Sharp MZ-721

The Sharp MZ-700 series was launched in 1982.

model: MZ-721

Serial number: 35013657

data recorder: MZ-1T01

plotter: MZ-1P01

  • cpu: Z80A @ 3.5 MHz
  • ROM: 4K (+ 2K character gen)
  • RAM: 64K (+ 4K video RAM)
  • video out: composite video RF (UHF ch. 36, PAL) RGB

RGB connector 8-pin DIN

pin signal
6 Red
7 Green
8 Blue

screen size: 40 chars x 25 lines

colors: 8 (8 colors for background, 8 colors for characters)

power: 240 / 220 V AC, 50 / 60 Hz, plug is "sideways eight" (aka "infinity sign")


Sharp MZ on Wikipedia,, forum, PC tape interface, Sharp Users Club, The MZ corner, MZ-800 Service manual, MZFTools, Github SHARPENTIERS, orignal links: MZ-700 datasheets and manuals, Repairing PSUs,

more links

MZ-700 connectors, new MZ-700 connectors, MZ-700 Monitor 1Z-013A, DFRobot: Arduino LCD KeyPad Shield, JustRadios - Capacitor unit conversion chart, ORIC RGB Socket pinout ++,



other links uMZix - an UNIX for Sharp MZ-800, mz800em - Sharp MZ-800emulator, CircuitsToday: Arduino Mega 2560 pinouts and tutorial,

modern video output

GBS-8200, OSSC, Classic Console Upscaler wiki: OSSC wiki page,

monitor: L - loads file from tape

BASIC: LOAD - loads program from tape, BYE - exit to monitor


2019-08-29: backplane - the 2 x 5pc connectors from AliExpress arrived in my mailbox.

2019-08-12: parts - for backplane - 50 pin (2 x 25p) connector from AliExpress: 50 Pcs 2.54mm Pitch 2x25 Pin(4-120p) Stright IDC Box Connector Headers 50 Pins,

2019-08-11: parts - for adapter between mz-700 expansion and mz-800 expansion card - connectors, I ordered from AliExpress 50 pin - 2 x 5pcs Edge Connector Slot 2.54 mm Pitch 8 10 12 14 16 20 22 24 26 30 36 44 50 60 62 64 72 Pin PCB Gold Finger Socket Right Angle, High quality 50-Pin Connector Game Cartridge Slot for Nintendo 64 for N64 clone Console,

2019-06-19: expansion bus connector for MZ-700 (thread): 50 pin (2 x25 pin) IDC from eBay: 5pc Industrial Card Edge Slot Socket Connector 25x2P 50P 2.54mm 0.1" Right Angle, AliExpress: 50 Pcs 2.54mm Pitch 2x25 Pin(4-120p) Stright IDC Box Connector Headers 50 Pins,

2019-04-02: mz-sd2cmt - testing. Yes, I can load basic (1Z-013B) and other files. Nice!

2019-04-02: mz-sd2cmt - pins should be

MZ-700 Arduino
P-12 Mega2560
4 16
5 18
7 15
8 2

connect it up to the MZ-721.

2019-04-02: psu - I put the psu back into the machine and did a power-on test. The monitor comes right up. Good.

2019-04-02: mz-sd2cmt (and hlide's mz-sd2cmt): it seems that pin 2 on the Mega 2560 should be used instead of pin 3. Also see PinMapping2560.

2019-02-25: DIN plugs - yes, the DIN plugs I got fit the RGB DIN connector. Nice!

2019-01-17: eBay - the package with the DIN plugs arrived.

2019-01-08: Tape connector pinout - I checked my manual, the schematic for the machine confirms the P-12 layout:

  • 1 ex write
  • 2 ex read
  • 3 GND
  • 4 motor
  • 5 sense
  • 6 + 5V
  • 7 write
  • 8 read
  • 9 GND

this corresponds to the CNW3001 plug in the MZ1-T01 tape unit:

  • 4 remote
  • 5 sense
  • 6 + 5V
  • 7 write
  • 8 read
  • 9 GND

2019-01-08: eBay - ordered some DIN (aka DIN45322) connectors on eBay. The eight-pin 270 degrees will hopefully fit the MZ-721.

2018-12-31: eBay - the package with the SCART to HDMI Video Converter (1 x TPX Monitor Box Scart / HDMI to HDMI Video Converter) arrived in my mailbox. Power adapter model JK-0510, input 100 - 240 VAC 50 / 60 Hz. Output 5 V DC 1A, center positive. The converter itself look exactly like the one on the forum.

2018-12-27: eBay - the packet with the 0.01 microFarad capacitors showed up in my mailbox today.

2018-12-21: psu - I soldered in the new capacitor C2 (0.047 microFarad) that I got yesterday. The new one is only 10 mm between leads, so one lead is a bit exposed on PCB topside. No worries, the PSU is in an enclosure after all. Tested output voltage again, still 5.04 V.

2018-12-20: eBay - the packet with the 0.047 microFarad capacitors showed up in my mailbox today. That's only 8 days since they were shipped.

2018-12-19: LCD Keypad shield - I got 2 x Arduino LCD Keypad Shield in the mail yesterday. Now testing - they work. The RP1 trimpot is multi-turn, I have to adjust it quite a few turns before I can see the text on the display.

2018-12-13: video converter - I ordered 1 x GBS-8200 board on eBay, price was USD 16.75 shipping included. I also ordered (on eBay) 1 x TPX Monitor Box Scart / HDMI to HDMI Video Converter, price was USD 22.55 shipping included.

2018-12-11: psu - it is capacitor C2 (0.047 microFarad AC 250V) that is broken. This is a filter capacitor ("class X"), I need to find a replacement. 0.047 microF = 47 nF = 47000 pF. About 18mm wide, 15 mm between leads. Ordered from eBay, I also ordered some 0.01 microF. It will probably take about four weeks for the package to arrive. I reassembled the PSU without C2 for now, and measured the output voltage (unloaded): 5.04 V.

2018-12-10: psu - the PSU suddenly gave a pop and then smoke, so a least one capacitor blown. Time to repair that power supply.

2018-12-10: re-tested the MZ-SD2CMT, with correct pins

MZ-700 Arduino
P-12 Mega2560
4 16
5 18
7 15
8 3

but still the same problems; the monitor just shows the "press play" message, and the MZ-SD2CMT display just shows "Playing" messages. Nothing more happens. Replaced the jumper wires from the Mega2560 to the MZ-700, didn't help. Tried different .mzt files, didn't help.

2018-12-09: Ok, Read (MZT_DO) needs to use pin 3 (PE5/INT5/OC3) is it is the output of the oneshot configured at Timer3.

2018-12-08: Maybe I should test with the MZ-1T01 to see if it still works. OK, I found the tapes and mounted back the tape player. After a bit of fiddling it works (it is old, maybe the rubber belts are worn), and I could load BASIC from the Basic tape. It takes some minutes.

2018-12-08: MZ-700 P-12 pinout:

  • 1 (external write)
  • 2 (external read)
  • 3 GND
  • 4 motor / remote
  • 5 Sense
  • 6 + 5V
  • 7 Write
  • 8 Read
  • 9 GND

connections to the Mega2560

P-12 Mega2560
4 Motor - SSI 16 MZT_MI
5 Sense - SSO 18 MZT_CS
6 + 5V
7 Write - SDI 15 MZT_DI
8 Read - SDO 3 MZT_DO

looks easy enough to wire up. Tested - doesn't work, just says "Playing ..." and nothing more happens. Let me change pin 3 on Arduino to pin 17 and re-test. MZ_DO connected to pin 17, code changed, compiled and uploaded - no, still doesn't work. Also tested Ultrafast mode, that doesn't work either.

2018-12-06: ok, I created a working set of buttons, and now the file selecting works, and I can select a file, and the display shows "Playing...", so I guess it is time to wire it up to the MZ-721 next.

2018-12-06: mega2560 - tested MZ-SD2CMT on its own (not connected to the MZ-721) with a set of homebuilt analog buttons. Some of the buttons don't work properly (I need to check my wiring), but the file selection works, and it says "playing" when I select a *.mzf file. Good.

2018-12-05: by unscrewing the two screws on the back of the MZ-1T01 data recorder, it can gently be lifted out and the cable disconnected. Perhaps this is connector P-12? Yes, the article MZ-700 data recorder confirms it.

2018-12-05: connected the MZ-721 to power, and to video in on a monitor I have. Power on, and I get the monitor on a nice blue background:

**  MONITOR 1Z-013A  **

waiting for input. Nice that the machine still works.

2018-12-05: I dusted off the MZ-721. There are no connectors on the back to connect a MZ-SD2CMT to, so I'll probably need to remoe the data recorder if I want to try that.

2018-12-04: I bought a 2x16 LCD From ( 90215 NOK 89.90) and connected it to my MZ-SD2CMT on the Mega2560 in 4-bit mode based on the HelloWorld example and LiquidCrystal() reference documentation. I used the pins defined in MZ-SD2CMT:

Arduino LCD
4 d4
5 d5
6 d6
7 d7
8 RS (Register Select)
9 EN (Enable)

The RW pin on the LCD is connected to GND.

It works, now I only need to wire up some buttons. It is a blue display. Notes: a way to adjust the VO pin on the display is required (a 10 kohm pot between 5 V and GND, wiper connected to VO) or else you don't get any characters on the diplay. Also, the backlight is useful (K to GND, A to 220 ohm, then to +5V) else it is very difficult to see stuff on the display. I wonder how much current the backlight draws? With 220 ohm and 5V the current is around 22 mA (probably less, the backlight LED also takes a bit of the voltage). Let me try to change the resistor to 470 ohms. Yes, that works too. The current should now be around 10.6 mA (or less). So I could probably use a pin on the Arduino to turn on or off the backlight too.

2018-11-30: I connected a SD card adapter to a Mega2560, and tried out MZ-SD2CMT from Sharpentiers this evening. First I had trouble getting the SD card detected, but once I checked Arduino's SPI documentation, I found out that MISO and MOSI was switched in MZ-SD2CMT docs. The correct order for a Mega2560 is * 50 MISO * 51 MOSI * 52 SCK * 53 SS after that, the SD card is detected, and I get this on the serial monitor:

         0 2018-11-30 20:17:32 sharpentiers/

I don't have a display or buttons connected to the Mega2560 yet, so I can't test more.

2018-11-29: Unicard mk3b is interesting. Forum thread.

2010-08-26: Loading the basic tape results in


followed by


when it finished. Cool!

Turning over the tape (to "APPLICATIONS"), and doing LOAD from Basic gets me Found "OPENING" LOADING "OPENING" This is a demo program written in Basic. Luckily, you can use SHIFT + BREAK to break out of it. The next program on the tape is MUSIC, which plays "Toy Symphony" by Haydn. Or something resembling music. COLOR PLOTTER is the next program on the tape. Since I don't have a working paper holder right now, I haven't tested it. There are no further programs on this tape.

2010-08-26: I connected the video output to my TV set, connected power and turned it on. This is what was written on screen: MONITOR 1Z-013A * Cool!

2010-08-26: I bought a Sharp MZ-721 for NOK 400.- The machine came with a manual (in Norwegian), a power cable and a RF-cable, and a roll of printer / plotter paper. The paper guide and the right paper holder is missing. The transparent cover for the function key labels is also missing. The Basic / Applications tape (V1.0A) was included, as well as tape 2 of "10 Plays for MZ-700", and a user tape labeled "EE-TIPPS".