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11 hours ago, J-Data said:

SMT soldering isn't that bad, just need patience and some good flux

Nicely done!  One thing that you might want to correct is the VGA connector.  When the pins are fully pushed through the PCB, you don't get enough clearance for the cable.  It might be okay with yours, but I have started to only put the pins into the board so that they are flush to the underside, giving me more space in the machine.

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On 3/30/2021 at 7:56 AM, Hans23 said:

One thing that you might want to correct is the VGA connector.  When the pins are fully pushed through the PCB, you don't get enough clearance for the cable.

Good idea.  Took a little doing with a heat gun, but its much higher now.  

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On 3/29/2021 at 7:45 PM, J-Data said:

Slow progress, but almost there.  SMT soldering isn't that bad, just need patience and some good flux.  Only part I couldn't get from distribution was the NOR SPI Flash.  Still have a couple of extra bare boards if anyone wants one.

 

 

Wheni built mine I used the below NOR SPI Flash IC.

 

https://www.digikey.com/product-detail/en/winbond-electronics/W25Q80DVSSIG/W25Q80DVSSIG-ND/4836572

 

 

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I've put Matthew's BOM into a Google Sheet.

 

I can report that I've sent out 15 F18A's at this point.  Some have been received and and installed.  A few people have not received their board yet, but even after the current list is empty, I still have parts and PCBs left.  If you're interested in getting a board in May or June, put yourself onto the list

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4 hours ago, Hans23 said:

I've put Matthew's BOM into a Google Sheet.

 

I can report that I've sent out 15 F18A's at this point.  Some have been received and and installed.  A few people have not received their board yet, but even after the current list is empty, I still have parts and PCBs left.  If you're interested in getting a board in May or June, put yourself onto the list

What is the approximate cost?

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2 hours ago, broettger said:

What is the approximate cost?

The cost of the parts runs down at about $50.  I need an hour to build a board.  I'm leaving it up to everyone to make a sensible bid.

 

-Hans

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I have been asked whether I include printed installation instructions with the F18A boards that I might - I do not, and that could certainly be a problem to the less electronics savvy.  The process is straightforward, but it requires opening the console and routing the cable outside of the case requires some creativity.  If you've never opened your TI-99/4A, here is a guide that describes the process.

 

Once you're in, you need to locate the TMS9918A (or TMS9929A) VDP chip and remove it.  The chip is the 40 pin chip covered with white termal paste.  Here is a video that almost shows how to remove it from its socket - Almost because the person in the video only lifts the chip from one end, bending the two pins on the other end.  Instead, lever the chip out with a small screwdriver from both sides, in an incremental fashion.

 

Install the VGA cable on the F18A - There is a bump on the cable that needs to face down when it is plugged into the pin header on the board.  Then install the F18A in the VDP socket with the "PIN1" pointing to the center of the motherboard.  Due to the other neighboring components on the board, there is only one way to plug in the F18A, the cable connection will run over the neighboring 40pin chip.  Make sure that you firmly press on the F18A board so that the pins completely go into the socket.

 

If you want to reinstall the RF shield, you'll want to remove the small aluminum block that is mounted opposite to the VDP on the upper part of the shield.  If you want to mount the VGA plug permanently on the back of the machine, you'll need to make a cutout in the RF shield that allows you to install and remove the VGA cable when the RF shield is installed.  I leave the RF shield off, which makes things easier.  Remember, however, that the VGA cable restricts how far you can flip the motherboard over, you'll have to be careful lifting the motherboard once the cable is installed.  Also, the cable is a rather tight fit, so you way want to make the cutout in the RF shield large enough to allow you removing the F18A from the board without taking off the heat shield.

 

I put a warning label "F18A installed" on the bottom of my motherboard to remind me to be careful when lifting it up.

 

Please let me know if you need further installation help with the boards that I've built.  I'd also appreciate if we could see some photos by people who have installed theirs for inspiration.  I'm away from my workshop for a few days so it will take me a bit before I can provide photos of my installaion. 

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Posted (edited)

The only issue I might have is that my soldering skills are lacklustre from years of pounding on keyboards. (Carpal tunnel is a bitch.)  As such, I would like to install a chip socket in place of the VDP, and then install the F18A on the socket, but I hear the F18A is fairly tall, and that this is a dubious prospect.

 

If I am wrong on that, and I can totally get away with a socket, I would prefer to go that route to avoid putting lots of heat on the F18A's legs.

 

(Then again, I recently managed to pull off some delicate surgery to install a chipset fan inside a chromebook, by tapping the voltage rail from one of the USB ports without destroying the port... So maybe I am getting better?  I might be able to not ruin the F18A when installing it...)

