NEO-CDA board: Difference between revisions

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Audio/video and power boards in CD2 models.
The audio/video and power boards in top-loading NeoGeo CD consoles.


= NEO-CDA3-1 =
The version for the front-loading console is [[CD-ANA-2_board|CD-ANA-2]].
[[File:Neo-cda3-1.png|thumb|NEO-CDA3-1 power supply zone schematic]]


=NEO-CDA3-1=
[[File:Neocda31.jpg]]
[[File:Neocda31.jpg]]


Carries a [[YM3016]] DAC, [[LC78815]] CDDA DAC, 2 quad op-amps, a [[CXA1645]] video encoder, 2 7805 regulators, a LM2930 8V regulator and various transistors.
Carries a {{Chipname|YM3016}} DAC, [[LC78815]] CDDA DAC, 2 quad op-amps, a [[CXA1645]] video encoder, 2 7805 regulators, a LM2930 8V regulator and various transistors.


Connectors, from left to right (need exact pinouts):
Connectors, from left to right (need exact pinouts):
Line 14: Line 14:
*CD 5V, 10V CD, 5V logic, Ground
*CD 5V, 10V CD, 5V logic, Ground


= NEO-CDA4-1 =
=NEO-CDA4-1=


[[File:Neocda41.jpg]]
[[File:Neocda41.jpg]]


Same as the NEO-CDA3-1, but with only one dual op-amp and a second [[LC78815]] instead of the [[YM3016]] (which isn't needed anymore with boards using the [[NEO-YSA]] chip, capable of outputting LC78815 compatible serial streams).
Same as the NEO-CDA3-1, but with only one dual op-amp and a second [[LC78815]] instead of the [[YM3016]] (which isn't needed anymore with boards using the {{Chipname|NEO-YSA}} chip, capable of outputting LC78815-compatible data).


24M08 regulator instead of the LM2930 ?
24M08 regulator instead of the LM2930 ?
Line 28: Line 28:
*CD 5V, 10V CD, 5V logic, Ground
*CD 5V, 10V CD, 5V logic, Ground


[[Category:CD systems]]
=Power supply circuit=
 
Circuits for both versions of the board seem to be identical.
 
[[File:Neo-cda3-1.png]]
 
Both +5V and +10V supply voltages are limited to 5V and 11.4V by means of a pair of (strange) protection circuits made of transistors to bring the voltage down by dissipating heat through resistors R15 and R18 if needed. The +5V input is used to power the main board. The +10V input is used to power the CD drive, and 3 linear regulators for the op-amps and audio DACs.
 
A thermal fuse (one-time use ?) is coupled to Q3 with a blob of silicone, preventing the console from being turned on again if excessive heat was generated.
 
[[Category:Repairs]]
[[Category:Chips]]
[[Category:Chips]]

Latest revision as of 06:51, 12 August 2018

The audio/video and power boards in top-loading NeoGeo CD consoles.

The version for the front-loading console is CD-ANA-2.

NEO-CDA3-1

File:Neocda31.jpg

Carries a YM3016 DAC, LC78815 CDDA DAC, 2 quad op-amps, a CXA1645 video encoder, 2 7805 regulators, a LM2930 8V regulator and various transistors.

Connectors, from left to right (need exact pinouts):

  • YM2610 to YM3016 serial data
  • CDDA left, right, clock
  • RGB video and sync
  • CD 5V, 10V CD, 5V logic, Ground

NEO-CDA4-1

File:Neocda41.jpg

Same as the NEO-CDA3-1, but with only one dual op-amp and a second LC78815 instead of the YM3016 (which isn't needed anymore with boards using the NEO-YSA chip, capable of outputting LC78815-compatible data).

24M08 regulator instead of the LM2930 ?

Connectors, from left to right (need exact pinouts):

  • CDDA left, right, clock
  • NEO-YSA left, right, clock
  • RGB video and sync
  • CD 5V, 10V CD, 5V logic, Ground

Power supply circuit

Circuits for both versions of the board seem to be identical.

File:Neo-cda3-1.png

Both +5V and +10V supply voltages are limited to 5V and 11.4V by means of a pair of (strange) protection circuits made of transistors to bring the voltage down by dissipating heat through resistors R15 and R18 if needed. The +5V input is used to power the main board. The +10V input is used to power the CD drive, and 3 linear regulators for the op-amps and audio DACs.

A thermal fuse (one-time use ?) is coupled to Q3 with a blob of silicone, preventing the console from being turned on again if excessive heat was generated.