OLD SEMICONDUCTORS
As part of the process of investigating and repairing old calculators and computers, I've ended up accumulating some interesting "vintage" parts.

Note: The LED displays that previously were on this page have been moved to a separate page here.

SN94281
The SN94281 Complex Sound Generator is a 16-pin sound effects integrated circuit.

The datasheet (this one from Radio Shack) has eight panels.

SN 76477 N COMPLEX SOUND GENERATOR
This is a Texas Instruments SN76477N complex sound generator sold by Radio Shack as catalog number 276-1765.

I had two of these, still in the package - they were traded for some other interesting old items.

Click here for a 4-page article on this chip from the October 1978 issue of Popular Electronics. (Article is in Adobe PDF.)

VOICE SYNTHESIZER IC
Voice Synthesizer IC
SP0256-AL2
Allophone Speech Set

(Radio Shack 276-1784)

C1702A
Eraseable Programmable Read-Only Memory (EPROM) on ceramic base.

I have four of these chips.

MM1702AQ
Eraseable Programmable Read-Only Memory (EPROM) on ceramic base.

I have four of these chips.

CLOCK CHIPS
MK5017

The Mostek 5017 is used in the Heathkit GC-1005 (MK5017PAA), GC-1092A (MK5017AA) and GC-1092D (MK5017BA) clocks, as well as other timekeeping products.

You can see the datasheet for this chip here.

You can see a clock project using this chip by clicking here.

This particular one is stamped Archer (Radio Shack's house brand), RS1755 with a date code of 7441 (1974). This is Radio Shack part number 276-1755. Apparently the MK6207N is a pin-compatible equivalent.

If you have any of these chips you'd like to part with, please send me an e-mail!

 
MM5309
 
MM5311
 
MM5313

This chip is used in the MITS DC-6 clock, which typically came as a kit.

 
MM5316

This is a four-digit non-multiplexed clock.

I have a whole bunch of these.

 
MM5375AB

12 Hour 60 Hz 6-digit clock

Part Number Pins Package Hold Strobe 1 PPS 7 Seg BCD Digits
MM5311D 28 Ceramic x x x x 4/6
MM5311N 28 Molded x x x x 4/6
MM5312D 24 Ceramic x x x 4
MM5312N 24 Molded x x x 4
MM5313D 28 Ceramic x x x x 4/6
MM5313N 28 Molded x x x x 4/6
MM5314D 24 Ceramic x x x 4/6
MM5314N 24 Molded x x x 4/6

Click here for a datasheet that describes the MM5309, MM5311, MM5312, MM5313, MM5314 and MM5315 clock chips.

Click here for the MM5316 datasheet.

Click here for a single-digit clock design using the MM5314.

MM5837 DIGITAL NOISE GENERATOR
This is a digital noise generator, Radio Shack part number 276-1768.

A kind reader sent some application data which you can read here.

MM5736
I have a bag of 10 MM5736N calculator chips.

RANDOM ACCESS MEMORY
MCM2114P20 (4), uPD2114LC (1): Motorola 4K static RAM (1Kx4)
8040016 (80): 16K dynamic RAM (4116) 200nS (Radio Shack catalog 276-2503)

"Universal Memory Board": Radio Shack catalog 276-184

MISCELLANEOUS
2518
2527V
P2102
SD1101

Miscellaneous Radio Shack Parts
Part NumberDescriptionQuantity
MM5871
276-1785 		Rhythm Generator IC 3
276-1646 Hall Effect Switches (3) 2
74150
276-1829 		16-Line to 1-Line Multiplexer 1
74154
276-1834 		4-Line to 16-Line Decoder/Demultiplexer 1
74192
276-1831 		Synchronous Decade Up/Down Counter 2

MYSTERY CHIP
Mystery chip.

I have one of these chips.

A viewer has identified the logo as General Instruments.

ANOTHER MYSTERY CHIP
Unmarked, what looks to be an EPROM.

I have seven of these chips.

MYSTERY CHIP
This chip is stamped MM5202AQ but I haven't been able to find out more information about it.

Update: I've been informed that this is the same as a 1702 EPROM.

Send comments to Dan Veeneman

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Last updated June 18, 2005.