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Can a ColecoVision 5v Memory Mod be done on a Rev.D (1983) motherboard?


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#1 kerbdog OFFLINE  

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Posted Sun Sep 15, 2013 7:04 AM

Hi folks,
I have a ColecoVision which I want to complete the 5v memory mod on but upon opening I've noticed that the motherboard is different to all of the guides I've found online. Its a 'Rev D' motherboard from 1983.
The motherboard is the same the one in the bottom row of this site here, No on-board RF modulator, while I can see L3 I can't find the L2 coil.

 

Any help would be great.

 

Regards,

Kerb



#2 JamesD OFFLINE  

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Posted Sun Sep 15, 2013 8:13 AM

To answer the title of the thread, yes it can be done though I don't know the specific mods to the board.
I'm sure someone else around here will know how.

If not, that board still uses 4116 RAM chips and there is a mod that will work on any system with those chips.
This page explains how to do a the general mod though the text was aimed at the Apple:
http://picmania.garc...116_to_4164.htm

Doing a mod that way will work on pretty much any computer/game using 4116 RAM chips.
It won't look as clean as removing the -5v signal and replacing +12v with +5v on the motherboard itself but it will work.

Edited by JamesD, Sun Sep 15, 2013 8:26 AM.


#3 Gaztee OFFLINE  

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Posted Sun Sep 15, 2013 9:46 AM

Strangely enough was about to try this on a Revision B board, but the only info I can find is on revision D boards!
:D

Does anyone have any info on doing this mod on a rev b board? It is a French SECAM model if that helps at all?image.jpg

Edited by Gaztee, Sun Sep 15, 2013 9:52 AM.


#4 128Kgames OFFLINE  

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Posted Sun Sep 15, 2013 11:26 AM

Hi folks,
I have a ColecoVision which I want to complete the 5v memory mod on but upon opening I've noticed that the motherboard is different to all of the guides I've found online. Its a 'Rev D' motherboard from 1983.
The motherboard is the same the one in the bottom row of this site here, No on-board RF modulator, while I can see L3 I can't find the L2 coil.

 

Any help would be great.

 

Regards,

Kerb

 

Excuse my ignorance but just what is the "5v memory mod"?



#5 evg2000 OFFLINE  

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Posted Sun Sep 15, 2013 11:49 AM

Here is and explanation and a how to:

http://console5.com/...AM_Modification



#6 kerbdog OFFLINE  

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Posted Sun Sep 15, 2013 3:50 PM

Here is and explanation and a how to:

http://console5.com/...AM_Modification

 

The main board is different to the one in all of the guides including that one, so I'm guessing that no one has done this mod on a Rev.D board?



#7 Gaztee OFFLINE  

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Posted Sun Sep 15, 2013 6:21 PM

 
The main board is different to the one in all of the guides including that one, so I'm guessing that no one has done this mod on a Rev.D board?



Does your board look like the one in the photo in my earlier post??

#8 kerbdog OFFLINE  

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Posted Mon Sep 16, 2013 4:49 AM

Does your board look like the one in the photo in my earlier post??

 

Nearly identical - the only difference is that my one doesn't have the video connector your one has on the right of the picture. All other components (like the RAM, coils) are in the same locations.



#9 Gaztee OFFLINE  

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Posted Mon Sep 16, 2013 5:50 PM

Nearly identical - the only difference is that my one doesn't have the video connector your one has on the right of the picture. All other components (like the RAM, coils) are in the same locations.


My mate is going to try the solution mentioned in post 2 here. He thinks its doable. Will let you know how he gets on.

#10 kerbdog OFFLINE  

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Posted Tue Sep 17, 2013 5:07 AM

My mate is going to try the solution mentioned in post 2 here. He thinks its doable. Will let you know how he gets on.

 

Sweet! If possible if photos could be posted that would be great!



#11 Gaztee OFFLINE  

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Posted Tue Sep 17, 2013 5:24 AM

Sweet! If possible if photos could be posted that would be great!

I'll ask him to do that too :) He just text me to let me know he plans to make a guide for it :)

Edited by Gaztee, Tue Sep 17, 2013 5:47 AM.


#12 Gaztee OFFLINE  

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Posted Tue Sep 17, 2013 5:50 PM

My friend has done this mod using the technique suggested in post 2. He will put a guide together soon & post it here.

#13 JamesD OFFLINE  

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Posted Tue Sep 17, 2013 11:26 PM

Just an FYI, +5v, -5v and 12v all probably have single origins into the RAM circuit making the mod much easier.
If you follow the traces back from each of those pins you should be able to cut traces or something to eliminate doing all the jumper wires. It helps to have a multitester to test for continuity.
I should have mentioned that before.

Cut the -5v source. That should take care of all the NC connections at once.
Cut the +12v source and jumper +5v in it's place. That should connect all the new +5 pins at once.
Since +5v already goes to the chips, just find where it comes in and jumper from there.
Much easier.

