bgg Posted December 29, 2008 Share Posted December 29, 2008 Hello. I found my old Colecovision in the garage over the weekend. I have lost the RF switch that you attach to the TV and have been reading about the video mods that people have done on their classic systems. It looks like a lot of people have done the ben heck mod and are happy with it. I've also seen some posts where people recommend adding an additional cpacitator and resistor to the setup. Thanks to all for posting these items! I did some searching and found a post on another site and wanted to know if anybody has tried this one? http://www.colecoworld.com/tools/hardware/CVAVMOD.pdf Any advice you all could provide would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Foster Posted December 30, 2008 Share Posted December 30, 2008 I did the video & bios mod from www.8bitdomain.com. I don't know if these are still available but I'd highly recommend it if they are. Quote Link to comment Share on other sites More sharing options...
bgg Posted December 30, 2008 Author Share Posted December 30, 2008 I did the video & bios mod from www.8bitdomain.com. I don't know if these are still available but I'd highly recommend it if they are. I saw that one, but the site said that there were none available. What does the BIOS update provide? Quote Link to comment Share on other sites More sharing options...
ApolloBoy Posted December 31, 2008 Share Posted December 31, 2008 I did the video & bios mod from www.8bitdomain.com. I don't know if these are still available but I'd highly recommend it if they are. I saw that one, but the site said that there were none available. What does the BIOS update provide? It allows you to skip the "Colecovision Presents" screen when you turn on the system. Quote Link to comment Share on other sites More sharing options...
GonzoCV-1 Posted December 31, 2008 Share Posted December 31, 2008 Hello. I found my old Colecovision in the garage over the weekend. I have lost the RF switch that you attach to the TV and have been reading about the video mods that people have done on their classic systems. It looks like a lot of people have done the ben heck mod and are happy with it. I've also seen some posts where people recommend adding an additional cpacitator and resistor to the setup. Thanks to all for posting these items! I did some searching and found a post on another site and wanted to know if anybody has tried this one? http://www.colecoworld.com/tools/hardware/CVAVMOD.pdf Any advice you all could provide would be greatly appreciated. I'm the guy who advocates for the addition of a 47uF electrolytic capacitor and a 75 ohm resistor on the output of Ben Heck's mod. The reason is that the data sheet for the chip in the RF box daughter board calls for it, simple as that. Quote Link to comment Share on other sites More sharing options...
channelmaniac Posted December 31, 2008 Share Posted December 31, 2008 I did some searching and found a post on another site and wanted to know if anybody has tried this one? http://www.colecoworld.com/tools/hardware/CVAVMOD.pdf I did and liked the results. I designed a small circuit board for it (less than 1" square double sided) and ordered 30 of them. I'll be soldering them up into kits and putting them on my site. RJ Quote Link to comment Share on other sites More sharing options...
bgg Posted January 2, 2009 Author Share Posted January 2, 2009 I did some searching and found a post on another site and wanted to know if anybody has tried this one? http://www.colecoworld.com/tools/hardware/CVAVMOD.pdf I did and liked the results. I designed a small circuit board for it (less than 1" square double sided) and ordered 30 of them. I'll be soldering them up into kits and putting them on my site. RJ Thanks to all for the replies. This has been helpful! I saw the post where you were talking about having some boads etched for the purpose of making the video amplifier. How much will you be selling them for? When would you have one available? Quote Link to comment Share on other sites More sharing options...
channelmaniac Posted January 4, 2009 Share Posted January 4, 2009 Not sure yet. I have to add up the cost of the board, components, wire, and jacks but first I have to test them. I still haven't assembled one to see how it looks. The one I built on a waferboard looked great and I expect this to work fine, but you never know with a video signal. I'll also mod that one with 4516 DRAM (5v only DRAM) for less power draw, cooler running, and more reliable operation and sell it on my website to see if there's a demand for pre-modded systems. Quote Link to comment Share on other sites More sharing options...
bgg Posted January 5, 2009 Author Share Posted January 5, 2009 Not sure yet. I have to add up the cost of the board, components, wire, and jacks but first I have to test them. I still haven't assembled one to see how it looks. The one I built on a waferboard looked great and I expect this to work fine, but you never know with a video signal. I'll also mod that one with 4516 DRAM (5v only DRAM) for less power draw, cooler running, and more reliable operation and sell it on my website to see if there's a demand for pre-modded systems. Thanks for the responses. If you get around to making the boards and figure a price, let me know. I may be interested in purchasing one from you. I may give building my own a try, but I have not souced all the parts as of yet. Do you have an electroics supply website that you recommend? My local Radio Shack does not carry all the required parts. Quote Link to comment Share on other sites More sharing options...
