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TI-99/4a Modification Weekend.

mitsumi keyboard repair keyboard Reset Button Mod Tursis internal 32k mod

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#51 Sinphaltimus OFFLINE  

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Posted Sun Oct 23, 2016 3:43 AM

Note that so far, I have found four different brands with that power supply--so on your hunt, the only thing that is important is the part number, as the brand could be any one of many. . .


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#52 Sinphaltimus OFFLINE  

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Posted Sun Oct 23, 2016 3:45 AM

Pretty busy this weekend and next. So in about 2 weeks I'll be addressing this depending on what I can find out by then.

#53 schmitzi OFFLINE  

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Posted Sun Oct 23, 2016 4:17 AM

I don´t know if this is what you are looking for, but maybe it can help a little bit:

 

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Attached File  pebpowersupply.gif   23.2KB   1 downloads

 

(tags: PEB power supply)



#54 Sinphaltimus OFFLINE  

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Posted Sun Oct 23, 2016 4:38 AM

I completely removed this from the PEB. Went with an atz PSU and found it to be damaged after the install. 



#55 Sinphaltimus OFFLINE  

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Posted Mon Oct 24, 2016 10:08 AM

Browsing Facebook I came across a mod I had otherwise forgotten about. The alpha lock fix for joysticks.

I'm adding that to my long list.

Basically, my Frankenstein TI and PEB setup are my modding victims. I'm going to perform as many mods as i feel capable of to just these two devices.

However; it'll be at least 2 weeks before I go messing with anything. And at that time I'll be either repairing or replacing my atx psu in the peb.

And that brings me to my next question.

Right now, the faceplate of my PEB is connected to the main body via wires. The wires to my lcd displays and temperature probes and leds and switches etc.

I've been brain storming on my own the idea of splicing in a single connector to carry all the power and com wires.

Voltages are atx standard +5/gnd/-5/+12 so my concern is what I could use as the connector.

My initial thought was an ide cable but I don't think those thin wires will like the voltages. And I don't think the heavier gauge for power will work well for the lcd and temp probe wires.

Any ideas for a single connection or should I just consider two connections? One for power and one for coms?

Again, any suggestions on the type of connectors I should/could use?

I was even thinking if a scart cable would work as long as I had the male and female connections but again... The power....

Edited by Sinphaltimus, Mon Oct 24, 2016 10:10 AM.


#56 Sinphaltimus OFFLINE  

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Posted Sun Dec 4, 2016 5:42 AM

Yeah, it's been a while. But that's because I've been collecting parts for the next modification weekend hopefully coming up before the end of the year.

Here's what I have planned and some ideas I wanted to bounce off you folks.

F18A is in hand.

USB keyboard adaptor is on the way (I want to be able to connect this to a kvm and share3 KB with pc)

crystal speed up - need a proper micro switch, rest of parts are in hand.

nanopeb on the way - I really wanted the serial option for connecting to PC and possibility of getting it on-line just because. (it's a lot less expensive than a modified rs232 card alone)

 

However; I also want to do the internal speech synth modification. I just want to triple check with all of you that the internal speech synth mod is good for continued expansion on the side port including power (nanopeb).

This is the console I plan to incorporate in to my desktop PC workspace to no speech synth connected to the side port is a must for lack of space reasons but I do not want to lose the speech synth..

Then it occurred to me that I really don't need the console itself near me if I could incorporate the power switch, reset button and cartridge port into a USB keyboard then I really wouldn't need a kvm because essentially, for the console, I'd only be dealing with a keyboard and not a console plus kvm for desktop realty. At that point I could store the console on it's front side vertically (using a crafted base) and save even more space.

So naturally I have some basic questions in regards to the cartridge port. How long of an expansion is feasible without putting serious strain on the port? 
I'm thinking of using several keyboard cables as extension to carry the power switch, reset button and cartridge port connections to the usb keyboard. I can thread them together for aesthetics. 

Then I'd just need to mount the switch, button and cartridge port to the KB, some simple soldering and done.

Do ya'll think that the cart port would be OK with the added wiring?
What might I have to consider otherwise?
Are there concerns about running the TI at the faster 14mhz and using something like a nanopeb at the same time? What about the f18a?
I am aware that at 14mhz I could run in to baud rate issues using the serial port if the same issue exists like with the rs232 card as defined in the project description.

"John informed me that the RS232 card baud rate is dependent on the timing of

this crystal, which means you will end up with some weird baud rates being
generated. John has a fix for this and will be getting the information to me on
how to update the PROM on the TI RS232 card."


