Sound fix diagram here. (pdf)

from Cristian Secară Homepage:

The first release (the +3) has a fatal hardware mistake: the 128K sound output is completely distorted.

• Tech explanation: the analog output of the AY-3-8912 sound chip was intended to be amplified by a one stage common-emitter transistor. In practice, they have forgot to put a resistor to the transistor’s emitter. The result: the transistor works in switch-mode – the sound is converted from analog multi-level amplitude to digitized two-level amplitude, same as the old 48K sound system.

source: secarica.ro ay8912 Demos

ColecoVision RGB Hack:

Photo from #3 to #6 explain how to hack the RGB output signal inside the console.

ColecoVision RGB connector pinout:

__________________________________
\ o1  o   o3  o   o5  o   o   o8 /
 \  o   o   o   o   o13 o   o15 /
  \____________________________/

Pin Signal

 1  Red Output
 3  Green Output
 5  Blue Output
 8  Ground
13  Composite Synch
15  Audio Output (very low volume)

Scart RGB pinout:

   ----------------------------21
  _| 19 17 15 13 11 9 7 5 3 1 |
 |                            |
 | 20 18 16 14 12 10 8 6 4 2  |
  ----------------------------

Pin Signal                     Signal level

 1  Right Audio Out
 2  Right Audio In
 3  Left Audio In
 4  Audio Ground
 5  Ground (blue)
 6  Left Audio Out
 7  Blue input                 (0.7V, 75ohm)
 8  Function select/AV control (9.5-12V = AV mode, >10kohm)
 9  Ground (green)
10  Reserved Data
11  Green input                (0.7V, 75ohm)
12  Reserved Data
13  Ground (red)
14  RGB Blanking
15  Red input                  (0.7V, 75ohm)
16  RGB switching control      (1-3V = RGB mode on, 75ohm)
17  Ground (sync signal)
18  Ground (RGB switching)
19  Composite Out
20  Composite Input (Synch)    (as in 1Vpp video signal, 75ohm)
21  Common ground (shield)

Fix:

• Video Contrast problems: i have bypassed the resistor for RGB. (Photo #6)
• Jamma Connector is too big for my SNK MV-2F MVS: I have used a rasp for reduce the Jamma connector. (Photo #7)

source: wikipedia

The CheapLPC is a flashrom burner for the SST49LF020 chip, The Software can read back, and verify the contents of the chip.

The software is also compatible with any other CheapLPC based programmer, like that used in the Martrix by Xodus, Ozx Prog by OZx Modchips, Neurosys, and a few others.

Download: GreenProg (CheapLPC Programmer) v0.7 (1280)

source: wikipedia cheaplpc.com

Here’s the Pong in a chip from Polistil (1979) with the Famous chip TMS1965 (GI AY-3-8500 pins compatibile) from Texas Instruments.

have added a Composite Video / Audio output  intested of VHF antenna output.

wiki: Pong-Wiki

My homebrew UV Eprom Eraser. I have spent 8 euros for electrical components and 3 euro for the box.

Gallery: