Z80 CPU NMOS/CMOS Tester
New Production, Yellow solder mask PCB
The board can be used to test Z80 processors and can determine the type of processor (CMOS or NMOS). This is very important today, when incorrect suppliers from China offer rebranded, second hand processors.
The device comes with a quartz generator at 16MHz and with the help of a divider and jumpers the operating frequency of the processor can be selected - 16MHz, 8MHz, 4MHz, 2MHz or 1MHz. If needed, the user can replace the existing or add a second 20MHz generator and get 20MHz, 10MHz, 5MHz, 2.5MHz or 1.25MHz CPU clock speeds.
Unlike a simple NOP tester, this one works by loading a simple program from the EPROM/EEPROM. It first checks the variant by using undocumented instructions like OUT (C),0 , flashes the LED array one to three times to indicate the type, and then does a LED chaser display up and down the various data bus lines. Takes up to two 1/2 can oscillators and with the frequency dividers can test at the following frequencies.
Usage
Supply 5V center positive to the 5.5mm x 2.1mm DC power jack. On power up, the Z80 should automatically reset, if not, push the reset button. The LED array will flash once for NMOS variants, twice for CMOS, or three times for a U880. After that, the LED's will go "knight rider", and then reset in a continous loop. Use the two jumpers to select the appropiate osciallator and frequency divider you want to test at.
| Divider | 20 MHz Oscillator | 16 MHz Oscillator |
|---|
| Full | 20 MHz | 16 MHz |
| 1/2 | 10 MHz | 8 MHz |
| 1/4 | 5 MHz | 4 MHz |
| 1/8 | 2.5 MHz | 2 MHz |
| 1/16 | 1.25 MHz | 1 MHz |
JP1 (Current Test) feeds 5V to the Z80. Remove the jumper and attached a multimeter in current mode if you would like to test current draw of your Z80, another way to tell NMOS and CMOS variants apart. NMOS is around 200mA, CMOS is between 10 to 100mA depending on clock frequency.
Notes:
While this is a good test to determine if you have a dead CPU it will not test all address lines and functions of the Z80.
Use only a stabilized 5V power supply with a center positive DC barrel jack. Otherwise, you will damage the device and the tested processor! A USB to DC center positive jack adapter can also be used.
Make sure the Z80 is inserted correctly. Pin1 to lever. (See last photo) The tester does not come with a Z80 CPU as shown in the picture. This is for illustration only.
SHIPPING & PAYMENT INFORMATION:
• Shipments are sent by standard air mail and tracking number, usually USPS for USA and Deutsche Post for other destinations!
• Delivery time - 6-21 business days (varies depending on the country of destination).
• The buyer is responsible for all shipping cost and taxes.
•
All returns (where is applicable ) must be made within 30 days from the
payment date. The returned product(s) must be in the same condition as
it was sent to you.