#57 atrax27407 OFFLINE  

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Posted Sun Dec 4, 2016 7:52 AM

It is not as easy as you think. You will need to change the clock frequency designated in the EVEN console ROM at byte 13 and re-compute the baudrates in the baudrate table in the RS232 DSR. I tried that project years ago but came up with mixed results using a 3.58mhz crystal. I would be interested to see the "fix". I suspect that the results would be much the same - some baudrates work and others don't. 



#58 Sinphaltimus OFFLINE  

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Posted Sun Dec 4, 2016 8:04 AM

I plan to make it switchable and only run the higher speed when using specific programs that could benefit from it. If it's going to be an issue with rs232, I'd just as well run the stock crystal when using it. I just don't want to get any sort of data corruption on the nano or damage the f18a in any way by running at the faster clock the few times I would.

Edited by Sinphaltimus, Sun Dec 4, 2016 8:05 AM.


#59 Ksarul OFFLINE  

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Posted Sun Dec 4, 2016 8:31 AM

I have a 12" (30CM) cable for the cartridge port to extend the connector outward. You can get these from the cable people that make the side port extension cables. 



#60 Sinphaltimus OFFLINE  

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Posted Sun Dec 4, 2016 5:45 PM

I have a 12" (30CM) cable for the cartridge port to extend the connector outward. You can get these from the cable people that make the side port extension cables. 


I take it you mean these guys?

http://www.cabledepo...5MCOlderTI.html
 



#61 Shift838 OFFLINE  

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Posted Sun Dec 4, 2016 6:11 PM

I take it you mean these guys?

http://www.cabledepo...5MCOlderTI.html
 

 

this place is usually quite a bit cheaper

 

HERE


Edited by Shift838, Sun Dec 4, 2016 6:14 PM.


#62 Ksarul OFFLINE  

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Posted Sun Dec 4, 2016 6:28 PM

Yes, that is the one I have. . .and both sites are selling products from the same source. . .here's the primary source.


Edited by Ksarul, Sun Dec 4, 2016 6:32 PM.


#63 Sinphaltimus OFFLINE  

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Posted Wed Dec 28, 2016 3:52 AM

My vacation is one long weekend to me and with Christmas out of the way and less than half my vacation remaining. It's time to get back to it.
 

Move speech synth internal to console.

Install F18A

Install USB keyboard adaptor.

I will update here when done with Photos and more. If we're friends on Facebook you'll get updates as I progress. If were' not friends on facebook, shoot me a private msg here and a friend request over there. https://www.facebook.com/SExmortus



#64 Sinphaltimus OFFLINE  

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Posted Wed Dec 28, 2016 2:16 PM

I only got to install my F18A today. Nothing drastic about it, pretty straight forward. So I really didn't take but 2 pictures that I'll post later.

 

Kind oif having an issue with it right now but I'm going to start a different thread for that or seek help in an F18A thread.


Edited by Sinphaltimus, Wed Dec 28, 2016 2:16 PM.


#65 Sinphaltimus OFFLINE  

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Posted Thu Dec 29, 2016 3:33 PM

Issues with my USB adapter left this project half baked. 

Once I get it resolved and get my GROM port extension cable, I'll be able to slide the TI all the way back and out of site under the shelf.

Yes, that keyboard is external to the TI. I plan to remove it as soon as I get my USB keyboard working and I won't have to remove a screw since I left the TI KB external.

 

PS - F18A rocks!

15676349_10207807943268509_7378340343246


Edited by Sinphaltimus, Thu Dec 29, 2016 3:34 PM.


#66 Sinphaltimus OFFLINE  

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Posted Sat Jan 14, 2017 4:32 PM

Woo hoo! Got my USB Keys operational. Now it's time to remove the TI KB and slide the console way back under that shelf. Picks soon or tomorrow or something.... :)

Huge shout out to Jedi Matt for having the patience of a Jedi and guiding me through the steps I needed to figure this out.



#67 Sinphaltimus OFFLINE  

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Posted Sat Jan 14, 2017 5:18 PM

15936981_10207930214925224_6205252574313

 

 

TI-99/4a hardware integration into PC workspace is completed as far as function goes. I still need to make things a bit more permanent and neat.

The goal for this project was to eliminate the need for me to get up off my seat and move over to another workstation in order to use or test things on the original TI hardware. I accomplished this my completing 3 goals. first was a shelf to slide the TI under a monitor. That was easy.

Next was to install a USB keyboard kit. I had to make an adaptor for it because of the installation method i wanted to use and my adaptor didn't work (scroll up and follow from the beginning). so getting that to work I was able to connect the TI to my PC keyboard via a USB based KVM switch box. Why? So I could slide the TI under the shelf making the console keyboard impossible to use. (Which is why I remove it).

