Vintage Logic ICs & Memory Chips: 7404, 74LS10, CD4001, 4116 DRAM & 27C256 EPROM Cross-Reference Guide
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Vintage logic ICs and memory chips — including 7404 hex inverters, 74LS10 NAND gates, CD4001 NOR gates, 4116 DRAM, and 27C256 EPROM — are in stock as new old stock (NOS) at American Industrial Parts Group, and new listings are added daily. This guide is part of our obsolete electronic components series; start with our obsolete electronic components overview, then browse Vintage Logic ICs and Vintage Memory ICs.
Vintage Logic ICs and Memory Chips We Stock
| Part family | Type | Key specification | Collection |
|---|---|---|---|
| 7404 (SN7404, DM7404) | TTL hex inverter | Six inverters per chip, 14-pin DIP | Vintage Logic ICs |
| 74LS10 | Low-power Schottky triple 3-input NAND gate | 14-pin DIP, 4.75 V to 5.25 V supply | Vintage Logic ICs |
| 7420 (SN7420) | TTL dual 4-input NAND gate | 14-pin DIP; Texas Instruments lists the SN7420 as obsolete | Vintage Logic ICs |
| CD4001 | CMOS quad 2-input NOR gate | 14-pin; the CD4001B is rated 3 V to 18 V | Vintage Logic ICs |
| 4116 DRAM (e.g., Mostek MK4116) | 16K x 1 dynamic RAM | 16-pin DIP; +12 V, +5 V and -5 V supplies; 128 refresh cycles per 2 ms | Vintage Memory ICs |
| 256K x 1 DRAM (e.g., M5M4256P) | 262,144 x 1 dynamic RAM | 16-pin DIP; single +5 V supply; 256 refresh cycles per 4 ms (family specification) | Vintage Memory ICs |
| TMS27C256 | 32K x 8 (262,144-bit) CMOS UV-erasable EPROM | 28-pin ceramic windowed package, 5 V supply; the "-10" speed grade is 100 ns; listed as discontinued | Vintage Memory ICs |
How to Identify 74 Series, CD4000, DRAM, and EPROM Part Numbers
- 74, 74LS, and 74S families: the Texas Instruments hex inverter datasheet covers the SN7404, SN74LS04, and SN74S04 together. They share the same function and 14-pin layout but are different logic families with different speed and drive characteristics, so check the datasheet before substituting one for another.
- TTL vs. CMOS: 74LS parts run from a 4.75 V to 5.25 V supply, while the CD4001B CMOS gate is rated 3 V to 18 V.
- CD4001 suffixes: confirm the ratings for the exact suffix on your part (such as A or B series) on its datasheet.
- DRAM sizes: a 4116 is 16K x 1, a 4164 is 64K x 1, and a 41256-type part is 256K x 1. They are different devices, not speed grades of one part.
- EPROM markings: 27C256 means a 256-Kbit CMOS EPROM organized as 32K x 8. Ultraviolet light through the window erases the contents.
Common Vintage Logic and Memory Problems
- Need to replace DRAM on a vintage computer or arcade board: identify the exact type first. The 4116 was used in systems such as the Apple II and Commodore PET and in arcade games such as Defender and Missile Command, and eight chips are typically used in parallel to store bytes.
- Need a replacement EPROM: match density (256K is 32K x 8), the 28-pin package, and the access time your board requires.
- Logic gate failed on a vintage board: match both the function and the family, for example 7404 vs. 74LS04.
- Original part is obsolete: Texas Instruments lists the SN7420 as obsolete and the TMS27C256 as discontinued. NOS stock lets you buy the original part.
- Need matched parts for a full repair: many items are available in lots of 10.
Compatibility Notes Before You Order
- Do not mix DRAM types: the Mostek MK4116 uses +12 V, +5 V and -5 V supplies, while 64K x 1 and 256K x 1 DRAMs use a single +5 V supply and need 256 refresh cycles per 4 ms. Confirm the type your board was designed for.
- Package style: some DRAM listings are ceramic DIP and others plastic DIP. The package is stated in each listing title.
- EPROM contents: an erased or blank EPROM must be programmed with your board's code before use unless the listing states otherwise.
- Condition: each listing states whether the part is NOS, new, or used. Sockets are not included unless listed.
Vintage Logic IC and Memory Chip FAQ
What is the difference between a 7404 and a 74LS04?
Both are hex inverters in a 14-pin package, but they belong to different logic families (standard TTL and low-power Schottky) with different speed and drive characteristics. Check the datasheet before substituting.
Can I replace a 4116 DRAM with a 4164?
No. The 4116 is 16K x 1 and the Mostek version uses +12 V, +5 V and -5 V supplies, while the 4164 is 64K x 1 and runs on a single +5 V supply.
What does 27C256 mean?
It is a 256-Kbit CMOS EPROM organized as 32K x 8. The TMS27C256 is a UV-erasable version in a 28-pin windowed ceramic package.
How often is new inventory added?
New vintage logic ICs and memory chips are added to the site daily. Check the collections below for the latest listings.
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