Edited by wierd_w

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20210401_150633.thumb.jpg.4a82d72e7b48741d5948d7b1ab4ca482.jpg

 

Thanks Hans,

As many have said over the years, this is a super easy install.  I had no issues.  Also as others have said, it's glorious to see after all these decades.  Thanks to Matt and Hans for supporting this ancient computer

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59 minutes ago, wierd_w said:

I would like to install a chip socket in place of the VDP, and then install the F18A on the socket

TI already has you covered:  The VDP is in a socket (at least in all machines that I have seen), so all it takes is pull the TMS99(18|29)A and put in the F18A - No soldering is required.

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I picked up a bare board from J-data (thanks by the way) and intend to try it out sometime in the near future. My TI99 has suffered a port failure the 9901. I have removed the chip and am waiting for a replacement chip. I had intended to install a socket for the new chip. My question is, looking at some of the pictures of this F18A board, it appears that header pins come out over the 9901 chip. If I install a socket for the 9901 will that interfere with the F18A connection? Thanks Mike

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Posted (edited)
1 hour ago, mike_z said:

I picked up a bare board from J-data (thanks by the way) and intend to try it out sometime in the near future. My TI99 has suffered a port failure the 9901. I have removed the chip and am waiting for a replacement chip. I had intended to install a socket for the new chip. My question is, looking at some of the pictures of this F18A board, it appears that header pins come out over the 9901 chip. If I install a socket for the 9901 will that interfere with the F18A connection? Thanks Mike

No alot of TI's have socketed 9901's, from the factory.

Edited by RickyDean
spelling

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40 minutes ago, RickyDean said:

No alot of TI's have socketed 9901's, from the factory.

How common is that? None of my consoles do... in fact I started a 9901 replacement years ago and dropped it because I'd not seen a socketed one...

 

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Well your probably right. I do have 4 or 5 boards that have sockets, and I may have made that happen 20+ years ago, so mine may be the "lot". Sorry.

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Any chance of getting a kit that I can build myself? I'm set up to do soldering of just about any kind (my skill level is a different matter entirely, but I manage). 

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3 hours ago, RickyDean said:

No alot of TI's have socketed 9901's, from the factory.

I have take this back. The socketed ones are ones I did long ago and to use the f18a, you have to stack another socket at the video chip. So it can be done, but may not fit in the case or be stable. It does work though on a board outsid ed of a case. Sorry for the confusion.

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5 hours ago, mike_z said:

If I install a socket for the 9901 will that interfere with the F18A connection?

If you use pin headers like the below with your F18A, you'll be able to get enough clearance to make it sit above the socketed TMS9901.  The Mill-Max pins that I use are too short for that.  They're chosen to make the F18A fit into the machine with the RF shield installed.  Without it, there is enough room in the console to fit the higher construction, and it is probably also better in terms of getting the heat out.

 

image.thumb.png.ee4d4a142c83035344df5c45b3f2aa26.png

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10 hours ago, Hans23 said:

If you use pin headers like the below with your F18A, you'll be able to get enough clearance to make it sit above the socketed TMS9901.  The Mill-Max pins that I use are too short for that.  They're chosen to make the F18A fit into the machine with the RF shield installed.  Without it, there is enough room in the console to fit the higher construction, and it is probably also better in terms of getting the heat out.

 

image.thumb.png.ee4d4a142c83035344df5c45b3f2aa26.png

Yeah, these are my go-to pins for a lot of projects. . .

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On 4/7/2021 at 11:33 PM, rootboy said:

Any chance of getting a kit that I can build myself?

You can get everything but the PCB and the VGA cable at DigiKey, so that may be the closest thing to a kit out there.   I still have a bare board up for grabs, or for $7 you can order you own and have 4 left over to share. 

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2 hours ago, J-Data said:

You can get everything but the PCB and the VGA cable at DigiKey, so that may be the closest thing to a kit out there.   I still have a bare board up for grabs, or for $7 you can order you own and have 4 left over to share. 

Of course, you could also be a crazy person like me that probably has 5-10 systems I would want to put one in. . .LOLOL I may need to do that, as I need to polish up my surface-mount soldering skills.

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Hans,

 

I got my F18 installed, and it is up and running.  Many thanks!

 

Beery

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4 hours ago, J-Data said:

You can get everything but the PCB and the VGA cable at DigiKey, so that may be the closest thing to a kit out there.   I still have a bare board up for grabs, or for $7 you can order you own and have 4 left over to share. 

Thanks, but the boards aren't the issue, it's avoiding BOM hell. :)  And I'd love to have someone share their Digikey BOM with me if they've built one up because I'm not having a bunch of luck sourcing the parts on my own...

 

I'll just wait a bit longer for the Mk2 to come out, but thank you anyways.

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