repetto74 Posted May 5, 2021 Share Posted May 5, 2021 Hi Guys, I have built this multicart and used the two bin files to program the two eproms. I can get to the menu but the loading is very erratic. Sometimes the game loaded is not the one selected from menu and other times it crashes. I have I think an issue with a socket where the eprom is not fitting tight but is loose. Can someone let me know what is the value of the pull-up resistor? I put a 10K but not sure this is the correct value to use. Thanks and great project for our beloved Coleco :-)!! Quote Link to comment Share on other sites More sharing options...
+5-11under Posted May 5, 2021 Share Posted May 5, 2021 I haven't really looked at the schematic, but... 10K for the pull-up resistor should be good. It could be a timing issue. Does the selected game work after pressing reset? If not, it still could be a timing issue, with latching of the upper addresses (sorry, would need to investigate further into the schematic, but could try putting small capacitor, maybe a couple hundred picoFarads between timing signals (such as latch, clock) and ground - try one at a time to see if anything helps). Also, are there bypass capacitors on all or at least most of the chips? (from +5V to ground). Quote Link to comment Share on other sites More sharing options...
repetto74 Posted May 6, 2021 Share Posted May 6, 2021 (edited) Hi 5-11, I have built this cart based on the gerber and schematics available for it. There are no bypass capacitors. I have made some extra testings after finally replacing the loose socket with a good one. Basically all games stored in the second eprom are working fine when selected from the menu (the pcb is making use of two M27C801 of 1024k each). If I select a game stored on the first eprom then the Coleco will either crash or load the prompt screen asking to insert a cart and reset will just do nothing. I have checked the first eprom with the programmer and it verified good with the original bin. Here is the schematic of this project. Edited May 6, 2021 by repetto74 Quote Link to comment Share on other sites More sharing options...
+5-11under Posted May 6, 2021 Share Posted May 6, 2021 You could try swapping the two ROM chips. If the problem stays with the board location, there might be an issue with the FET (or possibly circuitry leading to the FET). If the problem moves to the other board location, there might be an issue with the EPROM chip. Quote Link to comment Share on other sites More sharing options...
repetto74 Posted May 6, 2021 Share Posted May 6, 2021 (edited) If I swap the two eproms then the Coleco will load the game available on the first memory bank of the second eprom. As the menu is on the first eprom then i can only load this unique game but indeed it loads. It is maybe irrelevant but worth to mention. The 74LS688DW I have installed is marked 74LS688 and the package was not the good one (smaller then the pad positions on the pcb) but I managed to solder it properly without any shorts. Question is are pinouts different from one package to another? Edited May 6, 2021 by repetto74 Quote Link to comment Share on other sites More sharing options...
repetto74 Posted May 7, 2021 Share Posted May 7, 2021 I have tried to program another 27c801 in position 1 but same issue. I have checked the CE signal on pin 22 and I do have 4.5V when not selected then dropping to 0V when a game from that eprom is selected. Quote Link to comment Share on other sites More sharing options...
+5-11under Posted May 7, 2021 Share Posted May 7, 2021 It might not be switching CE fast enough, or maybe some other timing issue? Does it work if you press reset after selecting the game? - is that the way it's supposed to work anyway? Quote Link to comment Share on other sites More sharing options...
repetto74 Posted May 8, 2021 Share Posted May 8, 2021 The Coleco will usually crash when trying to load a game stored into the first eprom. I'll get a garbled screen like this one enclosed or a freeze on the cart menu. Pressing the reset will either load the same game stored into a certain position on the eprom (DK something) or show up the message to insert a cart into the module. Quote Link to comment Share on other sites More sharing options...
repetto74 Posted August 28, 2021 Share Posted August 28, 2021 Hi, Can someone advise the correct value to use for the resistor? I want to use a 10k resistor by default but maybe if someone can confirm that this value is correct. Quote Link to comment Share on other sites More sharing options...
zx-81 Posted August 29, 2021 Share Posted August 29, 2021 21 hours ago, repetto74 said: Hi, Can someone advise the correct value to use for the resistor? I want to use a 10k resistor by default but maybe if someone can confirm that this value is correct. Hi Repetto74, You need to use a 1k resistor (10k is too high). Zx Quote Link to comment Share on other sites More sharing options...
