Vintage Ohio Scientific Computer OSI Challenger II C2 - 8P 6502 1977 Superboard
Item History & Price
| Reference Number: Avaluer:51459503 | Brand: ohio scientific |
| Vintage: Yes | Model: Challenger 2P |
For sale is a circa late 1977 Ohio Scientific C2-8P.
This machine (produced several years before the popular Superboard II and listed in the 1978 OSI catalog), is packaged in a big blue box and features separate boards for each function with an 8-slot backplane allowing expansion. The 8P was intended as a machine for research, educational, or small business use. The original machine (in 1978) shipped with 4K of RAM and sold for $799. This one has been expanded.
T...his Challenger-2 box consists of the following:
Model 580 Backplane (8 slot)
Model 500 CPU (with 4K of memory right on the CPU board) – circa 1977.
Model 540 Video Card (provides composite video output, also comes with parallel keyboard connector)
Model 420 Memory Card (with 32 2102 SRAM chips for an additional 4K of memory)
Model 542 Polled keyboard (connected via a ribbon cable).
The CPU has both the SYNMON monitor and BASIC installed. The SYNMON monitor resides on a 2K 2716 EPROM in the first ROM socket (not a 1702A 256 byte EPROM in one of the three sockets near the CPU - those chips required multiple voltages to work and are completely obsolete). This monitor socket is mapped to 0xF800 to 0xFFFF (in this respect, the board has been upgraded to the same configuration as the 500 rev B board which has a single 2K ROM for the monitor and no 1702A sockets). BASIC resides on two 4K 2732 EPROMs in the second and third ROM sockets (mapped to 0xA000 to 0xAFFF and 0xB000 to 0xBFFF respectively). Jumpers and wires on the board configure the sockets for these devices. The fourth ROM socket is still free for expansion. When powered, random characters appear on the screen then when reset, the familiar "C/W/M ?" prompt appears (although one could swap the EPROM for one used with a disk exclusively to give the "H/D/M ?" prompt in which case BASIC would run from a disk and not from the ROMs).
The CPU board is a very old design (the 500 CPU was the first one offered in a Challenger 2 system and was superceeded quickly by the 502 and 505 boards). It lacks a quartz crystal, instead using two sections of a 74LS123 one-shot chip to generate a high-speed (1MHz) and low-speed (about 500kHz) clock, the latter used to generate WAIT states for slow memory and devices.
Note that the serial port on the 500 CPU (the 6850) is not installed. Located at 0xFC00, it is right in the middle of the 2K monitor EPROM (this is the way the board was configured when I received the unit many year ago). According to the manual, it was done this way so the port can act as the console in a system without a video card (i.e. a serial-only system). Since this system has video, the port is superfluous, however it appears it was used at one point with the 540 card for the cassette port (how, I am unsure, since it is not mapped into memory at the correct address for a cassette port). Logically, then, for the original on-board serial port to work the monitor ROM must be decoded differently (i.e. mapped only to the required area in upper memory, not the entire 2K block). According to documentation of the 500 CPU board, that on-board port can be configured as an RS-232 port or a 20mA TTY port (the interface is not tested).
For cassette operation that 6850 serial port can be relocated to F000 to F001 (the "normal" location for a newer system), or an additional serial port board (like a 550) can be added to the backplane. The 540 board apparently has the Kansas-city standard FSK decoder/encoder chips on it but this was completely untested (since there is not serial port on the system for cassette anyway).
The 420 memory board is also a very old design, using 2102 1K-by-1 bit memory chips. That board could be configured as 4K*12 or 4K*8 (as it is here). It also had provisions (according to the documentation) for an external battery backup.
Additional memory cards and interfaces cards (such as a parallel interface and even a 470 floppy controller) can be installed to expand the system.
Tested, the system powers on with random characters on the (composite) video monitor via the "Vid" output. Pressing the reset button (the lit power indicator on the front of the box) brings-up the "C/W/M ?" prompt. "C" selects BASIC cold start. Video is configured for 64-columns.
