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838-PEB


Shift838
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For the last few months I have been working on some new projects.  One of them is the beginning of a newly designed PEB.  I've been taking feedback and suggestions from selected TI'ers and tried to incorporate what I think will be beneficial.  This all started originally as I wanted to just create a frameless PEB for my benchtop testing that would take older PC AT and ATX power supplies without having to splice. 

 

Don't get your hopes up yet, I still have to design the frame and case around the board and power supply.

 

I do have a sheet metal brake to work on the case and plan on using some aluminum x channels for framing.

 

I did order the PCB's along with others a few prototype PCB's i have been working on a few weeks back and got them all in to start testing the prototype board. (I'll post the others in a separate thread)  I have checked all the traces to make sure everything was accurate and delivering the power required to the correct PEB Bus pins for the expansion cards as well as all other lines.  All have tested good signals are testing good.

 

The board is bigger than the original backplane bus board in the original TI PEB, but I should still be able to make the PEB a bit smaller as the power supplies will fit nicely behind any floppy or hard drives that are mounted.  My initial thought is with all the removable media type drives out there to simulate hard drives and floppy drives is how I want to design this for but the bay will be big enough to accommodate real iron floppy drives if necessary I'm thinking.  I'll start to figure that out once I start creating the actual case.

 

The case will utilize sheet metal, aluminum framing and plastic parts along with some 3D printed parts most likely.

 

The new backplane board will not fit for the original PEB so don't try that as the board is not a direct replacement.  

 

Key features:

 

  • 8 standard expansion board slots (just like the original)
  • connectors for 2 x 12v Fans
  • Choose your own Power supply 
    • Older PC AT power supply (P8 connector)
    • ATX Power supply
  • +VCC Selectable
    • Select between 5v or 12v to be delivered to pin #1 and #2 of the PEB cards
      • If your cards have been modified to remove the voltage regulator you will select 5v.

I used a screw terminal for this in order to ensure I could get the traces wide enough to handle the current.  Using a terminal jumper designed for this part to select between 5v or 12v.  As seen in the photo it is currently selected for +5v.

  • header connectors for:
    • Power LED header (mount a LED for frameless install or use it as a header to run a pre-wired LED to a front panel)
    • PC Type Latching Power Switch (for ATX Power)
    • Latching switch for power (choose your own for ATX powering)
    • Geneve 9640 Reset switch headers to connect to bottom leg of R62 of Geneve
  • Ground planes on both Top and Bottom of board.

 

See attached rendering and partially assembled board. I still need to solder the PEB IO connectors to the board.

 

comments welcomed.

 

 

838PEB-Render.png

838PEBv1-1.jpg

Edited by Shift838
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  • 6 months later...
On 8/2/2021 at 9:49 AM, Shift838 said:

For the last few months I have been working on some new projects.  One of them is the beginning of a newly designed PEB.  I've been taking feedback and suggestions from selected TI'ers and tried to incorporate what I think will be beneficial.  This all started originally as I wanted to just create a frameless PEB for my benchtop testing that would take older PC AT and ATX power supplies without having to splice. 

 

Don't get your hopes up yet, I still have to design the frame and case around the board and power supply.

 

I do have a sheet metal brake to work on the case and plan on using some aluminum x channels for framing.

 

I did order the PCB's along with others a few prototype PCB's i have been working on a few weeks back and got them all in to start testing the prototype board. (I'll post the others in a separate thread)  I have checked all the traces to make sure everything was accurate and delivering the power required to the correct PEB Bus pins for the expansion cards as well as all other lines.  All have tested good signals are testing good.

 

The board is bigger than the original backplane bus board in the original TI PEB, but I should still be able to make the PEB a bit smaller as the power supplies will fit nicely behind any floppy or hard drives that are mounted.  My initial thought is with all the removable media type drives out there to simulate hard drives and floppy drives is how I want to design this for but the bay will be big enough to accommodate real iron floppy drives if necessary I'm thinking.  I'll start to figure that out once I start creating the actual case.

 

The case will utilize sheet metal, aluminum framing and plastic parts along with some 3D printed parts most likely.

 

The new backplane board will not fit for the original PEB so don't try that as the board is not a direct replacement.  

 

Key features:

 

  • 8 standard expansion board slots (just like the original)
  • connectors for 2 x 12v Fans
  • Choose your own Power supply 
    • Older PC AT power supply (P8 connector)
    • ATX Power supply
  • +VCC Selectable
    • Select between 5v or 12v to be delivered to pin #1 and #2 of the PEB cards
      • If your cards have been modified to remove the voltage regulator you will select 5v.

I used a screw terminal for this in order to ensure I could get the traces wide enough to handle the current.  Using a terminal jumper designed for this part to select between 5v or 12v.  As seen in the photo it is currently selected for +5v.

  • header connectors for:
    • Power LED header (mount a LED for frameless install or use it as a header to run a pre-wired LED to a front panel)
    • PC Type Latching Power Switch (for ATX Power)
    • Latching switch for power (choose your own for ATX powering)
    • Geneve 9640 Reset switch headers to connect to bottom leg of R62 of Geneve
  • Ground planes on both Top and Bottom of board.

 

See attached rendering and partially assembled board. I still need to solder the PEB IO connectors to the board.

 

comments welcomed.

 

 

838PEB-Render.png

838PEBv1-1.jpg

Looks like a great project.

What about keeping the existing PEB but replace the outdated power supply boat anchor with a typical PC ATX style power suppy instead.

Just wondering if anybody has done that upgrade before.

 

Roger

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1 hour ago, rgjt said:

Looks like a great project.

What about keeping the existing PEB but replace the outdated power supply boat anchor with a typical PC ATX style power suppy instead.

Just wondering if anybody has done that upgrade before.

 

Roger

People have replaced the PEB power supply with a ATX style power supply after removing it from its enclosure.  There are a few posts of step by step to do so.  this board is going to be for a whole new PEB enclosure that is on my plans to do.

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9 minutes ago, Shift838 said:

People have replaced the PEB power supply with a ATX style power supply after removing it from its enclosure.  There are a few posts of step by step to do so.  this board is going to be for a whole new PEB enclosure that is on my plans to do.

That is one ambitious project. I'm sure that when you complete the project, many users will probably upgrade their systems with it.

 

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16 minutes ago, rgjt said:

That is one ambitious project. I'm sure that when you complete the project, many users will probably upgrade their systems with it.

 

yes, it is ambitious.  I am waiting for my sheet-metal brake to get here before I start on it.  The good thing is I have the IO board made and it takes as you see a standard AT and ATX power connectors.  I am using one of them now on my test bench and have been for the last 6 months.

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5 minutes ago, Shift838 said:

yes, it is ambitious.  I am waiting for my sheet-metal brake to get here before I start on it.  The good thing is I have the IO board made and it takes as you see a standard AT and ATX power connectors.  I am using one of them now on my test bench and have been for the last 6 months.

Did you ever consider using a typical PC styple computer case that already has the ATX power supply and drive bays?

It might be quite easy to install your IO board in the same area where the motherboard would be installed.

Just a tought.

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Just now, rgjt said:

Did you ever consider using a typical PC styple computer case that already has the ATX power supply and drive bays?

It might be quite easy to install your IO board in the same area where the motherboard would be installed.

Just a tought.

I did that a few years ago, but before I designed the new PEB IO board.  The biggest drawback at the time was since I was installing everything in this case, even the 99/4A mainboard it was very cramped.  i had to be able to get the Flex cable interface and that was tricky to get it snake through the case.  Everything was in the same case, so all I had to do weas flip 2 different power switches, one for the PEB cards and teh other for the 4A.  It's still running today..  

 

If you want to read about it and see photos, check the thread out 

 

New Project for my 4A and PEB - TI-99/4A Computers - AtariAge Forums

 

It's a good thought for a new PEB though to make the new board just fit into a ATX style case.  Plug in and go..  One thing I will need to design is a Card cage or a railing system to clampe over the cards to keep them all in place if the unit is standing up.

 

 

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15 minutes ago, Shift838 said:

I did that a few years ago, but before I designed the new PEB IO board.  The biggest drawback at the time was since I was installing everything in this case, even the 99/4A mainboard it was very cramped.  i had to be able to get the Flex cable interface and that was tricky to get it snake through the case.  Everything was in the same case, so all I had to do weas flip 2 different power switches, one for the PEB cards and teh other for the 4A.  It's still running today..  

