+---------------------------------------------------------------------------. Title : Cinematronics CPU 16K ROM Upgrade : Version : 1.0 : Date : 28-October-2002 : Author : McClintock (with text shamelessly stolen from Z. Moore) : +---------------------------------------------------------------------------. : +-----------. : Disclaimer \ : +-------------`-------------------------------------------------------------. : REMEMBER, NO WARRANTEES, EXPRESS OR IMPLIED, ARE GIVEN. USE THIS : INFORMATION AT YOUR OWN RISK. I AM NOT RESPONSIBLE FOR ANY DAMAGES : THAT MAY OCCUR TO YOUR PERSON OR PROPERTY. : : : +--------------------------------. : Using Larger EPROMs on your CCPU \ : +----------------------------------`----------------------------------------. : The following text describes the necessary upgrade modifications to a : Cinematronics CPU ("CCPU") to allow the use of 2732 EPROMs in place of : 2716s. This document will also be helpful in documenting the proper : jumpers that should be on all factory-modified CCPUs that used 2732 : EPROMs. : : First, lets review the different Cinematronics CPU Revisions: : : Rev. A: Space Wars (no revision is actually noted on the PCB) : Rev. B: Space Wars; Star Hawk; Rip Off : Rev. H: Rip Off; Star Castle : Rev. K: Rip Off; Star Castle; Armor Attack; Solar Quest; : War of the Worlds; Boxing Bugs; Demon : : Depending on the Revision CCPU you have, your game might have used 9316 : marked PROMs, 2708s, 2716s, 2532s(?) or a ROM expansion board which was : connected to the 1st and 3rd sockets (U7 and R7). Some CCPUs use 2 PROMs : instead of the normal 4 PROM setup. These 4K masked PROMs were : manufactured with the 2K blocks reversed. To fix this, Cinematronics : lifted the 2K address leg of each PROM so that it didn't go in the socket : and jumpered it to the ROM spot to the left which uses an inverted : signal for that line. What a mess! : : Original CCPUs that have been modified for 2732s are marked Revision K : on both the parts and solder side. You will note a multitude of (usually) : blue jumper wires on the back of the PCB. If you have one of these PCBs, : and it doesn't work, check the details below to make sure you aren't : missing a wire or two. : : All the Vectorbeam CPU boards were wave soldered at the factory with only : the 1st and 3rd ROM sockets intact (U7 and R7). The only difference : between the 1st and 3rd sockets and the 2nd and 4th sockets are the : inverted select lines. When you have a PROM masked for you, you can : choose to have the select lines inverted from the normal EPROM usage, : and this is what Vectorbeam did. Most of the Cinematronics masked parts : seemed to have been masked using a normal EPROM select line, and plugged : into sockets 2 and 4. : : When Vectorbeam re-merged with Cinematronics, Cinematronics got a : "shitload" of old Vectorbeam boards. So Cinematronics dilemma was that : they "inherited" a bunch of Vectorbeam boards with sockets only in the : 1st and 3rd position, yet their mask parts were designed for the 2nd : and 4th position. The choice is to solderwick all the plated through : holes to allow the addition of a socket (a pain), or simply to use the : supplied sockets, bending up the selection pin on their masked parts : and solder a jumper to the proper pin on the adjacent socket (much : easier). : : : +--------------------------. : CCPU Modification Details \ : +----------------------------`----------------------------------------------. : Cutting Traces: : -------------- : 1. Cut the trace (or remove the ceramic cap if you are adverse to cutting : traces) which leads to pin 21 of each EPROM (P7, R7, and T7). EPROM U7 : has no ceramic cap on pin 21, so there is nothing to cut or remove. : 2. Cut the trace connecting J10 pin 4 to J12 pin 7. : : Jumper Wires: : ------------ : 3. Connect pin 21 of each EPROM socket(P7, R7, T7, and U7) to J10 pin 5 : 4. Connect J10 pin 1 to I10 pin 10 and I10 pin 11 : 5. Connect J10 pin 4 to I10 pin 8 : 6. Connect J10 pin 8 to J12 pin 7 : 7. Connect J10 pin 8 to I10 pin 5 and I10 pin 4 : 8. Connect J10 pin 9 to J10 pin 12 : 9. Connect J10 pin 10 to J10 pin 13 : 10. Connect J10 pin 11 to I10 pin 6 : : : Now you can place up to four 2732 EPROMs in your CCPU. If you choose to : combine four 2716 ROM images into two 2732 EPROMs, your new program EPROMs : must be placed into locations T7 and P7 (sockets 2 and 4 when counting : from left to right). : : +---------------------------------------------------------------------------: