Sunday, December 31, 2023

A Manual Programmer for 82s123 and 82s23 PROM Chips

Introduction The 82s123 and 82s23 are PROM chips that were commonly used in older arcade games, vintage PCs, and equipment from the 1970s and 80s.    Many modern programmers do not support these chips often making vintage electronics projects difficult to complete.   This manual programmer can be used to read and write these chips.     PROM chips are written by blowing tiny fuses inside the chip and can only be written once.   If you mistakenly pulse the wrong bit on, you'll need to start over with a new chip.    When completing this board, it is advisable to practice pulsing some blank locations on an already written "scratch" chip like I do in this video. 

The PCB - The blank PCB is available here.   The rest of the parts you can buy via Digikey, Ebay, and others. 

Power - This board requires +5v, +12v, and G which can be tapped from a PC or arcade power supply.    For PC power supply, you can use a standard hard drive power connector.  

Parts required - The parts for this project can be purchased from Digikey, Ebay.   Electronic hobbyists will likely have some of these parts already available in your parts collection. 

You can download this list in Excel format here.   You can also access a direct link to some of the key parts from Digikey here.


Reference Qty Value Note DigiKey or Ebay Part # Footprint
C1 1 100pF Capacitor_THT:C_Disc_D9.0mm_W2.5mm_P5.00mm
C2 1 33 uF 25v Capacitor_THT:CP_Radial_D8.0mm_P3.50mm
C3, C9 2 100 uF 25v Capacitor_THT:CP_Radial_D8.0mm_P3.50mm
C4 1 22 uF 25v Capacitor_THT:CP_Radial_D8.0mm_P3.50mm
C5 1 0.1 uF Capacitor_THT:C_Disc_D9.0mm_W2.5mm_P5.00mm
C6 1 0.01uF Capacitor_THT:C_Disc_D9.0mm_W2.5mm_P5.00mm
C7 1 220 uF 10v Capacitor_THT:CP_Radial_D8.0mm_P3.50mm
C8 1 330pF Capacitor_THT:C_Disc_D9.0mm_W2.5mm_P5.00mm
C10 1 10 uF 25v Capacitor_THT:CP_Radial_D8.0mm_P3.50mm
D1, D2, D3, D4, D5, D6, D7, D8, D9 9 LED 8 Green, 1 Red LED_THT:LED_D5.0mm
D10, D11 2 1N5821 Diode_THT:D_DO-201AD_P15.24mm_Horizontal
J1 1 DIP 16 ZIF Socket Ebay "dip 16 zif socket" Socket:DIP_Socket-16_W4.3_W5.08_W7.62_W10.16_W10.9_3M_216-3340-00-0602J
J2 1 Conn_01x03_Pin 277-1578-ND TerminalBlock:TerminalBlock_Altech_AK300-3_P5.00mm
L1 1 68 uH Inductor_THT:L_Radial_D10.0mm_P5.00mm_Fastron_07P
L2 1 15 uH Inductor_THT:L_Radial_D10.0mm_P5.00mm_Fastron_07P
Q1 1 VP3203N3 VP3203N3-G-ND Package_TO_SOT_THT:TO-92
R1 1 1.3K .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R2 1 15K .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R3, R9 2 0.5 Ohm .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R4 1 180 .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R5 1 470 .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R6 1 10K .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R7 1 4.7K .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R8, R12 2 1K .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R10 1 13K .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R11 1 91K .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
R13, R14, R15, R16, R17, R18, R19, R20 8 1.5K .25 watt Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal
SW1, SW2, SW3, SW4, SW5 5 SW_SPDT 2449-ANT11SF1CQE-ND PromFootprints:ANT11SF1CQE
SW11, SW12, SW13, SW14, SW15, SW16, SW17, SW18 8 SW_Push_DPDT 141-TL2202OAYA-ND PromFootprints:TL2202OAYA
SW20 1 SW_Push Button_Switch_THT:SW_PUSH_6mm_H5mm
SW21 1 SW_DPDT 2449-ANT21SECQE-ND PromFootprints:ANT21SECQE
U1 1 LM555xN 555 Timer DIP8 Package_DIP:DIP-8_W7.62mm
U2, U3 2 MC34063AP Package_DIP:DIP-8_W7.62mm
U4 1 TC4429 Package_DIP:DIP-8_W7.62mm
U1, U2, U3, U4 4 DIP8 Sockets (Optional)
PC Power Supply Cable 1 Ebay item - 112095154991
Power Supply - 12v and 5v1
PC or Arcade

Assembly - Note orientation of blue push buttons.  Don't accidentally install these backwards! 


Old Version 1.3 Problem and Fix -  Unfortunately the 1.3 version of this board had a design flaw and a small number were shipped this way.   All new v1.4 boards have this problem fixed. On the 1.3 board, the address switches are backwards.  For example, address 20 is backwards as 00101 instead of correctly being 10100.   If you have one, I'm happy to provide a refund and you can keep the 1.3 board or provide a corrected replacement.   If you do want to fix your v1.3 board, you'd need to cut 4 traces and add 4 jumpers.   Sorry for the mistake and message me if you have any questions.

Cut these 4 traces...

Add 4 jumpers...

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