I knew there are couple of tips on those old NMOS type EPROMs.
1. The 2716 is made in old NMOS technology. It will consume very high DC current than CMOS chip. The 2716 may need up to 200mA programming current. But CMOS 27C16 chip will only need about 20mA current. 2. Due to a higher current is needed to program a NMOS chip, so the pin need to be very clean. The higher contacting resistance only reduce the DC current. This will fail the programming. 3. There are different Vpp for the different chip. Please confirm your chip's programming voltage(Vpp) is correctly selected. The 2716's Vpp can be either 12.7V, 21V and 25V. Incorrect Vpp selecting also fails the programming. 4. Check the USB current from software menu. The current grade reading should be at least 6 or 7. If not you USB port may not provide enough DC current. You need try use a external DC power supply. Since the TOP2005 has no DC jack. So you may connect it to a DC powered USB hub to get higher DC current. 5. Try to read a 2716 see if the reading OK.
Please note, the chip position diagram is located at the left side of ZIF coscket. On the programmer case.
It seems there is a software bug.Never write the 2716 EPROMs. Tested old version software, before the Re1.28. Those versions still got another small bug, but write OK. Every new opened W/R window only be able to read once. You need close and then open the W/R window to read again.
2716 question
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Posted - 02/24/2005 : 11:39:55