 

If you want to read about it and see photos, check the thread out 

 

New Project for my 4A and PEB - TI-99/4A Computers - AtariAge Forums

 

It's a good thought for a new PEB though to make the new board just fit into a ATX style case.  Plug in and go..  One thing I will need to design is a Card cage or a railing system to clampe over the cards to keep them all in place if the unit is standing up.

 

 

It would simply things quite a bit IMO and provide all the floppy/disk drive power in a modern style case. Making the railing support cage would be quite simple especially if one would use the existing setup in the PEB assuming your IO board spacing is the same.

Regardless, good stuff for the old TI99/4A.

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  • 2 months later...

I had some time while I have been waiting for the 838-IO Plus preorder to close.  I started rethinking this project a bit as I do not want to manufacture a new PEB enclosure.  So..  I have redesigned the board to fit in a ATX PC case.

 

The new board still features:

 

  • ATX Form Factor
    • It will mount directly up to a ATX case with the given standoffs.
    • Utilizes a 24 pin standard ATX power supply
      • 12v is ran to the 5v line of the TI cards, the voltage regulators will step it down to 5v as required.
    • Power Switch, Power LED and Reset Switch connections.
      • Note: Reset switch only works for the Geneve 9640.
    • 6 x 12v PC Fan connectors if you want to keep it cool!
    • Will utilizes the new 838-IO Plus Interface card.
      • Uses a small pigtail DB37 connector to connect from the current 838-IOP card to the vertical DB37 on the BUS board.  
      • Use the standard DB37 twisted paired cable from the TI to the new IOP connector that is exposed where the standard PC IO ports are.

I wanted to be able to create a mount for the Raspberry PI on the board to keep it in place, but with a MID tower that cannot be done as the PEB cards are just too long and flipping the cards 90 degrees will interfere with drive cages etc..

 

I have worked out a RPI mount that will bolt a raspberry into one of the 3.5 HDD drive bays or even a 3.5 floppy drive bay.

 

if users do not want to do that then I recommend to mount the TiPi into slot #8 as it should give the necessary clearance for the RPi, but I won't know for sure until I get the prototype boards ordered and in.  This is my plan to do next week when I order the 838-IOPs for all the preorders.

 

Here is a 3D rendered drawing.

838-PEB-ATX.png

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11 minutes ago, Shift838 said:

I had some time while I have been waiting for the 838-IO Plus preorder to close.  I started rethinking this project a bit as I do not want to manufacture a new PEB enclosure.  So..  I have redesigned the board to fit in a ATX PC case.

 

The new board still features:

 

  • ATX Form Factor
    • It will mount directly up to a ATX case with the given standoffs.
    • Utilizes a 24 pin standard ATX power supply
      • 12v is ran to the 5v line of the TI cards, the voltage regulators will step it down to 5v as required.
    • Power Switch, Power LED and Reset Switch connections.
      • Note: Reset switch only works for the Geneve 9640.
    • 6 x 12v PC Fan connectors if you want to keep it cool!
    • Will utilizes the new 838-IO Plus Interface card.
      • Uses a small pigtail DB37 connector to connect from the current 838-IOP card to the vertical DB37 on the BUS board.  
      • Use the standard DB37 twisted paired cable from the TI to the new IOP connector that is exposed where the standard PC IO ports are.

I wanted to be able to create a mount for the Raspberry PI on the board to keep it in place, but with a MID tower that cannot be done as the PEB cards are just too long and flipping the cards 90 degrees will interfere with drive cages etc..

 

I have worked out a RPI mount that will bolt a raspberry into one of the 3.5 HDD drive bays or even a 3.5 floppy drive bay.

 

if users do not want to do that then I recommend to mount the TiPi into slot #8 as it should give the necessary clearance for the RPi, but I won't know for sure until I get the prototype boards ordered and in.  This is my plan to do next week when I order the 838-IOPs for all the preorders.

 

Here is a 3D rendered drawing.

838-PEB-ATX.png

That's looks awesome. Can't wait to see a fully built unit.

 

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One thing I should mention is that many of the old cards have some very aging regulators and operate inefficiently and get very hot.  I have replaced all of my regulators with new 1.5 amp versions to ensure they operate at the best of their ability and I have measured heat from the regulators (old vs new) and have seen a dramatic decrease with the new 1.5 amp as they seem to run quite a bit cooler and more efficient power regulation.

