this machine is that it is completely fanless. Although, there is a place inside the case where a fan can be mounted. The quiet, fanless design was actually one of Eagle's selling points.

    Like the 1600, it has a metal door on the side, with a magnetic latch, that covers the ISA card brackets.

    Keyboard:
    The early Eagle PCs and the 1600s came with Eagle's expanded 105-key keyboard. Several bundled applications could make use of the extra keys. Both of these machines can also use any IBM PC/XT compatible keyboard. But oddly, even this updated BIOS defaults to assuming you have a 105 key keyboard. This prevents the keypad arrow keys from working without holding "shift". Running the "keyboard" command provided with the Eagle Computer MS-DOS 2.1 will set things to normal.

    The Eagle PC case features a storage area under the CPU in which you may slide in and store your keyboard.

    The Eagle 105-key keyboard uses capacitive key switches. I still need to replace the foam pads on this one.

    BIOS:

    At some point, this machine was upgraded to a later ~1986 BIOS that presumably increases PC compatibility, but would also be free of any infringing IBM code. According to https://books.google.com/books?id=hy...lus%22&f=false Eagle copied some of IBM's BIOS code and IBM sued, and infringing PCs stopped shipping on March 7 1984.

    The installed BIOS reports itself as "BIOS VERSION 2.812" "Copyright (c) 1986 Wilkinson Software"

    Oddly, when I got it there was a second 2764 EPROM chip stuffed in the second BIOS socket (socket 1103) labeled "E/PC REV-A48 4-6-83 U1103". But the Output Enable pin was intentionally bent, so it did not actually do anything. Apparently, this was one of two original BIOS ROMs, but the 1986 upgrade reduced the size to one ROM, so they left the second one in there.

    The contents of this chip were identical to the second ROM of the Eagle PC Spirit set found on Minuszerodegrees.net. One would reason that this meant both of the original ROMs would have been identical. I tested burning the first Eagle Spirit ROM and replacing the upgraded chip, however the machine would then not boot at all. A bit odd. That could mean the first ROM was not identical, or perhaps something else was upgraded too.

    It is notable that this motherboard has no DIP switches. (Just a few jumpers that I don't know what they mean yet) Everything is either autodetected or hard-coded in to this BIOS. I also tried a generic Pheonix BIOS, but it got confused without the DIP switches.

    There was an Eagle PC Tech Manual on ebay a while back, but it sold for a rather high amount.

    SASI?:
    When the Eagle PC technical manual came up on eBay, one of the photoed pages mentioned the Eagle PC could also use Eagle's SASI card. I tried the SASI card from my 1600, but it did not seem to recognize the card at all. It is possible only the earlier BIOS supported it.

    While there is no room internally for the SASI bridge board or a full height hard drive, Eagle did make external hard drive units and my SASI card has a place to plug in an external unit.

    So it's back to looking for the Eagle 1630 Test and Initialization disk: http://www.vcfed.org/forum/showthrea...-Diskette-quot

    Summary:
    Over all, this seems like a decent proprietary-form PC clone. I'm not sure I'm a fan of the fanless design, and the power supply seems a bit weak. However, it is not really meant to be upgraded or expanded. What is built in does not put off too much heat or use too much power. Its 512k limit is somewhat annoying as much DOS software expects a full 640k.

    Over all, this unit seems perfectly IBM PC software compatible. Everything I threw at it worked well. It would be nice if I could test it with earlier BIOS versions, but the later version is probably generally better.

  2. #2

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    I remember using its predecessor, the Eagle AVL. It was the first micro I ever used way back in 1992. I had used a CP/M-driven AVL Eagle, which was about the same size as the original IBM PC, to sequence 2 dozen Kodak Ektamatic slide projectors to soundtracks. The first Eagle computers were produced by Audio Visual Labs (AVL), a company founded by Chuck Kappenman in New Jersey in the early 1970s to produce proprietary large-format multi-image equipment. Those computer sequenced projectors driven by the Eagle were used to create massive 40 foot long by 20 foot high rear-projection multimedia extravaganzas. These were stunning, heart-stopping Hollywood-class analog multimedia productions for major corporate events, hosting thousands of employees, years before the emergence of mainstream computer-based multimedia as we know it today, became possible.

