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digress

Can only run 32k cartridges but not Ultimate multicart or a megarom cart

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I have 1 fully operational colecovision ... and another that operates but will only run 32k cartridges. If I put in the Ultimate multicart or a megarom cart it will not run. Multicart gets the splash screen and then goes blank. It seems to have problems with the bank switching. Just wondering if anyone has a suggestion .. other than blowing into the cartridge slot.

 

Attached is pictures( more gold & yellow) of the coleco mother boards top & bottom from the system that will only run 32k carts

 

And yes, it has a modified power switch but that was only installed last night and the problem predates it.

 

32k roms only board

32k roms only board bottom

 

 

And here is the fully working system ( more green & silver) of the coleco mother boards top & bottom from the system that will run all cartridges carts

 

All roms working including multicart & megaroms board

All roms working including multicart & megaroms board bottom

Edited by digress
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Have you tried the power adapter from the working system into the non working system yet?

 

If not I would try that first to make sure it is not a power issue that the above and beyond carts do not have enough power to function but the power is good enough to work on the 32K carts.

 

We have that easy tell with Lord of the Dungeon. If it doesn't work but every other cart works then that means your power is starting to go.

Edited by ColecoDan
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Yeah I used the same power supply for both systems. I'll try an additional power supply or 2 I have. I agree it does seem to be a power issue as the multicart must use more. But does a megacart use more? I doubt it. It's interesting though as the regular carts work flawlessly. I can't see dirt or anything in the pins either. or and extra blobs of solder or anything obvious. This system has been like it since I got it second hand.

 

It's actually the main reason I replaced the power button with a new switch as I thought that might be it.

 

 

Have you tried the power adapter from the working system into the non working system yet?

 

If not I would try that first to make sure it is not a power issue that the above and beyond carts do not have enough power to function but the power is good enough to work on the 32K carts.

 

We have that easy tell with Lord of the Dungeon. If it doesn't work but every other cart works then that means your power is starting to go.

Edited by digress

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I've some theories about the non-working feature:

 

1. One of your chips is so oxydized that is eating more energy than necessary (you could check it measuring voltage in both Colecovision)

 

2. One of the decoder chips 74LS138 / 74LS04 is oxydizing so it became slower.

 

3. The Colecovision that doesn't work uses a NEC PD780 CPU, it has been recognized that it is a Japanese reimplementation that behaves slightly different than a real Z80A (Z8400A), BTW the Z80 without A is limited to 2 mhz.

 

My Colecovision has a green board and works just fine, I'm going to open it just to make sure what processor it uses, as my theory 3 is just plain interesting and looks promising. :)

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Yeah, let me know if you have that same NEC PD780 CPU or the z80a. That would be an easy replacement... well kind of. once I idesolder the current cpu . solder easy... unsolder is hard.

 

 

I've some theories about the non-working feature:

 

1. One of your chips is so oxydized that is eating more energy than necessary (you could check it measuring voltage in both Colecovision)

 

2. One of the decoder chips 74LS138 / 74LS04 is oxydizing so it became slower.

 

3. The Colecovision that doesn't work uses a NEC PD780 CPU, it has been recognized that it is a Japanese reimplementation that behaves slightly different than a real Z80A (Z8400A), BTW the Z80 without A is limited to 2 mhz.

 

My Colecovision has a green board and works just fine, I'm going to open it just to make sure what processor it uses, as my theory 3 is just plain interesting and looks promising. :)

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Yeah, let me know if you have that same NEC PD780 CPU or the z80a. That would be an easy replacement... well kind of. once I idesolder the current cpu . solder easy... unsolder is hard.

 

if you do unsolder, the method below has worked well for me:

 

1-snip leg

2-heat leg, pull leg out with tweezer nose pliers

3-use de-solder wick to clean up old solder, if wick is old it might need fresh flux

4-clean off flux with flux remover as needed (or alcohol), old soft tooth brush is good to use if careful, just don't lift any pads

5-solder in new socket, might be easier to clean up flux at this stage as new solder helps to keep pads down

6-put replacement z80 in the new socket

Edited by grips03

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Ok, I've opened my Colecovision, it has a green PCB and I had the surprise it uses a NEC PD780 CPU, even older than yours, mine is from 1982.

 

Still yours could be oxydized or slightly damaged (data bus is not protected), but anyway you have a good start for options (voltage measurement, Z80, 74LS04 and 74LS138)

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Almost I've forgot it, have you tested Defender?, this cartridge uses 24K of addressing space, just to check if cartridge is being accessed right. It could be so simple as a bad address line.

 

I remember there are 32K cartridges, but at this moment I cannot remember one.

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Almost I've forgot it, have you tested Defender?, this cartridge uses 24K of addressing space, just to check if cartridge is being accessed right. It could be so simple as a bad address line.

 

I remember there are 32K cartridges, but at this moment I cannot remember one.

 

If I'm not mistaken, the following are 32k:

 

- 2010

- Alcazar

- Cabbage Patch Kids Picture Show

- Dam Busters

- Destructor

- Galaxian

- Smurf Paint N' Play

- Star Trek

- All Super Action sports carts

 

And I'm sure there's a bunch more.

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As far as 32K ColecoVision games, indeed there are a good number of them, but a lot depends on how the game was dumped as well:

 

- If the cart was dumped using an ADAM Computer with a program called CopyCart v2.0 and the resulting rom dump file size is 32K, then the game was truly 32K in size. CopyCart dumps only the actual size of the game.

- A certain new cart dumper automatically creates a 32K rom dump file even if the actual cart was only 8K on up to 24K. This is the best method in my mind seeing as you are guaranteed to dump the entire contents of the cart (Super Cobra and Galaxian were not properly dumped until about a year ago and actually are not a full 32K cart, but by using this method a good dump was finally made) even though the resulting file might be oversizes and you would have to use an editor program to verify. Anyway, leave the file alone even if it is an overdump.

- Dump each Prom/Eprom chip with a Reader and then rejoin each resulting file to make a complete dump.

 

Anyway, these are the 32K carts that I know of, but would have to use an editor to look at the file contents to see if they are true 32K carts:

 

- 2010

- Dam Busters

- Destructor

- Dukes of Hazzard

- Fortune Builder

- It's Only RnR

- Rock 'n Bolt

- Spy Hunter

- Super Action Football

- Super Action Football (Soccer)

- Tapper

 

Alcazar is a 16K and CPK: Pic Show, Smurf PnP and Star Trek are 24K carts. Again, the games listed above would have to be verified via an editor as to whether they are truly 32K in size, but I think they all are.

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If you have homebrew carts. All my games are 32k. Ghos't n Zombie , Smurf challenge and Exploding Foot. And i use the totality of bytes available! (GnZ rom was exactly 32768 bytes! for the 2 others only 4 or 5 bytes miss to reach the limit. )

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If you have homebrew carts. All my games are 32k. Ghos't n Zombie , Smurf challenge and Exploding Foot. And i use the totality of bytes available! (GnZ rom was exactly 32768 bytes! for the 2 others only 4 or 5 bytes miss to reach the limit. )

Yeah, everyyone already knows that you are Mr. 32K! :lolblue:

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Ok so I tried a second power supply with the same results. So it doesn't seem to be that

 

Now I've tried a number of original cartridges

 

Worked:

Donkey Kong

BC's Quest for tires

Alcazar

Gorf

Popeye

James Bond

Frogger

 

Not working:

 

Defender ( i got the title screen only once)

Frenzy (thought it do get the title screen)

Rocky (tried 4 differnt carts that I have 1 went all the way to game selection before dyingin a pile of speghetti graphics)

Destructor

Football

Spy Hunter

 

When the games do work they work flawlessly. It seems to be the addressing issue with the larger size roms.

 

I'll try to clean what I can.

 

Thanks for all the suggestions.

 

 

As far as 32K ColecoVision games, indeed there are a good number of them, but a lot depends on how the game was dumped as well:

 

- If the cart was dumped using an ADAM Computer with a program called CopyCart v2.0 and the resulting rom dump file size is 32K, then the game was truly 32K in size. CopyCart dumps only the actual size of the game.

- A certain new cart dumper automatically creates a 32K rom dump file even if the actual cart was only 8K on up to 24K. This is the best method in my mind seeing as you are guaranteed to dump the entire contents of the cart (Super Cobra and Galaxian were not properly dumped until about a year ago and actually are not a full 32K cart, but by using this method a good dump was finally made) even though the resulting file might be oversizes and you would have to use an editor program to verify. Anyway, leave the file alone even if it is an overdump.

- Dump each Prom/Eprom chip with a Reader and then rejoin each resulting file to make a complete dump.

 

Anyway, these are the 32K carts that I know of, but would have to use an editor to look at the file contents to see if they are true 32K carts:

 

- 2010

- Dam Busters

- Destructor

- Dukes of Hazzard

- Fortune Builder

- It's Only RnR

- Rock 'n Bolt

- Spy Hunter

- Super Action Football

- Super Action Football (Soccer)

- Tapper

 

Alcazar is a 16K and CPK: Pic Show, Smurf PnP and Star Trek are 24K carts. Again, the games listed above would have to be verified via an editor as to whether they are truly 32K in size, but I think they all are.

