Which blank proms to buy?

[ILIKEMYTBI]

Hey all, I have a question for you. Which blank Proms do I need to purchase? I am trying to figure out which style would have came in my 6299 ECU and also in a 7747 ECU. Any help would be appreciated. From what I gather the '7747 is going to use a 2732 prom and the '6299 is going to use a...? I am not sure.

Jacob B.

[Six_Shooter]

Both ECMs originally used 24 pin PROMs, 2732s, there's also mention that they had 27128, 27256 and 27512s installed, but the 2732 is most common.

Most user programmed EEPROMs will be the SST 27SF512 or equivalent. This is a 28 pin EEPROM, and requires an adapter and a modified ECM (replace the PROM socket with a 24 pin DIP socket) in order to use.

24 pin PROMs are usually older stock and are UV erasable, which also seem to have issues with being programmed multiple times, some will program once, some twice, some multiple times. It's hit and miss.

[dave w]

The 4K chip used for most TBI computers is the 2732, which has variants like the 2732a. The challenge with 4K TBI computers is the NOT the chip, but the CHIP HOLDER!

To my knowledge, the salvage yard is the only source for chip holders. Usually salvage yards will only sell computers, not just the chip / chip holder.

The 2732 requires a Ultra Violet Light to erase the chip, before the 2732 can be reprogrammed.

Newer Chips like the Electronically Erasable Programmable Read Only Memory (EEPROM) are affordably supported by companies like Moates.net using the Burn2 http://www.moates.net/burn2-chip-programmer-p-197.html

For some TBI projects upgrading to the 27SF512 EEPROM is a good option: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?172-7747-Flash-Chip-Conversion-(27SF512)

I have several TBI computers without Chip Holders, which is why I posted information on how to convert to the 27SF512 chip.

dave w