Sparkoids

I can confirm this mod works perfectly on a PAL Rev D Colecovision board. Since I have the VGA F-18A mod I had to put. an extra socket on the video processor to clear the raised RAM in it's sockets

It won't be because Matthew is (I presume) a 60Hz PSU..

The 10uf cap does help make the video output reliable in that it boots to the VGA screen every time instead of it being hit and miss. It is the actual output once Matthew's board is running when you select and try to play the game. The issue is in the Colecovision itself....

OK if it's not the BIOS then is it the 50Hz output for PAL / SECAM TV signal? Both run at 50Hz instead of 60Hz. At some point the signal surely has to be buffered and dumped to the screen (assuming the motherboard crystals are the same). Just a thought....

Ok the BIOS is removed. (Kapton tape around device, preheated the board then removed it with a selective wave solder machine - fitted socket, tested and the BIOS still works). Does anyone have an actual PAL dump of the BIOS for me to check please? My programmer can't read the TMS4764 or NEC D2364 device :-{ Adaptor to follow tomorrow or Wednesday. Thanks for the help Alex_79....

Hi guys, I have tried two Coleco boards now to try and get the F18A VGA adaptor working to no avail. It seems that unfortunately the adaptor doesn't work on European Colecovisions. So I am trying to swap the PAL bios out of the unit for a "No Delay" version which someone on this fine forum said would help. However after getting the eproms ordered it seems the 27C64 is a 28 pin device and I just assumed the chip on the board was the same but it isn't unfortunately :-{ Worse I cannot find a data sheet for the 24 pin TMS4764NL prom anywhere. Has anyone got a data sheet for the device please so I can check the pinout and has anyone actually done a BIOS swap on a PAL Colecovision? Here's hoping and thanks in advance... James :-}

Hi Towmater. What makes you think the bios would make a difference on a PAL machine? Without any evidence at all I can only conclude that it must be the BIOS since there is no other difference in the machines except the PAL ones run at 50 not 60Hz. I am quite prepared to give the BIOS swap a shot I'm that desperate!!

I am in the same position as omf here and can confirm that on two different PAL UK Colecovisions (soon to be three when I dig a spare one out I have) do not work correctly with the F-18A but I believe that it is to do with the bios somehow. I have tried the cap mod on both boards to no avail. The board designer and manufacturer (Matthew) is a first class chap and has been very helpful so far. Does anyone know if the F-18A has ever been successfully tested on a PAL Colecovision?

This looks fantastic. Why not use as much surface mount as you can or (preferably) have dual thruhole / smt tracks on the board? It would easily be possible judging but the size of the PCB. I get that you are prototyping which is fine but if the F-18 is due to be possibly directly mounted on your board then it would make a lot of sense. Just a thought. Great work either way!

OK it *has* to be the F-18 I'm afraid - on the games that do play they hang after a certain time but on the RF/AV they are fine :-{ Thanks for all the help anyway....

OK it is the F-18 or something related to it that is causing the issue. Please ignore my previous post re RAM etc. I just removed the F-18 and soldered the RF modulator back to the board (they are separate on PAL versions). I can now run everything from the SD cart perfectly in terrible RF. Nothing hangs and everything runs correctly. Sooooooo... What is the value of the cap at C106 please? Mine is so old and green in colour (which I assume denotes a tant) I can't read the legend off it? Thanks in advance. I have 5v RAM at the ready if required.... This thing is going to work.... :-}

It is still a bit glitchy unfortunately so I will get onto C106 next - that describes exactly what is happening - the black screen bit. I also have an idea that it may be RAM related. If I leave Donkey Kong on the blue selection screen then it worked sometimes and not others depending on how long before I press start. There is also a graphics glitch that occurs in different places on different games - like 4 pixels in a line which are a different colour. Here is the pic of Donkey Kong with the blue "line" in his Kong's head. That is on an original cart. Space Invaders Part 2 still crashes / hangs in the same place everytime leading me to believe a call is being made and the right answer is not getting back OR the 60Hz from the F-18 is referencing the bios re the NTSC/PAL thing. When it crashes the console needs to be power cycled since the reset won't work. Either way things are moving forward and some games (like Burgertime) are fully playable from the Atarimax SD card. I have even emailed Steve at Atarimax to make sure I have the latest drivers for that device as well. I'm going to fix this damn thing if it kills me! Thanks for the help...

Ok the 10 microfarad 50 volt caps arrived and Donkey Kong nows runs correctly!! I am still seeing crash / hang on the Space Invaders Collection running off the Atarimax SD cart but will need to check with the original cart from home. I am sold on this F-18 - the graphics with scanlines are stunning. Despite some of the games not checking for the PAL/NTSC, 50/60Hz flag in the bios I am not convinced running the PAL 50Hz console at 60Hz via the F-18 isn't responsible for the crash so I'm going to blow some eproms with various bioses and see if it's that. The C3 cap worked OK. A CR network change to delay the reset timing I assume but whats with the tant at C106?

Thanks Tursi. I'm going to order the proper cap. The console reset does not work on Donkey Kong on black screen crash - I need to meter every connection form the removed VDU. Thanks for the help all :-}

Thanks both. I think something else is actually wrong. It runs other games only so far as well then hangs. On DK it stops the console's reset button working. I'm running a diagnostic program on an SD cart at the minute to see what it is but I think it is just disturbing the thing after all these years has done something else. Using leaded solder I have checked and reflowed all chips that looked like they had dry joints and metered the graphics socket to each part of the board and no damage there. C3 is a 1uF 50V cap. Out of interest can I put a 100uF 16v cap in? (I know I can fit it I mean will it work) It's just I have some in a bag here and can't remember how caps work value wise! Cheers again...

Put me down for one of these please Todd :-}

The games don't work with the reset button on the console pressed. Actually the F-18 boots instantly; there is a slight delay for the monitor to select the VGA port. I have a feeling it's to do with the BIOS and the 60Hz thing but am not sure. I will take the audio tap off on Friday (maxed at work) and see if the game is running. Thanks for the reply :-}

Hi all, Got an F-18 board off Matthew and socketed the board and fitted it easily to a PAL ColecoVision - it's a great product. However when using certain games, both original and via an Atarimax SD cart, some of them no longer work but do when I put the VDU chip back in. Donkey Kong gets to the blue selection screen then goes black screen. I haven't taken an audio tap yet so can't say if it's running in the background but it requires a reset from the console rather than the cart. Space Invaders (Opcode Games) hangs about a minute or so into the game and does the same both on the original cart and SD cart but that will reset via the SD cart. The question is does anyone know how an NTSC or PAL bios differed on the Coleco please? I ask because the F-18 sets the refresh rate to 60Hz which is great but I wonder if the games are reading some sort of timings which are correct on the original TMS but incorrect on the F-18? If I have to burn a BIOS that's fine but I'd like to know if anyone else has had this problem or can offer any help. tia James :-}

Hi all, Got back from hols today to see two CV Flashbacks delivered from the States - one 60 and one 61 game version. Both PCB's are the same according to the silkscreen on the PCB. We swapped the TSOPs between the two boards to see if they worked and discovered that the 60 game version can run both chips no problem but the 61 game PCB only runs the 61 game chip. The ICs are standard 1Meg by 16 devices (SST 39VF1602 (61 game) and MX 29LV160 (60 game)). The only difference between the parts seems to be that the MX chip can be enabled as either a 1m x 16 OR 2M x 8 device. Does anyone know if there is an enable line that can do this or is it an instruction from the CPU since it seems weird that it wouldn't run. Checksums ar Interestingly the 60 game that only works in it's original board was a pulled part and had been (pretty badly!) drag solder on the board. We cleaned it prior to fitting it. If anyone knows how the chip arrangement is done on that particular part I'd be grateful. I've searched Google to no avail and a friend who would know is unavailable. Tia... James :-}