repetto74 Posted September 17, 2021 Share Posted September 17, 2021 On 8/29/2021 at 8:54 PM, zx-81 said: Hi Repetto74, You need to use a 1k resistor (10k is too high). Zx Hi zx-81, Indeed that was it!! Changed to a 1k pull-up and now the cartridge is working perfectly :-D. Thank you for your support and nice piece of hardware this one ? ! Sorry for the late reply I had many things to sort out in the past months so not so much spare time to dedicate to the 8bit retro computing :-). Cheers, Rick Quote Link to comment Share on other sites More sharing options...
zx-81 Posted September 17, 2021 Share Posted September 17, 2021 @repetto74 glad to see it is working fine. 1 Quote Link to comment Share on other sites More sharing options...
zx-81 Posted April 6, 2023 Share Posted April 6, 2023 Just to let you know that my good friend buzz has provided a new version of the 63in1 with the gerber files : http://buzz.computer.free.fr/index.php?post/2013/01/22/ColecoVision-63-in-1-SMD There is also a small software running under windows to build the two images required for that card : http://buzz.computer.free.fr/index.php?post/2023/03/03/Coleco-ROM-Builder Zx Quote Link to comment Share on other sites More sharing options...
OriginalJohn Posted April 7, 2023 Share Posted April 7, 2023 (edited) On 4/6/2023 at 3:42 PM, zx-81 said: Just to let you know that my good friend buzz has provided a new version of the 63in1 with the gerber files : http://buzz.computer.free.fr/index.php?post/2013/01/22/ColecoVision-63-in-1-SMD There is also a small software running under windows to build the two images required for that card : http://buzz.computer.free.fr/index.php?post/2023/03/03/Coleco-ROM-Builder Zx Hello, This is great news, the added utilities will be very helpful! However, can you ask Buzz to complete the list of parts needed in the readme.txt? There are two components (the resistor, and diode transistor) missing from the list. It would also be helpful if the full part number was added or a saved parts list on digikey or mouser of what exactly is needed. When you search for those part numbers, 5-10 show up and it's hard to know which one is the right one (with different mhz etc). The last time I tried to make this, I could only get it to work by toggling the power switch (game selection didn't work) and a random game would appear. crazy. Edited April 9, 2023 by OriginalJohn Quote Link to comment Share on other sites More sharing options...
Fabriciotm Posted April 8, 2023 Share Posted April 8, 2023 On 4/6/2023 at 4:42 PM, zx-81 said: Just to let you know that my good friend buzz has provided a new version of the 63in1 with the gerber files : http://buzz.computer.free.fr/index.php?post/2013/01/22/ColecoVision-63-in-1-SMD There is also a small software running under windows to build the two images required for that card : http://buzz.computer.free.fr/index.php?post/2023/03/03/Coleco-ROM-Builder Zx Hi Zx, Do you have tried to run Pac-Man from the multicart? In my compilation, Pac-Man always freeze or reset to another game when played. Quote Link to comment Share on other sites More sharing options...
zx-81 Posted April 8, 2023 Share Posted April 8, 2023 @OriginalJohn : For the parts i have used the following : - 74HC574D - 74HC688D - 74HC541D For the resistor 10k Ohms and for the Transistor model i have used is a BS170. Be careful that some of the BS170 may have the drain and the source swapped compared to what is used on the 63in1 PCB. The symptoms are simple in that case : when you select a game from the first bank, it is actually failing as if you had no cartridge inserted (boot logo of colecovision with the message of the missing cartridge). The solution is just to swap the transistor or to solder it on the other side of the card. @Fabriciotm Yes, i know that issue, actually i had to modify manually those roms (Pacman, Popeye, etc ...) to be compatible with the 63in1. In those games, they are accessing the address range 0xffc0 to 0xfffe that we are using for the bank switching and it is messing up everything. What i did is to modify those roms to relocate the portion of data located in that address range and to move it somewhere else in the rom and to modify the binary code accordingly. You can PM me if you need more information. Quote Link to comment Share on other sites More sharing options...
MrDave Posted April 10, 2023 Share Posted April 10, 2023 Do a rom call of the select level blue screen first then the characters will be loaded Quote Link to comment Share on other sites More sharing options...
zx-81 Posted April 13, 2023 Share Posted April 13, 2023 (edited) You should get a menu to select the games at power up. It happens that at power up, a game is started (instead of the menu). I have seen that on adam computer, but not on coleco. If it is always the same game that is started, then you can always put the rom menu at that particular location in the address space of the eeprom. If it is random, then it might be a faulty pcb or bad solder. What i have seen as well is a faulty transistor (or wrongly soldered, with drain and source swapped). In that case it can also provide a wierd boot screen with colecovision letters and random characters below. Edited April 13, 2023 by zx-81 Quote Link to comment Share on other sites More sharing options...
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