channelmaniac Posted January 7, 2009 Share Posted January 7, 2009 Maybe Mouser or Jameco... but Jameco has a high dollar minimum order. The op-amp used in that circuit isn't too easy to find as it's an old part. I just happen to have a local surplus parts store that had them. I'm digging out from under a LOT of repairs that have arrived in the past week. Once I get some breathing room I'll finsh up this modded one and let you know. Quote Link to comment Share on other sites More sharing options...
bgg Posted January 7, 2009 Author Share Posted January 7, 2009 Maybe Mouser or Jameco... but Jameco has a high dollar minimum order. The op-amp used in that circuit isn't too easy to find as it's an old part. I just happen to have a local surplus parts store that had them. I'm digging out from under a LOT of repairs that have arrived in the past week. Once I get some breathing room I'll finsh up this modded one and let you know. Thanks again for all your help. Good luck with getting caught up! Quote Link to comment Share on other sites More sharing options...
channelmaniac Posted January 10, 2009 Share Posted January 10, 2009 (edited) Here's the pic of the assembled board. I used a single 75 ohm resistor instead of 2 150 ohm ones in parallel. Some tiny coax will hook up the inputs and outputs. I tried to keep the inputs, outputs, and their grounds close together to make it easy to use that kind of tiny coax. The +12v and ground for power are separated on the board but that shouldn't matter any since those are separate wires anyway. I'll try to get it installed tomorrow and post pics of what it looks like when running. I'm thinking that I can use some big pieces of shrink tubing to cover the whole board and just let the wires come out the open end of the tubing. That way it's easy to use some double sided foam tape to stick the board somewhere where it won't bounce around loose in the case. RJ Edited January 10, 2009 by channelmaniac Quote Link to comment Share on other sites More sharing options...
bgg Posted January 10, 2009 Author Share Posted January 10, 2009 That board looks great. I have acquired some of the parts I will need to build my own, but depending on how much you will sell for, I may be more interested in buying one from you. Let me know how the test goes and what you will be selling a board for. I already have the RCA jacks, so I would not need those. Hope your test goes well. Quote Link to comment Share on other sites More sharing options...
channelmaniac Posted January 12, 2009 Share Posted January 12, 2009 (edited) It works, and it works very well! I have 15 kits almost assembled. I need to get the wires cut to size and put in the bags with everything else and they'll be done. I also put together a beta draft of installation instructions. (attached to this post) Once it's finalized I'll convert it to .pdf. Basically, everything needed is in the kit except for tools (of course) and a small piece of double stick tape to hold it in place. Now I just have to add up all the parts and pieces and figure out a price. RJ PS: I already see a grammar error and a glaring omission in the doc. I forgot to put the step in about putting the heat shrink tubing over the board and using a heat gun or lighter to shrink it. Colecovision_Audio_and_Composite_Video_Mod_Installation.doc Edited January 12, 2009 by channelmaniac Quote Link to comment Share on other sites More sharing options...
Prodos8 Posted January 12, 2009 Share Posted January 12, 2009 I did the straight Ben Heck mod on mine and so far I'm satisfied. The little board with the op-amp does look interesting. I mainly did the Ben Heck because I already had the parts for it. Quote Link to comment Share on other sites More sharing options...
Ikrananka Posted January 12, 2009 Share Posted January 12, 2009 It works, and it works very well! I have 15 kits almost assembled. I need to get the wires cut to size and put in the bags with everything else and they'll be done. I also put together a beta draft of installation instructions. (attached to this post) Once it's finalized I'll convert it to .pdf. Basically, everything needed is in the kit except for tools (of course) and a small piece of double stick tape to hold it in place. Now I just have to add up all the parts and pieces and figure out a price. RJ PS: I already see a grammar error and a glaring omission in the doc. I forgot to put the step in about putting the heat shrink tubing over the board and using a heat gun or lighter to shrink it. What type of TV have you been testing the mod on? I'm still looking for a mod that works well on an LCD HD TV. I tried the 8BitDomain mod a while back (http://www.atariage.com/forums/index.php?showtopic=124242) with disappointing results - 8BitDomain put this down to the mod being designed for CRT TVs (unfortunately the HD mods he announced as coming last summer never materialised). I'd certainly be very interested in buying one of your mods if it will work well on a LCD TV. Quote Link to comment Share on other sites More sharing options...
