Shawn Posted February 13, 2019 Share Posted February 13, 2019 Hello, I'm not super versed in all the different flavors of the Colecovision and revisions it went through but this one I cracked open recently has a "Coleco Ind. Calibration Seal" on it dated from 5/3/1988 with some serious work done to it. There is heavy modification incuding this resistor ladder on one side and diode ladder on the other side of the controller ICs. Anyone come across this before and if so what is the purpose of this modification? Is this something Coleco did or is this unrelated to the calibration it's claiming to have had done to it? Shawn 2 Quote Link to comment Share on other sites More sharing options...
Bmack36 Posted February 13, 2019 Share Posted February 13, 2019 Added Zener Diodes to help with ESD on the controller ports, similar to what is done on the ADAM. Quote Link to comment Share on other sites More sharing options...
Hannacek Posted February 13, 2019 Share Posted February 13, 2019 My Colecovision has the same diodes on the controller ICs. I assume that this was done at the factory to pass quality control. Or the console was brought in for this repair. This is known as a bodge, where they add in stuff later to fix a problem or issue they found at the last minute. I assume they redid the board on later consoles to fix this problem without a bodge, or the bodge was just a precaution, and not necessary, so they didn't do it on later boards. Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted February 13, 2019 Share Posted February 13, 2019 Well, I don't know if the revisions are done in any particular order, but my J revision doesn't have this. Also, those components do not look like resistors to me. The only resistors I've ever seen that had constant girth were 1/2w resistors that we used in electronics class, and they were brown other than the color codes. These look like they were dipped in epoxy and then repainted (notice the paint isn't exactly machine perfect). I can't help but think that these are also some kind of diode or other component. Still, it's weird that they'd do a different mod to player 1 vs player 2. But perhaps only some of them got "the treatment" and they are all the same component? Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted February 13, 2019 Share Posted February 13, 2019 Actually, the color code is violet, green, orange: 753. Same as what's printed on the diodes on the other side. So that confirms it for me, at least. Quote Link to comment Share on other sites More sharing options...
SiLic0ne t0aD Posted February 13, 2019 Share Posted February 13, 2019 Hmmm that's pretty interesting! Never seen that before. I too have a revision J, which is my main unit, but all the other CV's I have do not have any bodges like that. Quote Link to comment Share on other sites More sharing options...
NIAD Posted February 13, 2019 Share Posted February 13, 2019 This was an aftermarket patch to a weak spot of the CV... the controller ICs blowing when hot swapping controllers. It was first implemented as part of CV Delta PCB in the Stand Alone ADAM Memory Console. This fix might have been performed by Honeywell or some other service center. Anyway, none of the CV board revisions left Coleco with this fix implemented as far as I know. 2 Quote Link to comment Share on other sites More sharing options...
Shawn Posted February 14, 2019 Author Share Posted February 14, 2019 Actually, the color code is violet, green, orange: 753. Same as what's printed on the diodes on the other side. So that confirms it for me, at least. Didn't even look that far into it yet. I agree with you on that one. Quick glance I saw 3 color bands and jus thought they might be heavy duty resistors. Didn't even think they would be more diodes at first glance with the other more traditional package diodes on the other side. Quote Link to comment Share on other sites More sharing options...
Shawn Posted February 14, 2019 Author Share Posted February 14, 2019 So it's actually a good idea to add this to protect the controller chips? Quote Link to comment Share on other sites More sharing options...
Ruggers Customs Posted February 14, 2019 Share Posted February 14, 2019 So it's actually a good idea to add this to protect the controller chips? Very good idea. Pulls any esd and runs it straight to ground before it has any chance to hit the controller ics. I actually designed a board that will be sold on Console5's website here in a few weeks. Can also be used on Atari 2600s, etc. 3 Quote Link to comment Share on other sites More sharing options...
Ikrananka Posted February 14, 2019 Share Posted February 14, 2019 But isn't the issue only when hot swapping controllers as NIAD mentioned? In all my years of using CVs, and often with the boards exposed, I have never fried a controller IC or bought one that had a fried IC. Quote Link to comment Share on other sites More sharing options...
