Product Overview
SEEQ DQ27128-20 NMOS UV EPROM - 128Kbit 16Kx8 200ns Ceramic DIP28CW, Date Code 8824, NSN 5962-01-359-1151
Condition
Unused NOS. Stored on pink antistatic foam. Quartz UV-erase window is intact and clear, die visible through the window, pins straight with no oxidation or solder, date code 8824 legible on the package. Data content is unknown - these chips appear unwritten but this has not been verified. Sourced from surplus inventory after a company downsizing. Evaluation: Visual inspection only. Function testing not performed.
Ships same business day from our Idaho warehouse. Packed carefully. Honest parts and straightforward service since 1999.
No hassle resolution if there is an issue. Serving customers since 1999.
Product Overview
SEEQ DQ27128-20 - a 128Kbit UV-erasable EPROM organized as 16K x 8-bit, in a ceramic 28-pin DIP package with quartz window. Access time is 200ns. Operates on a 5V supply. NMOS technology. Date code 8824 places production in week 24 of 1988. Carries NSN 5962-01-359-1151, indicating past qualification for government and military procurement. Erasure is accomplished by exposing the quartz window to ultraviolet light, allowing the chip to be reprogrammed repeatedly using a compatible EPROM programmer.
Key Features
- Memory organization: 128Kbit (16K x 8-bit)
- Access time: 200ns (-20 speed grade)
- Package: Ceramic DIP28CW with quartz UV-erase window
- Technology: NMOS UV EPROM
- Supply voltage: 5V operating
- UV light erasable - allows full reprogramming
- Date code 8824 (week 24, 1988)
- NSN: 5962-01-359-1151
- Pins straight, no oxidation, quartz window intact - confirmed by visual inspection
Applications
- Firmware storage in vintage embedded systems and industrial controllers from the 1980s-1990s
- BIOS chip replacement or duplication in period-correct personal computer motherboards
- Arcade game board ROM replacement and restoration
- Retro computing projects requiring a 27128-compatible EPROM at 200ns
- Development and prototyping on older microprocessor platforms where socket accepts DIP28
- Makers and hobbyists burning custom code for single-board computers or vintage hardware experiments
Frequently Asked Questions
Is data already written to these chips?
Data content is unknown. The chips appear unused and unwritten based on sourcing history and visual condition, but this has not been electronically verified. Read the chip with your programmer before assuming it is blank. If it contains data, a UV eraser will clear it.
What programmer and eraser do I need?
You need an EPROM programmer that supports the 27128 family and can supply the required programming voltage for this chip. You also need a UV EPROM eraser to clear existing data before reprogramming. Verify your programmer's device list for DQ27128-20 or 27128 compatibility before ordering.
Will this work as a drop-in replacement for other 27128 EPROMs?
The DQ27128-20 is pin-compatible with other 27128-family EPROMs in a DIP28 socket. Confirm the access time requirement of your target system - the 200ns speed grade must meet or beat what your application needs. Programming voltage requirements can vary between 27128 variants; verify your programmer supports this chip's specifications.
Is the ceramic package important - can I use a plastic-windowed version instead?
The ceramic DIP28CW package is more durable and is the format specified under the NSN for this part. For most development and restoration applications, ceramic and plastic windowed EPROMs of the same part number are functionally equivalent. If your application specifies ceramic (military or high-reliability use), this is the correct package.
Does the chip come with a window cover sticker?
Not included. A UV-opaque label over the quartz window is recommended for any chip in active use - prolonged exposure to ambient light or fluorescent lighting can cause slow data loss over time. These are inexpensive and widely available from electronics suppliers.
A ceramic-window EPROM from 1988 is a chip that has outlasted the machines it was born for - and is now exactly what someone needs to bring one of those machines back to life. Burn it, socket it, power it up. The story picks up wherever you left off.
