channelmaniac
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Posts posted by channelmaniac
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What other components use the +12v and -5v components of the power once the DRAM is removed?
I had it in my head that such a mod would permit the use of a 5v only supply.
Hmmm...
Off the top of my head, the A/V kit and the RF Modulator use 12v and the joystick ports uses the -5v.
Also, those voltages are fed to the expansion port so removing them may cause some expansion modules to not work.
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OK,
Indy, your modded system will be shipping out tonight. Sorry, but I was horribly sidetracked by prepping for the MGC.
For everyone else, I'll be posting the full instructions to the Dual BIOS mod and +5v memory mod to my website tonight. The kits are fully assembled and ready to go as soon as I get the SKUs added to the site tonight.
$8.99 for the Dual BIOS kit
$13.99 for the +5v Memory kit
And I have all the remaining A/V kits built. I sold a few at the MGC but the rest of them will be listed on the site tonight.
RJ
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Check for proper +5v on the SRAM chips.
Beyond that, the VIC can give those symptoms with a variety of different bad chips: VIC, CPU, SRAM, 6522 VIA, or Kernal ROM.
Unplug the BASIC ROM and the Character ROM one at a time and power it up without those in. If those are shorted on an output then you'll have those symptoms and the system can boot without them.
Try a cart with it to see if it works. Maybe you have a bad SRAM, Kernal, or BASIC ROM.
Worst case, if you can't figure it out, I can do repairs on it for you. I do flat rate repairs on the old school computers.
RJ
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MGC done, one lab due this week. Look out for shipping confirmation emails.
Hey!
It was great meeting you at the MGC event.
RJ
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Check out the Longhorn Engineer's website. He has pics from about a month ago that he is redesigning the 2600 motherboard to fit in smaller portable. If he can produce these, I will be all over it.
It'd be cool to see one based on a 6502 or other more usable CPU.
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Blown fuse on the backlight. It's possible that opening and closing the case causes the end of the element to come in contact or come close enough to arc over just as happens in any other high voltage application. Fuses are at either end of the backlight. Do be careful of any high voltage discharge, even if the unit is unplugged and has no batteries.
Actually that fuse is a thermal fuse. It opens if the current draw is too high OR if the temperature is too high.
If you solder in a replacement you MUST use some hemostats or Kelly Clamps on the lead between the solder joint and the body of the fuse or the heat from soldering it in will open it up.
Read the fuse carefully to get the temperature rating for the replacement.
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I'll order some capacitors from eBay later today. I'll play it safe by getting all of them, although I'll just try replacing the caps that look bad at first.
I'll let you know if it works.
STOP!
Go to www.mouser.com and order them there.
Get 105 degree caps that physically FIT where they are supposed to go. You don't know about eBay caps and if they are counterfeit or even if they will be the right physical shape to fit. Mouser has links to data sheets for their caps where you can find the sizes of them to make sure they will fit where needed.
As for the rubbery stuff on the one cap, it's probably heat shrink tubing.
Raymond
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Sega Genesis controllers seem to me to be the best source for such cables.
You can make your own and/or buy 9 pin cables, but they almost all have the "ears" or whatever the tabs with screws/holes are called.
Yeah, the molded cables have longer ends on them and the DB9 computer cables don't so they won't fit in the joystick ports on the Master System.
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Anyone have a good source for joystick replacement DB9 cables?
I need ones with more wires than the Atari 2600 ones... They only have 6 wires (up, down, left, right, fire, and ground) where I need 7 to fix some Sega controllers (up, down, left ,right, button 1, button 2, and ground).
Seems all I can find are extension cables for $8 each plus shipping from Canada but they don't even list the # of wires inside.
Thanks!
RJ
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74HC series has a different voltage level for triggering logic level "1" than TTL/LS does. This could cause the circuit the chip is in to not operate properly. 74HCT has the TTL/LS compatible logic levels.
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If any of you modders are interested, I have 4 or 5 Colecos in various states of workability. I think they all function to some degree, I'll have to inventory them and list out the errors.
