No pic No Sound help this fool! :)

[Mehridian Sanders]

Just hooked up my newish TI-99/4a to an atx power supply. Bypassed the power board and fed it straight into the mainboard. I carefully placed the 12v, 5v, -5v, and the gnd cables as they were fed from the power board. I got power from the supply flowing and the av out went to a vizio TV av cable. Got no sound no pic. Pictures to follow shortly.

 

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[Mehridian Sanders]

Here we go

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[Mehridian Sanders]

Better pics and connections:
◇Main pin 14 connected to Main pin 15
◇Yellow wire from atx main pin 10 (12v)
To TI mainboard ○●○○
◇Red wire from Main pin 20 (5v) to TI mainboard ○○○●
◇Black wire from Main pin 7 (GND) to TI mainboard ○○●○
◇White wire from Main pin 18 (-5v) to TI mainboard ●○○○



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[Mehridian Sanders]

Sega genesis replacement adapter connections (while looking at the Male end)
left to right.
1-NC
2-Audio Out
3-GND for Audio and Video
4-NC
5-Video Out

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[Mehridian Sanders]

Apparently it helps when you plug the Audio out into the Audio instead if the video..

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[wierd_w]

Excellent!  This means a simple breakout board for a picoATX (20pin!! NO 24 pin!!) would work great with a Ti 99/A4.

 

That would fit neatly inside the case. (PicoATX is smaller than the original power board.)

[Mehridian Sanders]

It would work perfectly. I took your suggestion and found that old ATX 1 I had.

Demo Link... don't judge too harshly. Playing 1 handed while filming.

http://imgur.com/gallery/O2TrJOE


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[wierd_w]

External ATX is unelegant, but is a good showing that the signals will work fine. PicoATX is a mass produced consumer product, and a breakout board would be cheap to manufacture.

[tater1337]

7 hours ago, wierd_w said:

External ATX is unelegant, but is a good showing that the signals will work fine. PicoATX is a mass produced consumer product, and a breakout board would be cheap to manufacture.

is there a thread here about Pico ATXconversion?

[wierd_w]

No, I only recently mentioned it in the "PSU replacement?" Thread.  I cited what pins in the 20 pin header you need, and what they go to.

 

I am kinda surprised that the community designs custom VDUs, but there's no PicoATX breakout. It should be a drop in replacement with such a board. (Shrug)

[Mehridian Sanders]

1 hour ago, tater1337 said:

is there a thread here about Pico ATXconversion?

It's surprisingly easy. I had my doubts at first but after taking a leap of faith ... works just fine. 

 

8 hours ago, wierd_w said:

External ATX is unelegant, but is a good showing that the signals will work fine. PicoATX is a mass produced consumer product, and a breakout board would be cheap to manufacture.

I agree. It is. With the removal of the original power board, there is a LOT of space right up front. In truth, there is a lot of space in there, in general. 

[Mehridian Sanders]

Oh for anyone trying to get a replacement AV cable. I bought mine at a brick and mortar store. Sega Genesis Replacement cable. I think I paid $8 for it.

 

Here is a link to a cheaper one : https://www.amazon.com/Mizar-Replacement-Sega-Genesis-Standard-Cable/dp/B002FY0CM0?th=1

 

[GDMike]

I suppose the heat loss is min.

[wierd_w]

Upon further reading, I seem to find that pretty much every PicoATX (even the 20 pin versions) do not provide the -5v rail, because they consider it to be a legacy feature that nobody needs.

 

That means that a breakout board for one will need one of these baked into it to provide the missing -5v rail.  Should still be inexpensive though.

[+arcadeshopper]

or use this: https://www.digikey.com/product-detail/en/mean-well-usa-inc/GP25A13A-R1B/1866-1825-ND/7703336