Ikrananka Posted January 12, 2009 Share Posted January 12, 2009 It works, and it works very well! I have 15 kits almost assembled. I need to get the wires cut to size and put in the bags with everything else and they'll be done. I also put together a beta draft of installation instructions. (attached to this post) Once it's finalized I'll convert it to .pdf. Basically, everything needed is in the kit except for tools (of course) and a small piece of double stick tape to hold it in place. Now I just have to add up all the parts and pieces and figure out a price. RJ PS: I already see a grammar error and a glaring omission in the doc. I forgot to put the step in about putting the heat shrink tubing over the board and using a heat gun or lighter to shrink it. Not sure if it's too late to point out, but looking over the audio side of your mod you are taking the audio directly from the CVs audio chip - this means that if you're playing a game using the Exp. Mod #1 then you will not get any sound from your audio jacks. Quote Link to comment Share on other sites More sharing options...
channelmaniac Posted January 12, 2009 Share Posted January 12, 2009 Thanks! I'll have to get one of those mods and see what I can do on the audio part. I tried the mod with a 13" color CRT TV I have in the shop and with my Sony Bravia HD Monitor. RJ Quote Link to comment Share on other sites More sharing options...
channelmaniac Posted January 13, 2009 Share Posted January 13, 2009 (edited) Not sure if it's too late to point out, but looking over the audio side of your mod you are taking the audio directly from the CVs audio chip - this means that if you're playing a game using the Exp. Mod #1 then you will not get any sound from your audio jacks. OK! That should be solved. According to the CV schematics that audio comes in on pin 31 from the expansion connector, goes up to the back of the board near the RF modulator and goes through C88 to meet up with the audio that comes from the SN76489 audio IC. If you take a hobby knife and scrape a bit of the coating from the ground plane between C88 and the RF modulator then you can tap the audio from the leg of C88 closest to the RF modulator and solder the ground wire to the ground plane where you scraped the coating away. I tried it tonight and it works well still from the audio IC but I don't have an expansion module to test it on. Does anyone have one they'd be willing to ship me for testing? I'll reimburse shipping costs and send a kit with it when I return it. RJ Edited January 13, 2009 by channelmaniac Quote Link to comment Share on other sites More sharing options...
BigO Posted January 13, 2009 Share Posted January 13, 2009 I tried it tonight and it works well still from the audio IC but I don't have an expansion module to test it on. Does anyone have one they'd be willing to ship me for testing? I'll reimburse shipping costs and send a kit with it when I return it. RJ PM sent. Quote Link to comment Share on other sites More sharing options...
channelmaniac Posted January 13, 2009 Share Posted January 13, 2009 I tried it tonight and it works well still from the audio IC but I don't have an expansion module to test it on. Does anyone have one they'd be willing to ship me for testing? I'll reimburse shipping costs and send a kit with it when I return it. RJ PM sent. PM replied! Quote Link to comment Share on other sites More sharing options...
channelmaniac Posted January 14, 2009 Share Posted January 14, 2009 (edited) OK... So this Colecovision has been upgraded to 5v only DRAM (MK4516), composite video, dual audio outputs, and a selectable BIOS. I documented the RAM upgrade and BIOS upgrades on my repair log site if anyone is interested. It's no longer finicky about power with the 5v only DRAM in it. A few zip ties to tame the wires and it'll be done. (The big black blob is the video upgrade board. It's enclosed in some heat shrink tubing.) RJ Edited January 14, 2009 by channelmaniac Quote Link to comment Share on other sites More sharing options...
GonzoCV-1 Posted January 17, 2009 Share Posted January 17, 2009 OK... So this Colecovision has been upgraded to 5v only DRAM (MK4516), composite video, dual audio outputs, and a selectable BIOS. I documented the RAM upgrade and BIOS upgrades on my repair log site if anyone is interested. It's no longer finicky about power with the 5v only DRAM in it. A few zip ties to tame the wires and it'll be done. (The big black blob is the video upgrade board. It's enclosed in some heat shrink tubing.) RJ Where do you find the 4516 chips? I've been using 4164 chips -- it seems wasteful to simply not utilize all that extra capacity, but they're cheap and plentiful. Quote Link to comment Share on other sites More sharing options...
bgg Posted January 17, 2009 Author Share Posted January 17, 2009 Channelmaniac, what wattage of resistors did you use for your board? Thanks! Quote Link to comment Share on other sites More sharing options...
unhuman Posted January 17, 2009 Share Posted January 17, 2009 Put me on your list of interested parties! Quote Link to comment Share on other sites More sharing options...
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