T48 programming for vintage EPROMs

[datwyver]

My new XGecu T48 programmer arrived yesterday and I had good success making copies of two different old TMS27C512 EPROMs from my system.

However, I need to also make copies of six old Cypress CY7C291-50WC CMOS 2K EPROMs. Unfortunately this device is not in the T48 supported list. I tried selecting AMD 27C16 and M2716 as they are supposed to be pin compatible. I adjusted the VPP to 12.5 volts and the delay to 100ns to match the CY7C291 specifications, but in both cases the T48 returned a buffer of all FFs when reading. The same thing happened with two other devices from my system. I know that my devices are not blank as I just removed them from a working system.

Any advice on configuring the T48 correctly for my CY7C291 devices would be appreciated.

Dave

 

[Bruce Tomlin]

Did you look at the data sheet? It has three chip select inputs. Try reading it as a 2732.

 

[gslick]

I don't see how trying to read a CY7C291 as a 2732 would help.

The CY7C291 pins 18 - CS3, 19 - CS2, and 21 - A10 don't match any other common EPROM pinouts that I have found.

In particular, pin 18 - CS3 is the opposite polarity of every other common EPROM pinout.

 

[Bruce Tomlin]

Then bend the problem pin up out of the socket and connect it with a resistor to either +5 or GND.

 

[datwyver]

No Luck as 2732 or as CY27C128. Still all FFs.