But would anyone be willing to trade? I'll give you all my Colecos for you to fix up and sell (they go north of $100 on eBay) in return for one spiffy, supernice, modded and functional Coleco.
Any takers?
I PMed you. I could use some CVs to take to the show at the end of March.
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His directions for the video mod were great. Probably too much detail sometimes
But... for those of us who can hold a soldering iron, but can't build a circuit, these are perfect. Not really sure I get the advantage of swapping memory, so perhaps some "marketing" on the cost / benefit would be nice.-H
The original memory runs off of 3 voltages: +5, +12, and -5. The Colecovision has a very finicky power supply switch that doesn't make good contact when it gets dirty. This causes the system to power up in states where it won't run. The power supply is also a common point of failure and the tri-voltage chips run hot.
By putting +5v only DRAM in the system you are removing the power on complexity of the tri-voltage DRAM. This reduces current draw on the +12 and -5v sections of the power supply and they run cooler. The system will power up more reliably without the need for flicking the problem prone power switch back and forth to get it to boot properly.
RJ
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Memory upgrades sound interesting are they the lower power one's I've heard about.
Single voltage ones, yes. No more need for +12 and -5v for the DRAM which will make the unit more reliable by making power switch issues far less noticeable. They will also run cooler.
The kits will come with either 4516 or 4164 DRAM chips depending on inventory levels. Either one will work fine in the CV system. I have to modify a system with a BIOS upgrade and the memory upgrade today or tomorrow to take pics and assemble instructions. Instructions without pics are already up on my repair logs site.
RJ
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Highly recommended!
Thanks for the pr0pz!
I have 11 Colecovision AV kits ready to go... 4 more that are almost done - lacking one or 2 items each... and I started building kits up using the last 25 PC boards I have.
I'll also be building kits over the next week or 2 for the memory replacement (8 chips, 8 sockets, instructions, and maybe some wires) and for a dual BIOS upgrade (BIOS chip, switch, resistor, wires, socket, and instructions.)
I'll be stopping by a local supplier to see what all I can pick up from them before mail ordering the rest of the parts.
The plan is to have a pile of kits long with modified game systems, game systems, carts, arcade boards, SRAMs/DRAMs/EPROMs, and lots of custom chips for MGC.
Raymond
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Just got a note from my supplier... the parts I had on backorder have shipped and I should have another batch of kits done this weekend.
RJ
It was the coax - multimeter showed me there was connectivity, but now, there's not and the audio is working. So I've got a fully working (and beautiful) solution. Thanks for the help! Now, I worry that the rust on that one chip will eventually kill my board. I do have one other (dead) CV board. It's a shame the CV case is almost big enough to hold a spare board.... Alas, it is not.
Thanks for the great solution and the help getting it to work!
-Howie
Thanks Howie!
I try to do the right things. Sometimes it's hard to balance a day job with an old school arcade/gaming/computer repair and parts business, but I give it my best.
As for the chip with the rust on it, it's a simple chip to obtain and replace. When that one finally gives up the ghost, just give me the info off the top of it and I should have it. Until then I wouldn't bother with replacing it. It could last a day, it could last another 20 years, but it's not worth replacing yet.
Raymond
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If I order from Mouser before 3pm I get it the next day. They are in Texas so I am kinda cheating
If I order from Mouser before midnight, I get it the next day.
It's nice living across the Metromess from them!
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I've never gotten a paper cut from a TS1000
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Sounds like you may have a surface mount component that needs to be reflowed.
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It was the coax - multimeter showed me there was connectivity, but now, there's not and the audio is working. So I've got a fully working (and beautiful) solution. Thanks for the help! Now, I worry that the rust on that one chip will eventually kill my board. I do have one other (dead) CV board. It's a shame the CV case is almost big enough to hold a spare board.... Alas, it is not.
Thanks for the great solution and the help getting it to work!
-Howie
Thanks Howie!
I try to do the right things. Sometimes it's hard to balance a day job with an old school arcade/gaming/computer repair and parts business, but I give it my best.
