🇺🇸 Texas Instruments TI 99/4A: Part 4 (PAL RGB Video Mod) [TCE #0536]
32Next, let's try converting this Aussie TI 99/4A's PAL component (Y/Pb/Pr) video output to RGB by using the TMS-RGB board (designed for the TMS9928A and TMS9929A VDPs). Whilst I have the machine apart, I also use a thermal imaging camera to check the hot spots on the board.
The RGB mod. is relatively simple - we can re-use the existing 6-pin DIN video connector, keeping the GND and Audio pins and routing the new R/G/B/S signals to the other four.
To isolate the four pins we'll be re-using I removed a total of five components:
Pin 1: was 12V, now RED, removed a resistor and capacitor
Pin 2: was Y, now GREEN, removed link wire
Pin 3: was Pr/Ry, now BLUE, removed link wire
Pin 4: was Pb/By, now SYNC, removed resistor
Pin 5: remains AUDIO
Pin 6: remains GND
Part 3:
• 🇺🇸 Texas Instruments TI 99/4A: Part 3...
00:00 ... Start
01:25 ... Current component video output
02:10 ... Proposed RGBS pinout
05:55 ... TMS-RGB board soldered on
07:00 ... New RGBS signal wires soldered on
07:14 ... Making the 6-pin DIN cable for RGBS + Audio
15:05 ... Cable completed ... not too happy with it but it'll work
15:50 ... Video capture setup
17:25 ... Testing the RGB output
18:30 ... Sunrise over Cowra & Patreon ad
19:00 ... Refurbishing power supply (replacing linear regulators & LED)
24:00 ... Trying some games with the FinalGROM99
25:05 ... Burgertime
26:30 ... Pyjamarama
28:45 ... Checking heat with thermal imager
30:17 ... Channel outro/thanks
TMS-RGB board:
hhttps://tms-rgb.com/
Alternate power supplies (from Part 1 video):
[1] A replacement power supply that generates the DC voltages directly and has the correct plug. You will need to modify the internal power board to bypass itself totally:
hhttps://www.keelog.com/power-supply/#ti99
[2] Replace the internal power board with something like this that only requires a regulated 12VDC power supply. You can either replace the power socket with a 2.1mm socket or cannibalise the original plug:
hhttps://github.com/dabonetn/ti99psu-replacement
[3] Use a Mean Well GP25A13A-R1B as the power supply and remove the internal PSU board, wiring a 5-pin DIN socket to the internal cabling.
--------------------------------
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you don't think it's worth it, then cancel ... no hard feelings ... I appreciate any support, even if it's just subscribing to my YouTube channel!
https://www.patreon.com/TheCluelessEngineer--------------------------------
Music by Karl Casey @ White Bat Audio
hhttps://karlcasey.bandcamp.com/ / @whitebataudio