Buy 5V 4Kx8 DIP ns EPROM. You may also like: A 27C M27CF1. A 27C M27CBF1. M27C64AF1. A 32K (4K x8) UV EPROM. Out of Stock. $ Qty: Buy Now. Add To Wish List. Item #: Facebook 32Kbit (4Kb x 8) NMOS UV EPROM. 24 pin. A EPROM then can hold 2 kilobytes (k) of code. A can hold 4k and so on. Some EPROMS are low-power CMOS ICs. These have a.

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This is why the ICs have a clear window in them; to allow the UV light to penetrate epron erase the data. Typical values are 25v, 21v or Here is one of my efforts regarding the latter.

This article is just a basic primer. Getting to erom with EPROM programming, and having the gear to do it, is worthwhile if you want to maintain a vintage computer collection. There are 8 kilobits in a kilobyte. The Willem requires you to set jumpers and dip switches whereas my TOP allows chip selection from software.

A 32K (4K x8) UV EPROM Chips, Caps, Pots – Misc. at Arcadeshop, LLC

First rule is to know the kind of EPROMS you want or are likely to want to burn and get a programmer that can handle them. The incorrect voltage can kill it. Make sure you know the specs you’re dealing with.

Some EPROMS don’t have a window and are not erasable even though they have the same part number as the erasable version. These are inexpensive devices that can be found on eBay. Beware though, as many modern ones will not handle the smaller capacity ICs like the and ones found in very old microcomputers.


Try 20 minutes first and if that doesn’t fully erase the chip try again with a longer interval until you find a time span that does. There are a number of programmers on the market.

EPROM Technical Data

Otherwise there is great risk of zapping the ROM because voltage is applied to the wrong pin! Furthermore, the article doesn’t cover all of the theory and physics. Typically, my eraser will blank a eprkm in about 20 minutes. There are fundamental differences between the “non-standard” TMS made by Texas Instruments and ‘standard” s made by others.

For example, one manufacturer might use 21vpp for their ICs whereas another may use 25vpp. TOPS software showing a binary loaded into the buffer and ready to go! It seems to work well, although at the time of writing the manual for this Chinese eprkm appears to have been written using an early version of Google Translator!

Not all ROM images are available on the Web and it’s a good idea to extract the code for posterity and possible future eprlm

2732A 32K (4K x8) UV EPROM

It may even check automatically. Usually a status bar shows progress.

A couple of VCF folks helped me refine this article. Figure 4 shows a screen shot of my programmer with a 4k System 80 ROM image loaded. If you know the basics though the software is easy enough to follow. Mask ROMS have embedded code that can’t be changed.


Rather it provides enough practical tips and information for readers to attempt an EPROM replacement of failed compatible parts. For your average vintage microcomputer, EPROMS can be recognised by their clear transparent windows, normally covered by some kind of label.

2732 EPROM

They are cheap and flexible but have a bewildering array of jumpers and switches to set. After epeom prefix is a number such as 16, or 32, 64, etc. One is the READ voltage. The other voltage is the programming voltage Vpp. The ICs hold code, often an auxiliary program such as an application, utility or game which can be loaded immediately on startup.

Fig 1 shows my eraser. This is applied to the Vcc pin and is typically 5 volts. There will be an icon or menu selection for this. However the programming devices mentioned below do handle these other chips. Modern programmers use menu-based interfaces that are easy to use. Often the pin-outs of the mask ROM will be different to the EPROM and some kind of “adapter” needs to be made to switch the pins around or the board circuitry altered.

The code needs to be a binary file. Once complete, most software allows you to verify that the image in the EPROM is now the same as the one in the buffer. It is not the harmless UV found in disco lights.