Pixelboy Posted February 14, 2019 Share Posted February 14, 2019 But isn't the issue only when hot swapping controllers as NIAD mentioned? In all my years of using CVs, and often with the boards exposed, I have never fried a controller IC or bought one that had a fried IC. Just want to mention that I hope the CollectorVision Phoenix will have similar protection. Quote Link to comment Share on other sites More sharing options...
Shawn Posted February 14, 2019 Author Share Posted February 14, 2019 But isn't the issue only when hot swapping controllers as NIAD mentioned? In all my years of using CVs, and often with the boards exposed, I have never fried a controller IC or bought one that had a fried IC. I have. Pretty recently as well, not even a year ago for sure. I had a thread about here on AA somewhere. Might have been in the hardware forum. Quote Link to comment Share on other sites More sharing options...
Ikrananka Posted February 14, 2019 Share Posted February 14, 2019 (edited) I have. Pretty recently as well, not even a year ago for sure. I had a thread about here on AA somewhere. Might have been in the hardware forum. Yeah, I know that it happens and I have some controller ICs in my spares box for if and when it happens to me. But, I'm seriously interested to understand how it occurs. Is it from hot swapping controllers, touching the pins in the controller ports, both and/or other causes? Edited February 14, 2019 by Ikrananka Quote Link to comment Share on other sites More sharing options...
Shawn Posted February 14, 2019 Author Share Posted February 14, 2019 Yeah, I know that it happens and I have some controller ICs in my spares box for if and when it happens to me. But, I'm seriously interested to understand how it occurs. Is it from hot swapping controllers, touching the pins in the controller ports, both and/or other causes? I'm not totally sure. In my case I think it was hot swapping controllers as I didn't do anything else that would have had any effect that I know of. Quote Link to comment Share on other sites More sharing options...
SiLic0ne t0aD Posted February 14, 2019 Share Posted February 14, 2019 Very good idea. Pulls any esd and runs it straight to ground before it has any chance to hit the controller ics. I actually designed a board that will be sold on Console5's website here in a few weeks. Can also be used on Atari 2600s, etc. Cool. I'll probably buy a couple of these PCBs when they're available. 1 Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted February 14, 2019 Share Posted February 14, 2019 I've gotten CVs used that had blown controller ICs. It was how I got them so cheap! LOL. But yeah pretty sure it is caused by ESD and you would be surprised how far a spark can jump if there is enough current behind it. 2 Quote Link to comment Share on other sites More sharing options...
Ruggers Customs Posted February 15, 2019 Share Posted February 15, 2019 I've gotten CVs used that had blown controller ICs. It was how I got them so cheap! LOL. But yeah pretty sure it is caused by ESD and you would be surprised how far a spark can jump if there is enough current behind it. I've repaired more than a few in the past couple of years. I don't think people realize how many volts can be discharged through ESD. Those controller ICs are only rated for 5.5 volts max for operation and a maximum 7 volts before they break down (if my memory from the datasheet is correct but I could be wrong on that, it's been awhile since I read over it for the 74541 chips). As an example, if someone has a charge built up on their person and they get their finger too close to the metal prongs in the port then they can easily push 1 Kv+ via ESD into those chips. TTL logic or not, those chips are going to fry. The Atari 2600s had this issue as well and there is a similar fix in the field repair manual. Crossbow you're a pretty sharp guy so I know you know all this, I'm just putting this out there for those that don't know. Quote Link to comment Share on other sites More sharing options...
Ruggers Customs Posted February 15, 2019 Share Posted February 15, 2019 Cool. I'll probably buy a couple of these PCBs when they're available. The'll be sold in a set pre assembled. Shooting for around 10 bucks a pair. 4 Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted February 15, 2019 Share Posted February 15, 2019 On modern PCBs, traces where ESD is expected may run close to a ground plane with jagged teeth, aka spark gaps, between traces in order to entice the sudden inrush to jump the gap rather than destroy a semiconductor. Zeners are another solution because they operate normally in reverse breakdown where most semiconductors are destroyed by it. However, I suspect that the ESD brought into the average CV has more to do with it being on carpet or other static-inducing material rather than merely hot-plugging. But that is just a guess with no real proof. 1 Quote Link to comment Share on other sites More sharing options...
Shawn Posted February 28, 2019 Author Share Posted February 28, 2019 The'll be sold in a set pre assembled. Shooting for around 10 bucks a pair. PM sent. Quote Link to comment Share on other sites More sharing options...
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