Coleco ADAM Keyboard Daisy Chain From Disk Output Jack?

[Shawn Merrick]

Hello,

I've recently been rebuilding my Coleco ADAM setup, most of which was sold off decades ago.  Now I have a fully classic working system and a newly built ADAM drive emulator (ADE).  All seems well, but I've been informed that I should be able to daisy chain the keyboard off the OUTPUT jack from a physical disk drive.  When attempting this I get no light or function on the keyboard, although this keyboard (and another spare keyboard) work just fine when connected directly to the front or side ADAMNet jacks.  Is there something I am doing wrong?  I can successfully chain 2 physical disk drives without problem, but was advised to get keyboard chained before moving on to ADE coexistence with physical drive.

Thanks for your advice,

     Shawn

 

[Tekman]

Physical disk drives do not pass ADAMnet power to the rear output connector and therefore the keyboard will not get power.

[Tekman]

You have two options.

 

You can attach the ADE to the last physical disk drive out connector since it has it's own power source.

 

You can use a splitter from the console side ADAMnet connector to share with the physical disk drive and ADE at the same time.

 

Both options have you keeping your keyboard attached to the front ADAMnet connector as normal. Also keep in mind that whenever you have a physical disk drive and ADE attached to ADAMnet together, you will need to disable the drive number of the physical drive in the ADE so they won't conflict with each other.

[Shawn Merrick]

3 minutes ago, Tekman said:

You have two options.

 

You can attach the ADE to the last physical disk drive out connector since it has it's own power source.

 

You can use a splitter from the console side ADAMnet connector to share with the physical disk drive and ADE at the same time.

 

Both options have you keeping your keyboard attached to the front ADAMnet connector as normal. Also keep in mind that whenever you have a physical disk drive and ADE attached to ADAMnet together, you will need to disable the drive number of the physical drive in the ADE so they won't conflict with each other.

Thank you so much for this great information!  I am not sure why I found one or two sources telling me the keyboard could plug into the disk drive but I do feel better about my system condition given your prompt response.

So what I really need is a 6P6C line splitter?  I have seen these on eBay or Amazon but did not know if there was any special requirements to watch out for ADAM compatibility.

[Shawn Merrick]

2 hours ago, Tekman said:

Also keep in mind that whenever you have a physical disk drive and ADE attached to ADAMnet together, you will need to disable the drive number of the physical drive in the ADE so they won't conflict with each other.

Although my ADE seems to work great, I have been unable to get it chained off Disk 1 even though I disabled the ADE D1, D3, and D4.  Could this be due to me only wiring pins 1-3 but not the additional 2 ground wires (pins 4-5) on the jack?  Should the 3 ground pins all just be tied together?  Could there be another likely explanation?  MANY THANKS for helpful advice.

     Shawn

[Tekman]

10 hours ago, Shawn Merrick said:

Although my ADE seems to work great, I have been unable to get it chained off Disk 1 even though I disabled the ADE D1, D3, and D4.  Could this be due to me only wiring pins 1-3 but not the additional 2 ground wires (pins 4-5) on the jack?  Should the 3 ground pins all just be tied together?  Could there be another likely explanation?  MANY THANKS for helpful advice.

     Shawn

It could very well be a ground issue. The console itself has all three grounds tied together and the disk drive is only passing one ground to the out connector. Without looking at the schematic, I’m going to guess that your ADE is not getting ground because of that. When I build ADE units, I tie all three grounds together and they work fine when connected to a physical disk drive.

 

It’s an easy continuity test between the ADE ground and console ground to see it you have ground supplied or not. Since all three grounds are tied at the console, you can just touch the probe to the metal shield tabs for the data drives to see.

Edited September 6, 2021 by Tekman

[Tekman]

14 hours ago, Shawn Merrick said:

Thank you so much for this great information!  I am not sure why I found one or two sources telling me the keyboard could plug into the disk drive but I do feel better about my system condition given your prompt response.

So what I really need is a 6P6C line splitter?  I have seen these on eBay or Amazon but did not know if there was any special requirements to watch out for ADAM compatibility.

You can use any 6P6C splitter as long as it’s not a reversed style. The cable from ADAMnet to the splitter will need to be a straight through cable, unlike the typical ADAMnet reverse cable to keep everything correct for using ADAMnet reverse cables out of the splitter.

[Shawn Merrick]

2 hours ago, Tekman said:

When I build ADE units, I tie all three grounds together and they work fine when connected to a physical disk drive.

This is VERY helpful thanks!  Looks like I really should tie the 3 adjacent ground pins together and see if my ADE chains OK from physical drive.  I was also following a video where only one pin 3 ground was wired and that is why I didn't use the additional grounds.

 

The Sean Myers ADE connection diagram shows NOT to connect the +5V pin on the jack at all.  I trust this is correct even though ADAMNet uses all 6 pins, right?

[Tekman]

3 hours ago, Shawn Merrick said:

This is VERY helpful thanks!  Looks like I really should tie the 3 adjacent ground pins together and see if my ADE chains OK from physical drive.  I was also following a video where only one pin 3 ground was wired and that is why I didn't use the additional grounds.

 

The Sean Myers ADE connection diagram shows NOT to connect the +5V pin on the jack at all.  I trust this is correct even though ADAMNet uses all 6 pins, right?

The early ADE connection diagram only used one ground and the reset pin was not used and was added when boot.dsk support was added because a reset was needed to be detected. The newest ADE connection diagram that I created when the PNP transistor was added does show all three grounds connected to the ADE and that would have taken care of any issues you are having. So just connect the three grounds like it shows and you will be good.

 

Could you power the ADE from ADAMnet power, you could, but the current draw of the ADE Arduino Mega2560 and LCD shield is enough to use an external power supply to lessen the burden on the old printer power supply, especially if the console is loaded with expansion cards. If you have a replacement power supply like the Meanwell RT-50A, then it would definitely be safe to power the ADE from ADAMnet power.

[Shawn Merrick]

23 minutes ago, Tekman said:

The newest ADE connection diagram that I created when the PNP transistor was added does show all three grounds connected to the ADE and that would have taken care of any issues you are having. So just connect the three grounds like it shows and you will be good.

I understand all that you said and truly appreciate your contributions to the Coleco ADAM community as well as taking the time for personal responses to my inquiries.  I am NOT a skilled hardware builder, but here was my effort to comply with the connection diagram before I add the additional 2 grounds:

Thanks so much!  I hope to contribute some custom ADAM BBS software I used to sell after transferring to DSK image.

     Shawn

[Tekman]

13 hours ago, Shawn Merrick said:

I understand all that you said and truly appreciate your contributions to the Coleco ADAM community as well as taking the time for personal responses to my inquiries.  I am NOT a skilled hardware builder, but here was my effort to comply with the connection diagram before I add the additional 2 grounds:

Thanks so much!  I hope to contribute some custom ADAM BBS software I used to sell after transferring to DSK image.

     Shawn

Kudos for building your own ADE.

 

Between Sean Myers for developing the ADE and Eric Pearson for developing the SD DDP and MIB boards, the ADAM scene is now better than ever.

[Shawn Merrick]

Having added the 2 additional ground pins to my ADE, works chained to physical disk as expected.  THANKS!!!

[Tekman]

14 minutes ago, Shawn Merrick said:

Having added the 2 additional ground pins to my ADE, works chained to physical disk as expected.  THANKS!!!

Excellent!