As for the chip with the rust on it, it's a simple chip to obtain and replace. When that one finally gives up the ghost, just give me the info off the top of it and I should have it. Until then I wouldn't bother with replacing it. It could last a day, it could last another 20 years, but it's not worth replacing yet.
Raymond
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Well, I checked the resistors... They are fine. I checked the rusted chip... I cleaned out between it and guess what?!!! It works. Not only that, but the RF output is now way cleaner than it was before (it was snowy) and the RCA out works. I guess the rust must've gotten moved just enough to ruin everything.
Unfortunately, however, I'm not getting any audio. Now, that seems like a pretty simple attachment - any ideas why I'm getting nothing there?
-H
You want to ship it to me? I'll see what I can figure out on it. It'll run you parts + shipping both ways. No labor charge as I'm curious as to what went wrong.
There's a chip on that board that is all rusted. That one has me curious, as does the assembly / installation of the kit.
RJ
Make sure the coax braid isn't melting into and touching the center conductor. Also, check the solder point on the capacitor to make sure it's not touching the ground plane next to it.
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Germicidal UV lamps can be found at some aquarium supply stores...
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You want to ship it to me? I'll see what I can figure out on it. It'll run you parts + shipping both ways. No labor charge as I'm curious as to what went wrong.
There's a chip on that board that is all rusted. That one has me curious, as does the assembly / installation of the kit.
RJ
I'll try what you suggest. Unfortunately, the CV is otherwise dead, so I'll check out the resistors - yet be careful to ensure they are fine. Is there a way to test the Caps? Anything I can test... Before I go get another CV...
Thanks - Howie
Looks like it has been assembled correctly, with maybe a possible exception for the resistors. I can't read the color codes on them in the pictures you posted so I can't tell for sure if you put them in the right locations.
Take your multimeter and measure resistance between the center wire and the shield. It's possible you have a short between the two. It doesn't take a lot of heat to melt through the insulation on the center conductor and short the braid to it.
Technically, the ground wire isn't 100% needed as all three grounds (both shield braids and the ground wire) are all connected together on the mod board, so a poor connection where the ground wire solders to the board shouldn't have a negative effect.
RJ
Finally got all my pics taken and uploaded. Here they are:
http://www.flickr.co...57623174446460/
It lets you view everything in various sizes.
Thanks - Howie
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Looks like it has been assembled correctly, with maybe a possible exception for the resistors. I can't read the color codes on them in the pictures you posted so I can't tell for sure if you put them in the right locations.
Take your multimeter and measure resistance between the center wire and the shield. It's possible you have a short between the two. It doesn't take a lot of heat to melt through the insulation on the center conductor and short the braid to it.
Technically, the ground wire isn't 100% needed as all three grounds (both shield braids and the ground wire) are all connected together on the mod board, so a poor connection where the ground wire solders to the board shouldn't have a negative effect.
RJ
Finally got all my pics taken and uploaded. Here they are:
http://www.flickr.co...57623174446460/
It lets you view everything in various sizes.
Thanks - Howie
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Hi I just bought me a 5200 2 port system and no games will load all I get on the tv is a white line that scrolls from the right to left anybody no what might be wrong with it thanks
Hard to say with those symptoms. The most common problem I've seen is bad RAM.
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Colecovision Video Mod
in Hardware
Posted
OK,
The Colecovision A/V Kits I brought back from the MGC event are all listed on the site as of 20 min ago. Also, the +5v memory kits and the dual BIOS kits are listed. I also added 5 of the last 9 Galaga Renewal Kits to the web inventory. The remaining 4 of those will go to rebuild some Galaga arcade game boards I have here at the shop.
http://www.arcadecomponents.com/modkits.html
Instructions for the +5v Memory kits and the Dual BIOS kits plus the Galaga Renwal Kit have been added to the site tonight as well.
http://www.arcadecomponents.com/downloads.html
If you have any problems with the site or with downloads feel free to PM me. Also feel free to kick me in the rear for taking so long to get them done!
Thanks,
RJ