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This Assembly Guide is applicable to Version 1.0 (2017-07-21) PCB. At the time of this writing (2017-12-14) I have not tested functionality of the whole board, so these instructions will only cover the Multi ROM and 40/80 switcher features. The composite and RGBI video will be added at a later date.
NOTE: This PCB was designed for the 8032089/90 Revision PET motherboard. Installation on 8032080 requires some tweaking (see below).
For Multi-Edit and 40/80 Switching:
Additional/Future components for Composite video, Video Invert, RGBI:
Please note that the composite section has not been tested, however it is based on a working circuit.
PET Motherboard:
If you have a 40-column board you will need to install the missing RAM and other TTL chips first. These are UB6, UB7, UB8, UC4, UC5. I recommend installing sockets (especially for UB8).
The PET Motherboard 8032089/8032090 has many jumpers to configure the boards memory and video options. There is a main jumper block near the middle with 10 "BA" jumper pairs (marked 1 to 10). These are also marked 40C,80C,40C,80C etc... These jumpers must be removed and replaced by female socket strips (like IC sockets). I suggest machined pin sockets
There are also jumpers marked J1 thru J8. All of these jumpers must be removed and replaced by pin headers.
IC UB8 - We must disconnect PIN1 from the motherboard. You can cut this PIN and solder directly to the PCB and PIN, or you can install a socket (or two) and bend pin 1 out if you prefer.
Multi-EditROM-40/80 PCB:
The PCB is a fairly tight fit, so to ensure proper fit the BA jumpers on the PCB will be soldered with the PCB installed. Install the U6 double-sided header. Now the tricky part... Insert P1-P6 on the PET PCB BA sockets, then carefully insert the PCB onto the PET UD7 socket while guiding P1-P6 into their holes. Make sure the header is centred on the UD7 socket. Once the PCB is mated with the motherboard you can then solder P1-P6. This ensures that the pins will align properly.
Now you can populate the rest of the board.
Flyouts, Jumpers and Switches...oh my:
P7 are flyout wires to the jumpers. P8 is a flyout to UB8 PIN1. Each wire is colour coded, but you can use any colour wire if you want. For my prototype I used colour coded wire with Dupont connectors (female to female) for easy connection or removal.
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Jumpers or Switches:
The board is configurable. You only need to install the options you want. Here are some of the configurations:
Installation on an 8032080 PET motherboard is possible but will require some tweaking. The Multi-EditROM-40/80 PCB was designed for 8032089/090 motherboards which have BA jumpers that are grouped. The PCB is designed to align correctly with these jumpers. On the other hand, the 8032080 board has BA jumpers that are evenly spaced. In order to install the PCB on this motherboard you must raise the entire board up with long pins that can be bent. Since these long pins are usually thicker they may not insert into machined IC sockets, so you may need to use taller headers designed for square pins.
I am planning to install my PCB onto one of these motherboards in the near future, so check back for additional info and pictures.
Here is the Multi-EditROM + 40/80 Column Switcher schematic diagram and PCB:
Page Created: Dec 13/2017. Last updated: Apr 29,2024, 7:00pm EST
Send comments or feedback to Steve Gray(sjgray@rogers.com)