channelmaniac

Is anyone interested in doing this? I just pulled the trigger on 30 circuit boards for a Colecovision A/V mod based off of this circuit. The board came out to a hair over 1" by a hair under 1" in size and was laid out by using the EAGLE Layout Editor 5.2.0. It was trial and error to get the schmatic laid out and then the board laid out correctly. We'll find out in 3 weeks how the boards turn out. I was thinking that if there were some hardware junkies out here that either have or wanted to create custom boards we could get a discussion going. I've learned a few things on the software and could offer some limited pointers on getting started and would like to learn more from folks that have used it more than I have. The EAGLE software is freeware for non-commercial use. Since I'm commercial, I need to go pay for it. And why not... it's a good tool and seems to be worth it. You can download it from www.cadsoft.com if you want to give it a try. RJ

Can you post a picture? Does it boot to the garbled mess even with a cartridge out? If it looks good with the cartridge out then suspect a dirty slot or cart. If not, check the power supply, switch, and the 4116 DRAM ICs. Raymond

Where are you located and which version of the heavy 6er do you have? Is it the one with the rainbow ribbon cable or the one with the thin plastic cable? I have a couple of extra boards over in storage but not sure how much shipping would be to you. I'm in the Dallas, TX, area.

Sounds like there is a problem on the VDP internally and they just connected the 2 pins rather than replacing the VDP as a short cut to at least get a picture.

The 4116 DRAMs are sensitive to power issues moreso than heat. Granted, if they are running hot enough that it's uncomfortable to hold your finger on them, then yes, heatsinks will help. That's rarely the case on these DRAMs though. On the arcade games if you have cracked solder joints on the +12v and -5v supply connectors you'll start randomly popping DRAMs. Williams games are bad about that. One of the fixes is to resolder the connector or replacing it if it's arced and burned from the current trying to cross the cracks. Of course, the biggest fix is to mod the board for 4516 or 4164 DRAMs.

You should be able to find a cheapo +5 to -5v inverter in a 24 pin package that will make easy work of it. RJ

Broken switch or bad RIOT chip.

OK, First off, the -20 refers to 200 nanoseconds and NOT 20. -15 refers to 150ns. Anything the same speed or faster will work... -20, -15, -12, and -10 are all pretty easy to find. If you want to experiment you might even be able to modify the unit to take different DRAM ICs. It's common to modify the Williams games that take 4116 DRAM to take 4516 (5v only 16k DRAM) or 4164 DRAM which would be more reliable and would NOT require the +12v and -5v supplies. There are a lot of different part numbers for 4116 DRAM and they are compatible. Each manufacturer did their own thing. Just make sure to use good quality double-wipe sockets when replacing any chip so future repairs can be done easily. I have a stack of Colecovision boards for parts and will be testing the chips. Any good VDP chips will be added to my website but it'll probably be another month before I get that done. RJ

Anyone have a good power supply to sell? I know they are $6.99 + shipping on eBay... I just *hate* doing things on eBay since their feedback policy changes went into effect. Thanks, RJ

Clearly. Someone want to tell me how to do it correctly, as I just "Send Money" back to them. I've been using PayPal since 1999 and have never noticed any other way to do it. PLEASE enlighten me -- someone, anyone! Go to the "Details" screen for the payment in question and you'll see a refund link. Click it. Do a partial refund from that screen for that payment and you'll see where the fees are partially credited when it's processed. I do it for folks that place mulitple orders in a day or 2... or that contact me about placing another order and to put one on hold to combine them. It's easy to do and saves you on fees. RJ

Generally you can go faster with the chips without problems. 120ns cycle time can be used in place of 150ns cycle time but usually not the other way around. It's not that the chip cycles that fast by itself it's that it can cycle that fast if the signals coming to it are that fast. RJ

If all else fails, a bad RAM will cause this as well... but is far less likely than the switch or power supply problems.

OK, So I received the Vectrex & cartridge and the Neo CDZ for parts from him. However, I have *not* received the JAMMA board I also paid him for. GRRRR... He hasn't communicated anything back to me in a couple of weeks now about that last board.

It wasn't a bad arcade game but it was very hard and unforgiving I had a Berzerk arcade game local around 82 83 Didnt play it that much though I have to say Battlezone. Park yourself next to a tall cube and be protected from the missiles. Get enough points and get a free game. (over & over & over) I could play for 30 minutes on a quarter.

Here's a great story of when he was asked to participate in a Secret Service RAID... http://www.dadhacker.com/blog/?p=1031 It hit an alias at work today.

I picked up a bunch of dead 2600s for parts. If you need cartridge connectors on the hardware surrounding the cart connector itself then email me. RJ

It all depends on what I'm cleaning as to what I'll use. No matter what method you use, remove batteries from the board. If you cannot remove the battery (suicide batteries come to mind) then you must take extra care as to how you clean the board. I'm not discussing that type of cleaning here. For really nasty boards I throw them in the dishwasher with hot water and NO soap and NO heat dry as the soap can leave bad residue and the heat dry can melt plastics. For others it really depends on what the spill is. I'm partial to Formula 409 and a tooth brush for most. Oily stuff like battery residues gets the 409 Orange cleaner and a tooth brush. Rinse with water and dry well. I typically put the board in front of a fan to let it dry. And I'll say this: Yes, dishwashers work... Sounds crazy but I used to work in a grey market Apple repair depot back in the mid 90s and we used that method on boards we gave 90 day and 6 month warranties on. We never had a board come back for repair that was a problem related to the cleaning method.

Nice site! I have to throw one in there just for fun.

Don't recall what the SVAII looked like... open the lid and look to see if those are light bulbs. If they are then maybe you can mod it with some current limiting resistors and LEDs to make it light up with almost no heat. Measure the voltage being supplied to the bulbs, find the voltage and current needed for the LEDs (spec sheets!), and do a little bit of math and you'll find the resistor size needed to give max brightness for the LED. Make the resistor value higher to make the LED dimmer. Take the voltage supplied and subtract the LEDs operating voltage. Divide that by the LED current in amps. LED current is specified in mA (milliamps) so 10mA would be ".010" amps. If the voltage supplied was 12v and the LED operated from 1.2v and 10ma of current it would be (12-1.2)/.010 to find the resistor size needed. In this case 1080 ohms or, simply 1000 ohms since that's common value. Next bigger size common value to find resistors in would be 1.2k or 1200 ohms. RJ

You have to use a germicidal UV lamp of the right wavelength and not a "blacklight" bulb. +1 on the enclosure. UV light will sunburn you and damage your eyes. RJ

$3.99 + the EPROM and shipping. The website has already been updated with the pricing change.

Is it using heat seal tape on both ends of the connection? If so, that sucks... that stuff isn't very easy to find.

Actually it does matter. You can open a PayPal account with a free checking account or with a credit card. Simply cancel those accounts an PayPal won't notice until it goes to pull money out to reimburse people. If there's no account attached then there's no way to pull from it. Or, if that account is empty then there's no way to pull from it either. Don has contacted a number of us over there and many folks have received their items. I was promised on the 12th that mine would be shipped to me via USPS Priority Mail with Delivery Confirmation. I'm waiting patiently to see if he comes through. Raymond

Not really, I just know how to do a few things with it. Want good advice, there's another person here who knows more than I do, and I imagine Ben Heckendorn would be able to help with a screen upgrade. You find a replacement screen yet? If not, I might be able to find you one at a local junk store. They had a handful of Game Gear units as-is pretty cheap. RJ

http://www.therealbobroberts.net/parts.html#atari Bob carries the stainless steel rollers you need to replace. Those will help it roll like new again.