 

I suggest that anyone that wants to go this route change out their regulators.  once I start taking orders I will include an option to buy new +5v and -12v regulators.

 

 

 

 

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34 minutes ago, Shift838 said:

One thing I should mention is that many of the old cards have some very aging regulators and operate inefficiently and get very hot.  I have replaced all of my regulators with new 1.5 amp versions to ensure they operate at the best of their ability and I have measured heat from the regulators (old vs new) and have seen a dramatic decrease with the new 1.5 amp as they seem to run quite a bit cooler and more efficient power regulation.

 

I suggest that anyone that wants to go this route change out their regulators.  once I start taking orders I will include an option to buy new +5v and -12v regulators.

 

 

 

 

Good suggestion as these old cards need all the help in extending their functionality as heat being the number one enemy towards any electronic component.

You still have to hand it to TI for building these system. The old PEB was manufactuered to military standards at least by today's standard. LOL.

 

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12 hours ago, GDMike said:

Do we need cards in protective containers or not?

There will be a card guide in place to help guide both shelled and unshelled cards inside the new system and it will provide 2 functions:

 

1. guide the cards into their slots

2. support of the cards since they will be mounted on their side.

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13 hours ago, rgjt said:

Good suggestion as these old cards need all the help in extending their functionality as heat being the number one enemy towards any electronic component.

You still have to hand it to TI for building these system. The old PEB was manufactuered to military standards at least by today's standard. LOL.

 

I would really like to see a horror move where someone takes PEB and takes care of the serial killer!  That sucker is heavy!

 

 

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9 minutes ago, Shift838 said:

I would really like to see a horror move where someone takes PEB and takes care of the serial killer!  That sucker is heavy!

 

 

For sure as it could also be used as a bunker busting bomb when dropped from a few feet.

It's a good measure to wear steel-toed work boots when handling that dead weight.:lol: 

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1 hour ago, rgjt said:

For sure as it could also be used as a bunker busting bomb when dropped from a few feet.

It's a good measure to wear steel-toed work boots when handling that dead weight.:lol: 

Your likely not to ever see anything built so well again for the rest of your kids'lives.

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a few fellow TI'ers have expressed interest to see a mockup.  Although I don't have the actual boards.  I do have the ATX Mid Tower case I have been working off of (Antec VSK4000E-U3).  I have mounted a 3.5 and 5.25 drive in the case.  Some carefully aligned paper prints and I have a rough mockup.  

 

Notice the TiPi with a raspberry pi mounted fits nicely in slot #8 with no issues for clearance, even with the 5.25 drive installed.

 

I did have to move the ATX power connector, 2 fans, 9640 reset, etc out of the way.  But now all looks good.

 

 

IMG_0379.JPG

IMG_0380.JPG

Edited by Shift838
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Chris,

 

What is the plan for the card guide?  Are you looking at sheet metal or 3D printing, or ????

 

Second question, and this is really late to the game.  I don't know if this is an option for the Geneve, but does the capability exist for a Geneve system to have more than 8 slots if it was bigger?  I know for the 4A, there was a limit with the interface card, but did not know if that issue existed for the Geneve.  I know there would be a very small market for such an option, but thought I would ask anyways.  If it was something you would even consider, then think "big" for the case so one can have a floppy drive, SCSI drive (SCS2SD or drives), DREM or hard drives.  Thinking here at least 4 accessible drive bays and maybe up to 6.

 

Just a thought.

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56 minutes ago, 9640News said:

Chris,

 

What is the plan for the card guide?  Are you looking at sheet metal or 3D printing, or ????

 

Second question, and this is really late to the game.  I don't know if this is an option for the Geneve, but does the capability exist for a Geneve system to have more than 8 slots if it was bigger?  I know for the 4A, there was a limit with the interface card, but did not know if that issue existed for the Geneve.  I know there would be a very small market for such an option, but thought I would ask anyways.  If it was something you would even consider, then think "big" for the case so one can have a floppy drive, SCSI drive (SCS2SD or drives), DREM or hard drives.  Thinking here at least 4 accessible drive bays and maybe up to 6.

 

Just a thought.

 

I'm thinking for the card guide a simple 3D printed guide to bolt into the same holes as the standoffs just with longer screws.

 

for your second question maybe @InsaneMultitasker could answer if it is even possible.

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