Erasing and using UV PROMs

uv-proms

Hi all!

Just got some new chips in the mail today! :sm16:
As a bonus the guy i bought them from gave me a pipe of MBM27C64 PROMs!
(realy nice guy!)

The questions are:

1. Can i use my expusurebox for PCBs (UV) to erase PROMs?
2. What kind of programmer do i need?
3. Is the pin out standard for all x27x64x chips?

Best regards / Hampus

PROMS cannot be ereased, EPROMs can. The MBM27C64 is an EPROM.
1. I have used the same UV lamp (germicidal) for exposing photoresist and erasing EPROMs with no problems.
2. Some programmers:
**broken link removed**
**broken link removed**
3. The pinnouts are compatible even between EPROMS of diferent capacities. See the description on the 2nd link above.
Regards

Hello Cosmox,

A normal PCB UV unit won't usually do it, some people report it does but takes a *long* time.

UV EPROM's need short wavelength UV, PCB units use medium/long UV.

As Albert22 said, you can use a germicidal lamp - these are short wavelength. Be careful though, the light from these *does* cause eye and skin damage - it can cause skin cancer. That's why UV erasers have an interlocking lid.

You can buy them from aquarium or pond shops - they are small fluorescent tubes. The small ones only cost about £5 (UK) and the easiest way to power one is to buy a cheap, fluorescent torch with the same length tube and swap the tubes over. Add some wires to remote switch it, but it in a lightproof box a few cm's away from the EPROM window and expose for about 15-20 minutes.

Of course, you can also get them from electonics suppliers, but at a higher price. You could also power it from a simple 6" fluorescent driver circuit - there are many on the web.

FoxyRick.

Do yourself a favor and spend the $40 for a
real EPROM eraser. The germicidal lamp itself
will cost half of that - then you will need the
proper ballast, housing, switches, safety interlock,
etc. When a $40 commercial product is available,
doing it yourself is just not worth it - especially
with something that could blind you (or your kids,
dog, etc). Walling makes a nice little unit, the Datarase.
It'll last your lifetime, if not longer. Or if that is too
much, check Ebay. Since the world is going flash, there
are always good deals to be had on used UV erasers. HTH

Nick

Hi Nick,
Where can get the $40 EPROM eraser? Can u give me advise? Thank you!

Stacy

This E-PROM eraser is easy to build and you will not spend a lot of money on it:
https://www.romanblack.com/tube4w.htm
Regards,
IanP