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Ok so I tried a second power supply with the same results. So it doesn't seem to be that

 

Now I've tried a number of original cartridges

 

Worked:

Donkey Kong

BC's Quest for tires

Alcazar

Gorf

Popeye

James Bond

Frogger

 

Not working:

 

Defender ( i got the title screen only once)

Frenzy (thought it do get the title screen)

Rocky (tried 4 differnt carts that I have 1 went all the way to game selection before dyingin a pile of speghetti graphics)

Destructor

Football

Spy Hunter

 

When the games do work they work flawlessly. It seems to be the addressing issue with the larger size roms.

 

I'll try to clean what I can.

 

Thanks for all the suggestions.

Great! then you almost have it! download a Z80 pinout and Colecovision cartridge pinout and try to follow PCB trace for A14 with a multimeter. Also there is a 74LS138 that could be the culprit as it decodes the upper address range ($c000-$ffff)

 

Check Colecovision schematics at http://atarihq.com/danb/Colecovision.shtml

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Actually what we learned is he is getting lazy and we are missing out on 4 or 5 bytes in the new games. :)

 

No, it is just a cost cutting strategy! :D 4 bytes not coded save a lot on production cost!

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digress, do you have any updates on this issue?

 

My "special" ColecoVision seems to have a similar issue. I'm not sure if it's any of the parts, or if it's power related, or the circuit layout. I've ordered an official Zilog Z80 as well as a couple of newer 74..138 and 74..04 chips to see if that makes a difference. I'll update here if I find anything.

 

Also, can anyone confirm whether the below working games are 16K and the non-working games are 16+K?

 

Worked:

Donkey Kong

BC's Quest for tires

Alcazar

Gorf

Popeye

James Bond

Frogger

 

Not working:

 

Defender ( i got the title screen only once)

Frenzy (thought it do get the title screen)

Rocky (tried 4 differnt carts that I have 1 went all the way to game selection before dyingin a pile of speghetti graphics)

Destructor

Football

Spy Hunter

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digress, do you have any updates on this issue?

 

My "special" ColecoVision seems to have a similar issue. I'm not sure if it's any of the parts, or if it's power related, or the circuit layout. I've ordered an official Zilog Z80 as well as a couple of newer 74..138 and 74..04 chips to see if that makes a difference. I'll update here if I find anything.

 

Also, can anyone confirm whether the below working games are 16K and the non-working games are 16+K?

 

The working games are all 16K, the others are mixed 24K / 32K.

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I havn't gotten to the next test yet. I have to trace the a14 with a multimeter . I will try that today or tomorrow and update. I would love to restore this system to fully working.

 

digress, do you have any updates on this issue?

 

My "special" ColecoVision seems to have a similar issue. I'm not sure if it's any of the parts, or if it's power related, or the circuit layout. I've ordered an official Zilog Z80 as well as a couple of newer 74..138 and 74..04 chips to see if that makes a difference. I'll update here if I find anything.

 

Also, can anyone confirm whether the below working games are 16K and the non-working games are 16+K?

 

 

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I just tried a Zilog Z80 chip in place of the NEC clone in my "special" ColecoVision. This was only a quick test, but the first results are indicating that this has fixed the issue I was having with the 128-in-1 flash cart and some other carts.

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Ok so I tried a second power supply with the same results. So it doesn't seem to be that

 

Now I've tried a number of original cartridges

 

Worked:

Donkey Kong

BC's Quest for tires

Alcazar

Gorf

Popeye

James Bond

Frogger

 

Not working:

 

Defender ( i got the title screen only once)

Frenzy (thought it do get the title screen)

Rocky (tried 4 differnt carts that I have 1 went all the way to game selection before dyingin a pile of speghetti graphics)

Destructor

Football

Spy Hunter

 

When the games do work they work flawlessly. It seems to be the addressing issue with the larger size roms.

 

I'll try to clean what I can.

 

Thanks for all the suggestions.

 

You have a bad 74LS138 or one the CS lines to the cartridge is bad.

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It is normal that at some point a Colecovision fails, in the case of my Colecovision I hope than that will be in 100 years :D

 

Chips can oxydize, traces can oxydize (though the mask helps to protects them,) or it is simply static happening during cartridge insertion that spreads along a chip like a lightning destroying or weakening internal connections.

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Thanks, I'm definitely going to look into this. I have been sidetracked the past 2 months with a number of other projects including my first kids book

 

www.piggyhockey.com

 

And my usual stuff. I'm going to check these 2 suggestions.

 

You have a bad 74LS138 or one the CS lines to the cartridge is bad

 

I just tried a Zilog Z80 chip in place of the NEC clone in my "special" ColecoVision. This was only a quick test, but the first results are indicating that this has fixed the issue I was having with the 128-in-1 flash cart and some other carts.

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