as above?

 

27 series usually need UV light.

29 series are electrically erasable.

 

is a common "blacklight" sufficient?

How long does it need to be in contact with the light?

 

no but a germicidal lamp from the pet store will be.

 

The short answer for me is 5 to 7 minutes.

My Ango eraser uses a 4W Germicidal tube. The instructions say the time required to complete an erase cycle will depend on two factors: the intensity of the UV source; the erase energy required as specified by the EPROM manufacturer in Watt-Second per sq.cm. Erase time = (erase energy)/(intensity of UV source).

For my eraser, I find that for one chip, 5 to 7 minutes is enough to get all FF's, but the instructions says the erase time varies as follows (with the chip layout and energy required):

John

 

Thanks,

It is a 27C128 chip. And it was completely erased in 45 minutes.
I think with my UV eraser light Eproms will erase in about 20 minutes which is confirmed in the table above.

Thank you to all who responded.

 

Doc, is this a "virgin" eprom or has she been around the block a couple of times?

I always started with 10 minutes and then slowly increased the time as used it.

Before I finally threw all my eproms in the garbage and went Flash Prom (hint), I found that after a couple times erasing at one time, that I would have to slowly start increasing the time if I wanted the eprom to erase properly for a good "reburn".

Early on when I first started to burn eproms, I found that after about 4-6 times of burning (let's say I was using 10 minutes to erase each eprom), that if I didn't increase the erasing time (I used 1 minute increments) that the eprom would appear to be erased properly, appear to burn properly, started the car and ran.

BUT - I would get a weird error code after about 15 - 30 minutes of running the car. Initially I thought it was something weird with either the (then) new version of TunerCat, Xtronics burning software or the eprom.

I had a spare Memcal, with the IDENTICAL BIN on it and it ran GREAT with no error codes.

I then took that eprom and increased the erasing time and VOILA, now the eprom was working great. That is when I started to control and record the erasing time I used for each eprom - trying to increase the erasing time at the slowest rate to get the maximum number of uses out of the eprom until it eventually was taking a LONG time to erase properly and finally wouldn't.

Lastly, the amount of "initial time" also is affected by how close the window in the eprom is to the UV Light. I used to erase the eprom directly on the Memcal, but I found that the slight difference in distance (compared to an eprom not installed in a Memcal) was enough to affect the erasing times.

 

do you need to change anything to switch over to flash PROMS? or is there different hardware you need...

i would love to switch over, do i just need to buy some flash chips?

 

King, you just swap the Flash Prom (Atmel AT29C256) in place of the stock 27C256 (or 27C128) - and set the your "burner/programmer" to the AT29C256. That's it.

You may wish to consider Craig Moate's adapter with a Flash Prom or two. It REALLY saves the socket on your ECM over the long hall. Better to bend a pin or two on a Flash Prom which is only a few bucks rather than damage your ECM from continous removal/reinstallation of the Memcal.