Phil_G
Experienced Member
...which equates to at least 27000 erasures! no doubt their output will decline slightly over time, but the decades-old tubes mentioned above still do their job perfectly 
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You're absolutely right....which equates to at least 27000 erasures! no doubt their output will decline slightly over time, but the decades-old tubes mentioned above still do their job perfectly![]()
Yes, the purpose of the timer is obvious. However, it is a simple mechanical timer that is not designed to measure any defined length of time, and cannot be reset but instead has to be left to run until it "winds down". Therefore, I just use it along with the power switch to turn the eraser on and then go "by the clock" to know when to turn it off. Generally, that box takes 10-15 minutes to erase most EPROMs.@hmb The timer is used to turn the lamp on for a fixed amount of time. It's a simple and inexpensive safety measure, as long as it works properly.
Interesting. How long do you typically run it for an erase?I use one meant for sterilizing a phone now...
This one is very similar to one I have.
View attachment 1322975
What is the correct distance between the EPROM window and the lamp surface?20 minutes total, without stopping the timer I check at 12 minutes or so that the eprom is now blank then give it the remaining time up to 20 minutes.
Some 'active' erasers read the contents continuously whilst erasing, they too gave it a few more minutes after its blank to be sure.
What is the correct distance between the EPROM window and the lamp surface?
I was wondering because UV-C emission undergoes inverse quadratic dispersion in relation to distance, which will affect the exposure time: if you double the distance from the lamp, the intensity becomes 1/4.The RS eraser tubes are about an inch or so above the chip drawer.
Maybe it's because I've already cooked too many EPROMs...You're way, way overthinking this. Some people use sunshine![]()
I’ve got one like this: https://ebay.us/m/KywY6R
It’s incredibly cheap feeling, and the timer seems very inaccurate.
It seems to work fine, but for fear of burning down my house I’ll only use it if I can keep an eye on it.
I don't understand.20 minutes total, without stopping the timer I check at 12 minutes or so that the eprom is now blank then give it the remaining time up to 20 minutes.
Some 'active' erasers read the contents continuously whilst erasing, they too gave it a few more minutes after its blank to be sure.
This is my experience with the TMS2532A EPROM:EPROMs don't store light. The UV erases the cells back to a known state to be written again.
Since the memory cells don't uniformly erase at the same time, you have to keep the UV on the entire chip for an extended period of time so they all erase. You can do read checks every few minutes and watch the data disappear.
But unless you're having an issue, just run the chip for 20 minutes to avoid excessive UV exposure to yourself.
No, after 20 minutes it will definitely be erased. Very very seldom does a stubborn eprom need longer.I don't understand.
If your EPROM usually erases in 20 minutes but isn't completely erased after 12 minutes, do you persist with 12-minute sessions?