NEO-CDA board: Difference between revisions
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The audio/video and power boards in top-loading NeoGeo CD consoles. | |||
The version for the front-loading console is [[CD-ANA-2_board|CD-ANA-2]]. | |||
[[ | |||
=NEO-CDA3-1= | |||
[[File:Neocda31.jpg]] | [[File:Neocda31.jpg]] | ||
Carries a | 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 | 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: | =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
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
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.
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.