The 540 video board is the first generation and uses sixteen 2102 memory chips for 2K of video RAM. One of these seems to be "flaky" as sometimes, on reset, "block" characters appear on the lower-half of screen (only a few, but the disappear when scrolled). This was observed on initial boot and seems to go away ... it does not affect the operation of the machine, at least, since it is dedicated video memory. It features a 64-column display (switchable to lower resolution using a POKE in BASIC).
The 542 keyboard (which has circuitry inside) connects to the system via a ribbon cable to a DIP socket on the 540 video board. It will be removed for shipping and must be re-installed before use (see photos).
The configuration is exactly what OSI described in their 1978 catalog for the C2-8P (except with 4K more of RAM) and all of the cards are of the same vintage.
The linear power supply appears to be OK and all voltages check-out (it was tested with all cards removed FIRST to ensure they would not be damaged). It is a Deltron (and looks to be original including the warning sticker on top).
This is a large system (the size and weight of a microwave oven) and so be aware that shipping costs will be somewhat high!
This auction consists of the main blue box with power supply and backplane, three cards (CPU, Video, and RAM), and an external keyboard. No cables are included.
This computer is a piece of history. Due to its age is being sold "as is". Testing was completed as outlined above however not all functions of this system were tested (e.g. the cassette port). It is not guaranteed to be a perfect system. Some faults may be present or may develop during shipping (e.g. occasionally keys become "sticky", sometimes cold solder joints appear on a PC board especially at the connectors to the backplane) ... usually this can be easily repaired but will require use of a soldering iron and some skills at electronics repair (even in the 1970's and 1980's these types of repairs were commonly required on systems such as this). This system is best suited for a collector who has technical skills.
Shipping is by Canada Post tracked parcel. Sender reserves the right to send the item via an alternative carrier (e.g. a courier) but the postal rates quoted by eBay will be honoured (in other words, it may arrive by a carrier other than Canada Post however you will not be charged extra for shipping). Import taxes, fees, and duties are the responsibility of the purchaser.
Due to the weight of this item as well as the complexities of shipping items like this, this specific item ships ONLY to Canada and the continental United States. Due to CoVid and there will likely be delays in shipping.
Please note again: this specific item ships ONLY to Canada and the continental United States. International bids will be cancelled.
This machine (produced several years before the popular Superboard II and listed in the 1978 OSI catalog), is packaged in a big blue box and features separate boards for each function with an 8-slot backplane allowing expansion. The 8P was intended as a machine for research, educational, or small business use. The original machine (in 1978) shipped with 4K of RAM and sold for $799. This one has been expanded.
T...his Challenger-2 box consists of the following:
Model 580 Backplane (8 slot)
Model 500 CPU (with 4K of memory right on the CPU board) – circa 1977.
Model 540 Video Card (provides composite video output, also comes with parallel keyboard connector)
Model 420 Memory Card (with 32 2102 SRAM chips for an additional 4K of memory)
Model 542 Polled keyboard (connected via a ribbon cable).
The CPU has both the SYNMON monitor and BASIC installed. The SYNMON monitor resides on a 2K 2716 EPROM in the first ROM socket (not a 1702A 256 byte EPROM in one of the three sockets near the CPU - those chips required multiple voltages to work and are completely obsolete). This monitor socket is mapped to 0xF800 to 0xFFFF (in this respect, the board has been upgraded to the same configuration as the 500 rev B board which has a single 2K ROM for the monitor and no 1702A sockets). BASIC resides on two 4K 2732 EPROMs in the second and third ROM sockets (mapped to 0xA000 to 0xAFFF and 0xB000 to 0xBFFF respectively). Jumpers and wires on the board configure the sockets for these devices. The fourth ROM socket is still free for expansion. When powered, random characters appear on the screen then when reset, the familiar "C/W/M ?" prompt appears (although one could swap the EPROM for one used with a disk exclusively to give the "H/D/M ?" prompt in which case BASIC would run from a disk and not from the ROMs).
The CPU board is a very old design (the 500 CPU was the first one offered in a Challenger 2 system and was superceeded quickly by the 502 and 505 boards). It lacks a quartz crystal, instead using two sections of a 74LS123 one-shot chip to generate a high-speed (1MHz) and low-speed (about 500kHz) clock, the latter used to generate WAIT states for slow memory and devices.
Note that the serial port on the 500 CPU (the 6850) is not installed. Located at 0xFC00, it is right in the middle of the 2K monitor EPROM (this is the way the board was configured when I received the unit many year ago). According to the manual, it was done this way so the port can act as the console in a system without a video card (i.e. a serial-only system). Since this system has video, the port is superfluous, however it appears it was used at one point with the 540 card for the cassette port (how, I am unsure, since it is not mapped into memory at the correct address for a cassette port). Logically, then, for the original on-board serial port to work the monitor ROM must be decoded differently (i.e. mapped only to the required area in upper memory, not the entire 2K block). According to documentation of the 500 CPU board, that on-board port can be configured as an RS-232 port or a 20mA TTY port (the interface is not tested).
For cassette operation that 6850 serial port can be relocated to F000 to F001 (the "normal" location for a newer system), or an additional serial port board (like a 550) can be added to the backplane. The 540 board apparently has the Kansas-city standard FSK decoder/encoder chips on it but this was completely untested (since there is not serial port on the system for cassette anyway).
The 420 memory board is also a very old design, using 2102 1K-by-1 bit memory chips. That board could be configured as 4K*12 or 4K*8 (as it is here). It also had provisions (according to the documentation) for an external battery backup.
Additional memory cards and interfaces cards (such as a parallel interface and even a 470 floppy controller) can be installed to expand the system.
Tested, the system powers on with random characters on the (composite) video monitor via the "Vid" output. Pressing the reset button (the lit power indicator on the front of the box) brings-up the "C/W/M ?" prompt. "C" selects BASIC cold start. Video is configured for 64-columns.
The 540 video board is the first generation and uses sixteen 2102 memory chips for 2K of video RAM. One of these seems to be "flaky" as sometimes, on reset, "block" characters appear on the lower-half of screen (only a few, but the disappear when scrolled). This was observed on initial boot and seems to go away ... it does not affect the operation of the machine, at least, since it is dedicated video memory. It features a 64-column display (switchable to lower resolution using a POKE in BASIC).
The 542 keyboard (which has circuitry inside) connects to the system via a ribbon cable to a DIP socket on the 540 video board. It will be removed for shipping and must be re-installed before use (see photos).
The configuration is exactly what OSI described in their 1978 catalog for the C2-8P (except with 4K more of RAM) and all of the cards are of the same vintage.
The linear power supply appears to be OK and all voltages check-out (it was tested with all cards removed FIRST to ensure they would not be damaged). It is a Deltron (and looks to be original including the warning sticker on top).
This is a large system (the size and weight of a microwave oven) and so be aware that shipping costs will be somewhat high!
This auction consists of the main blue box with power supply and backplane, three cards (CPU, Video, and RAM), and an external keyboard. No cables are included.
This computer is a piece of history. Due to its age is being sold "as is". Testing was completed as outlined above however not all functions of this system were tested (e.g. the cassette port). It is not guaranteed to be a perfect system. Some faults may be present or may develop during shipping (e.g. occasionally keys become "sticky", sometimes cold solder joints appear on a PC board especially at the connectors to the backplane) ... usually this can be easily repaired but will require use of a soldering iron and some skills at electronics repair (even in the 1970's and 1980's these types of repairs were commonly required on systems such as this). This system is best suited for a collector who has technical skills.
Shipping is by Canada Post tracked parcel. Sender reserves the right to send the item via an alternative carrier (e.g. a courier) but the postal rates quoted by eBay will be honoured (in other words, it may arrive by a carrier other than Canada Post however you will not be charged extra for shipping). Import taxes, fees, and duties are the responsibility of the purchaser.
Due to the weight of this item as well as the complexities of shipping items like this, this specific item ships ONLY to Canada and the continental United States. Due to CoVid and there will likely be delays in shipping.
Please note again: this specific item ships ONLY to Canada and the continental United States. International bids will be cancelled.