The next challenge was the cartridge port. With the TI all the way under the shelf I wouldn't be able to access the cartridge port. So I had to purchase a GROM port extension cable. This gives me access to the carts without issue.

Next was actually a bonus. I wasn't planning to connect serial to serial as my console did not have an rs232 port but I did manage to score a nanPEB that does in fact have an RS232 port. So connecting PC to TI functionality added. This is a bonus 4th step.

So now I can develop on the PC, via serial null modem I can transfer files to virtual floppy drive (compact flash) on the TI's nanoPEB and almost immediately test the software right on real hardware from my PC keyboard. And I didn't lose and desktop real estate in doing so (a major goal for this project). The KVm is not in its final resting place at the moment.


Edited by Sinphaltimus, Sat Jan 14, 2017 5:18 PM.


#68 Sinphaltimus OFFLINE  

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Posted Sat Jan 14, 2017 6:00 PM

15937029_10207930333888198_5830803772489

 

 

Originally I wanted to mount the GROM port extension cable above the LEDS but instead I'm going to make a multi-cart expansion not connected to the KB at all.


Edited by Sinphaltimus, Sat Jan 14, 2017 6:02 PM.


#69 Sinphaltimus OFFLINE  

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Posted Sat May 13, 2017 1:48 PM

So my PEB has been out of commision due to the damaged resistor on the ATX power supply I posted about somewhere in the distant path. I finally got around to fixing it.

The original problem was part of the resistor broke off. The part with the first color band so it was impossible to identify exactly what resistor I needed to replace it. I left it attached and did a quick solder job. That seemed to work, for a little while. Then when the peb would warm up, it would shut off unexpectedly. I presumed a bad solder job and the connection would break, after it cooled a little it would work again, until it didn't anymore.

So i decided this weekend was the time to fix it.

I removed the resistor and discovered the damage in close up magnified detail.

 

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I had no choice but to either replace the entire psu (wasn't going to happen anytime soon) or salvage what was left of the resistor..
I decided to salvage it. So i soldered on some jumper wires...

 

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Then I had to find a way/place to solder on some pins to connect to. Close up photos of the back end showed the damage in more detail. I had to create more damage to come up with a plan.

 

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Identifying a yellow wire that was also soldered to one end gave me a path to follow so I proceeded to solder the pins as best i could given the tight working space...
 

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Then i connected the resistor....

 

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And fired up the PEB.

 

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FIXED!

Yes it's ugly. Yes it's not what a pro would have done, but I'm not a pro at this and I have to utilize what i can to do these kinds of things.
At least I can say - IT'S WORKING!

I went to go connect everything back up and utilized my PEB extension cable I purchased so as not to have the PEB connector on the side of the TI. unfortunately, I cannot locate my home made A/V cable so now I have to make another. I'll probably do that (or just purchase one) sometime this week to confirm all is in good order and my peb will no longer shut off on its own.

 

 

 



#70 sparkdrummer OFFLINE  

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Posted Sat May 13, 2017 1:51 PM

Necessity is the mother of invention. I say well done Lenny.

#71 Ksarul OFFLINE  

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Posted Sat May 13, 2017 3:07 PM

I would suggest using an ohm meter to read the value of that reistor before it cooks some more. . .at least then, you'll know a little more about what its value should be.



#72 Sinphaltimus OFFLINE  

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Posted Sat May 13, 2017 6:37 PM

I would suggest using an ohm meter to read the value of that reistor before it cooks some more. . .at least then, you'll know a little more about what its value should be.

Holy DUH! I was so happy to have the peb working again it never occurred to me. I'll open it up again tomorrow.



#73 Sinphaltimus OFFLINE  

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Posted Sun May 14, 2017 12:02 PM

Holy DUH! I was so happy to have the peb working again it never occurred to me. I'll open it up again tomorrow.

 

So, I want to make sure I got this right. Set my MultiMeter to Ohms, turn on the peb, measure from both sides of the resistor. I get 0.025. So that would mean a 25k Ohm pull up resistor?



#74 Stuart OFFLINE  

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Posted Sun May 14, 2017 4:47 PM

 

So, I want to make sure I got this right. Set my MultiMeter to Ohms, turn on the peb, measure from both sides of the resistor. I get 0.025. So that would mean a 25k Ohm pull up resistor?

 

No, you need to measure it out of circuit. Switch off the PEB, pull the resistor wires off those two pins you added, and measure across the resistor with it not connected to anything.



#75 Sinphaltimus OFFLINE  

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Posted Sun May 14, 2017 5:20 PM

 

No, you need to measure it out of circuit. Switch off the PEB, pull the resistor wires off those two pins you added, and measure across the resistor with it not connected to anything.

 

Ah OK, I'll try that tomorrow.







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