#14 JamesD OFFLINE  

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Posted Wed Sep 18, 2013 6:38 AM

And before someone starts cussing me... just make sure you don't make any of those mods past other circuits that need those power signals.

#15 LoTonah OFFLINE  

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Posted Fri Sep 20, 2013 5:30 AM

Dumb question: would this mod be beneficial, or even compatible, with the ADAM?  I have the stand-alone version.



#16 kerbdog OFFLINE  

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Posted Fri Sep 20, 2013 5:51 AM

My friend has done this mod using the technique suggested in post 2. He will put a guide together soon & post it here.

 

Hey Gaztee, great to hear that your friend has done the mod on the Rev.D board. Did he get a chance to put together the guide yet? Would be great to get so I can get my Coleco back up and working :D



#17 omf OFFLINE  

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Posted Fri Sep 20, 2013 8:25 AM

 

Hey Gaztee, great to hear that your friend has done the mod on the Rev.D board. Did he get a chance to put together the guide yet? Would be great to get so I can get my Coleco back up and working :D

 

i am the one who Gaztee was talking about, i was going to do a nice guide with pictures but seing as this is wanted sooner rather than later, here is an 'ultra breif' overview of the process


1    remove the two coils (these are for +12V and -5V
2    solder a cable between the two points shown in yellow
3    remove the old ram (not a terribly easy task)
4    solder in provided sockets
5    insert new ram chips
6    put console together again

Attached Thumbnails

  • remove coils.jpg
  • replace 12v with 5 v.jpg
  • sockets with cable.jpg


#18 kerbdog OFFLINE  

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Posted Fri Sep 20, 2013 12:34 PM

Your a gent sir! Will have a go at this in the coming day or so and report back :)



#19 JamesD OFFLINE  

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Posted Fri Sep 20, 2013 6:57 PM

Dumb question: would this mod be beneficial, or even compatible, with the ADAM?  I have the stand-alone version.

Yup, I have 2 ADAMs I plan on modding myself, I just need to order chips and sockets.
The video RAM is on the circuit board with the VDP. The top board if that makes more sense.

#20 NIAD OFFLINE  

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Posted Fri Sep 20, 2013 7:33 PM

Yup, I have 2 ADAMs I plan on modding myself, I just need to order chips and sockets.
The video RAM is on the circuit board with the VDP. The top board if that makes more sense.

That's the ColecoVision Delta Board (with the cartridge slot to be exact) and the bottom board is called the ADAM Logic Board (has the three Expansion Slots). Wish I had the soldering skill set like you and others to perform tasks such as this and installing an F18A VGA Board.



#21 JamesD OFFLINE  

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Posted Sat Sep 21, 2013 12:05 AM

That's the ColecoVision Delta Board (with the cartridge slot to be exact) and the bottom board is called the ADAM Logic Board (has the three Expansion Slots). Wish I had the soldering skill set like you and others to perform tasks such as this and installing an F18A VGA Board.

I consider desoldering to be worse than soldering.
It just takes decent tools and a little practice.

#22 JamesD OFFLINE  

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Posted Sat Sep 21, 2013 10:33 AM

I didn't open up an ADAM to take pics, but the schematics clearly show the +12v and -5v input for the RAM.
The schematics aren't totally readable but I believe the coils are labeled L2 and L3 just like the regular game system.
(the game board is actually the same as the regular Colecovision isn't it?)

#23 NIAD OFFLINE  

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Posted Sat Sep 21, 2013 1:56 PM

The CV Delta Board in the ADAM is pretty much identical to the PCB in the ColecoVision with the exception of a few things being re-arranged and modded:

 

- the controller ports are moved to the right side

- the  Expansion Bus is moved to the back

- IIRC the RAM chips are moved to the front/left

- a Composite Video mod with audio is made for the DIN Video port and Composite only Video Port

- the troublesome Power Switch from the CV PCB is removed seeing as the power supply.switch is part of the Printer

 

etc., etc. So Coleco didn't actually stop manufacturing ColecoVision boards, they just stopped making ColecoVision specific PCBs and systems in the big run-up to the ADAM's release. 



#24 kerbdog OFFLINE  

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Posted Sun Jan 19, 2014 2:16 PM

Just got around to do this work :( ended up getting a hot air rework station to remove the pins after I cut the IC legs off.

Powered it all back on again and the video is corrupted but the sound is fine which is strange. Any suggestions what the next thing to check might be?

 

Note, I've already swapped the power switch to be a double throw switch and also I've checked the power output of the PSU and its fine.


Edited by kerbdog, Sun Jan 19, 2014 2:32 PM.


#25 kerbdog OFFLINE  

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Posted Mon Jan 20, 2014 6:49 AM

Video of issue:


Edited by kerbdog, Mon Jan 20, 2014 7:11 AM.





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