Nintendo NES-101

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Top Loading NES, model NES-101

Released around the same time as the Super Nintendo, the top loading NES addressed some of the design oversights of the front loading NES, and introduced it's own set of minor complaints:

  • Benefits:
    • Non-ZIF pin connector eliminates most connection issues of the Front Loading NES
    • CIC chip removed, preventing endless reboot loops
  • Drawbacks:
    • Lack of A/V output (for all but a few even rarer NES-101 units with factory A/V multi-out)
    • Visible vertical lines in video signal
    • Powerpak uses pin 54 for FDS audio, which is not present in the toploader connector.


Regarding the missing pins, a Toploader 72-pin connector only has 68 pins populated, from:

  • 1 - 17
  • 20 - 53
  • 56 - 72


Chip Info

NESN-CPU-01 (1993)


NESN-CPU-JI0-01 (1993)


NESN-CPU-AV-01 (1994)


Capacitor Map

NESN-CPU-01

Purchase these parts as a kit

Toploader-NES-101-Cap-Map.png
C1	100uf	6.3v
C3	1uf	50v
C11	.47uf	50v
C13	1500uf	25v - The PCB screen says 1000uf,
                      but I've only seen 1500uf parts installed
C14	1uf	50v


A/V Modification

Purchase these parts as a kit

NES Toploader AV Schematic.png
Pinout for 2SA933 - E C B

Nintendo decided to drop the A/V jacks on the Toploader, probably as a cost saving measure. Fortunately, with a bit of time and the right parts, you can add your own A/V jacks!

Note: This modification disables the RF output, so you won't be able to use a modified toploader on a TV that lacks A/V inputs.


Video Parts List

    • Q1: 2SA933 / 931 / 937 / 1037, or equivalent
    • R1: 110ohm
    • R2: 300ohm
    • C1: 220uF, 6.3v
    • RCA Jack

Assemble components as shown. Desolder and/or clip PPU pin 21 and lift. If you leave pin 21 connected the output will have visible vertical lines. Optionally, if you want to re-enable RF, connect the pad for pin 21 to the output of the circuit. Be sure to do an A/B comparison on your monitor, but our tests show that the Composite output will be mostly unaffected.

The preferred location for the RCA jacks is to install on the upper case rear, where the Nintendo Service sticker is located. Remove the sticker and mark the drill locations for your jacks, paying attention to the location of the heat sink. You want to be sure that your holes are drilled so that the jacks do not contact the heat sink when reassembling the case.


Audio Parts List

    • C1 / C2: 1uf, 6.3v
    • 1 or 2 RCA Jacks

Mono mod: Connect the negative leg of your cap to the leg of either R6 or R7 that is farther from the CPU. Connect the positive leg to your audio jack.

Stereo mod: Connect the negative leg of your caps to the legs of either R6 or R7 that is closest to the CPU, or to CPU pins 1 and 2. Connect the positive legs to your audio jacks.


Troubleshooting

Image streaks to the side
Check for reversed emitter / collector