    Mike

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    A few more things:

    Chuck posted this informative link about early Eagle/AVL products in another thread: http://www.stevenmichelsen.com/AVL/

    I certainly agree those were some interesting devices, and the Eagle PC may be rather boring in comparison. It just happens boring early clones is what I find interesting If you really want to snooze, see my writeup of the Tava PC: http://www.vcfed.org/forum/showthrea...ound-a-Tava-PC

    A few photos experimenting with 8088MPH with the Eagle CGA card. Not bad for a clone card. The Columbia Data Products card always gets the colors way off.
    Eagle CGA 8088MPH 1.jpg

    Eagle CGA 8088MPH 2.jpg

    Eagle CGA 8088MPH 3.jpg

    Eagle PC PC-2 BIOS 2.812 1986 U1101.zip

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    Just a quick comparison to some photos from items listed on eBay:
    Eagle PC Spirit Motherboard - 1.jpg
    Supposedly this is from an Eagle Spirit "lugable". It is a very similar board, but most notably has four ISA slots. It also has an IBM style parallel port connector. It seems to be manufactured sometime later, so it is not impossible later Eagle PC desktop models might have also used this board.

    Eagle PC Spirit Color Graphics Card - 1.jpg
    The Eagle Spirit also uses a similar, but different CGA card. The layout looks the same except it has a plug for internal video, it is much taller, and it won't fit in an Eagle PC desktop.

  5. #5
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    Quote Originally Posted by SomeGuy View Post
    A few photos experimenting with 8088MPH with the Eagle CGA card. Not bad for a clone card.
    Not bad is an understatement -- that's identical to the older-style IBM CGA card we used.
    Offering a bounty for:
    - The software "Overhead Express" (doesn't have to be original, can be a copy)
    - A working Sanyo MBC-775, Olivetti M24, or Logabax 1600
    - Music Construction Set, IBM Music Feature edition (has red sticker on front stating IBM Music Feature)

  6. #6

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    Yep! I think this may be the first clone CGA I see where the artifact colors are dead-on. (The Compaq CGA was good too, but I don't recall if it was 100% accurate or just very close.)
    In fact it's probably the first clone CGA I know of which demonstrably behaves like an early-type IBM CGA, rather than the late-type (post-Portable PC) design.

    BTW: Can you tell if the 8x8 CGA font is also identical to the IBM one, by any chance? The PC-2 BIOS charset (from your ROM dump above, offset 1A6Eh) is completely different from IBM's, so I wonder if the CGA's character generator is consistent with that.
    int10h.org :: :: :: blog

  7. #7
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    Thanks for reminding me. Here are dumps from the Eagle PC CGA card and a CGA card from an Eagle Spirit.

    Eagle PC PC-2 CGA Card Character ROM.zip

    Eagle PC Spirit CGA Card Character ROM.zip

  8. #8

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    Interesting that the second dump contains four different fonts. Are there DIP switches or jumpers on the card to select which one is used?

  9. #9

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    Hah, interesting. The Eagle PC CGA character set is indeed identical to IBM's, but the Spirit one? Someone was being creative.

    I should add these to the hardware fonts archive included with my editor, I guess.

    int10h.org :: :: :: blog

  10. #10
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    You weren't kidding. That font is bit-for-bit identical to one of the fonts in the IBM CGA/MDA ROM.

    It would not surprise me if it also copied the IBM circuitry although it is a different layout.

    My Eagle Spirit CGA card does have jumpers next to the ROM, although I have not tested them. It does look like they would switch fonts. Comparing the chip dates, the Spirit CGA card seems to have been manufactured in very early 1984 (although there is a stamp saying Copyright 1985), while the Eagle PC CGA card was manufactured early or mid 1983. So this Spirit card is a bit later.

    Just for clarity, I don't have an Eagle Spirit, just a CGA card from one I bought a way while back hoping I could use it in my Eagle 1600 until I realized the card is too tall to fit. Although it is almost identical to the one currently on Ebeh, here is a photo of the one I have, :

    My Eagle Spirit CGA Card.jpg

    Funny thing about the Spirit cards - it has a piggybacked logic chip with patch wire, which looks like a last minute change, but the chip positioning is labeled U114B/U114A suggesting that was part of the design.!?

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