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ISA OPL2 Card is a sound card based on Yamaha OPL2 chip, officially known as YM3812. This card is compatible with the AdLib Music Synthesizer Card that was very popular in late 80's - early 90's.



The ISA OPL2 is relatively easy to build, and most components are widely available. YM3012 (OPL2) and YM3014B (DAC-SS) can be more tricky to get, but they are available on eBay, and from some electronic component suppliers specializing on obsolete components. Please refer to the Bill of Material below for the complete list of components. Also see attached schematic and board layout files on the bottom of this page.

Assembling the ISA OPL2 card

Follow good soldering practices: Clear the board with alcohol before soldering; Use solder with flux; Keep soldering iron tip clean; Apply the minimal amount of solder necessary to fill the hole around the lead.

Start with soldering low profile components - diode and resistors. Using needle nose pliers carefully bend resistors' and diode's leads at 90 degrees angle, so that the distance between bended leads is about 7.5mm / 0.3". Be especially careful with the diode, as it is easy to break it by bending leads too close to the package - hold pliers closer to the package, and bend the lead next to the pliers. Pay attention to the diode polarity. The diode has a black stripe that goes around the package, this stripe indicates the cathode, and it should match the orientation of the stripe on the board's silkscreen. The resistors have different resistance marked by the color codes - Google it if you are not familiar with these codes.

Continue with the capacitors (except of C18). If you are using polarized (electrolytic or tantalum) capacitors, pay attention to their polarity. Electrolytic capacitors usually have a stripe with minus (-) signs that indicate the negative lead, the board has positive pin marked with (+). Tantalum capacitors usually have a small plus (+) sign near the positive lead. Capacitance is usually marked explicitly on electrolytic capacitors (e.g. 10 uF), while ceramic and tantalum capacitors use exponential notation in format NNE. To calculate the capacitance use NN * 10 ^ E formula. For example 104 means 10 * 10 ^ 4 = 100,000 pF or 0.1 uF.

Solder the Q1 transistor, make sure it is oriented correctly (package matches the drawing on the silk screen).

Next solder IC sockets (or ICs directly if you're brave). Pay attention to the sockets/ICs orientation. The first lead is marked on the silkscreen with a notch. Sockets usually have similar notch, ICs might have either notch or dot near 1 pin or frequently both of them. I usually solder two opposite pins first while applying slight pressure to the socket/IC so it sits firmly on the board. Then I check that socket/IC is indeed oriented correctly (in case it is not oriented correctly, it is not very difficult to desolder it at this stage), and solder the rest of pins.

Finally solder taller components - C18 capacitor, headphone socket J1, and the potentiometer RV1.

Carefully inspect all solder joins. Resolder any missing or questionable joins.

It is recommended to clean the flux from the finished board with alcohol (I use a toothpick to remove the excessive flux, and the 91% rubbing/isopropyl alcohol, and an old toothbrush to clean the board). Let the alcohol to dry before continuing.

If using sockets - insert ICs to sockets at this stage. Pay attention to the ICs orientation. It is usually necessary to bend IC pins a bit, so they will fit in the socket. Do that by gently pressing ICs against a firm surface (table, ruler). If you overbend them, use a metal ruler to bend them back by placing the ruler between pins and the package, pressing the ruler against a firm surface and applying a slight pressure to the package.

Drilling the mounting bracket

First measure and mark holes' positions with a permanent marker or a metal scriber. Next use a center punch (or a large screw with pointy tip) and a small hammer to mark holes' centers. Place the bracket on a piece of wood, and secure it with a clamp. Start drilling with a small drill diameter gradually increasing the drill diameter. Use low speed then drilling larger diameters, do not apply to much pressure, or the bracket will bend. The final diameter should be about 7 mm - 8 mm (5/16") for both holes.

Bill of Materials

 Component Type
 Reference  Description
 Quantity  Possible sources and notes
   ISA OPL2 PCB  1  Order from Sergey or make your own
 Integrated Circuit  U1  74LS245  1
 Mouser 595-SN74LS245N
 Integrated Circuit  U2, U3
 74LS138  2
 Mouser 595-SN74LS138N
 Integrated Circuit  U4
 74LS74  1
 Mouser 595-SN74LS74AN
 Integrated Circuit  U5
 74LS04  1
 Mouser 595-SN74LS04N
 Integrated Circuit  U6
 YM3812  1
 eBay, Utsource
 Integrated Circuit  U7
 YM3014B  1
 eBay, Utsource
 Integrated Circuit  U8
 RC4136  1
 Mouser 595-RC4136N
 Integrated Circuit  U9
 LM386-3  1
 Mouser 926-LM386N-3/NOPB
 Transistor  Q1
 2N3904  1
 Mouser 512-2N3904TA
 Diode  D1
 1N4148  1
 Mouser 512-1N4148
 Capacitor  C1 - C11
 0.1 uF ceramic, 5.08 mm pitch  11
 Mouser 810-FK28X7R1H104K
 Capacitor  C12 - C17
 10 uF, 16V, multilayer ceramic or tantalum, 5.08 mm pitch  6  Mouser 810-FK24X5R1C106K
 Capacitor  C18  220 uF, 16V, electrolytic, axial, 16 mm x 8 mm  1  Mouser 647-TVX1C221MAD
 Capacitor  C19  4.7 uF, 16V, multilayer ceramic or tantalum, 5.08 mm pitch  1  Mouser 810-FK24X7R1C475K
 Capacitor  C20  47nF, ceramic, 5.08 mm pitch  1  Mouser 810-FK24X7R2A473K
 C21 - C24
 4.7 nF, ceramic, 5.08 mm pitch  4
 Mouser 810-FK28X7R1H472K
 1 nF, ceramic, 5.08 mm pitch  1  Mouser 810-FK28C0G2A102J
 270 pF, ceramic, 5.08  mm pitch  1
 Mouser 810-FK28C0G2A271J
 Resistor  R1
 12 k, 1/4 w  1  Mouser 291-12K-RC
 Resistor  R2 - R5
 10 k, 1/4 w  4  Mouser 291-10K-RC
 Resistor  R6
 8.2 k, 1/4 w
 1  Mouser 291-8.2K-RC
 Resistor  R7 - R13  2.2 k, 1/4 w  7  Mouser 291-2.2K-RC
 Resistor  R14  1.5 k, 1/4 w
 1  Mouser 291-1.5K-RC
 Resistor  R15 - R17
 10 ohm, 1/4 w  3  Mouser 291-10-RC
 10 k, audio, Bourns 91A1A-B24-D15L
 Mouser 652-91A1A-B24-D15L
 Audio Connector 3.5mm, Stereo
 Mouser STX-3120-3B-577C
 IC Socket
 U7, U9
 8 pin 300 mil DIP socket  2
 Mouser 517-4808-3000-CP
 IC Socket
 U4, U5, U8
 14 pin 300 mil DIP socket  3
 Mouser 517-4814-3000-CP
 IC Socket
 U2, U3
 16 pin 300 mil DIP socket  2
 Mouser 517-4816-3000-CP
 IC Socket
 20 pin 300 mil DIP socket  1
 Mouser 517-4820-3000-CP
 IC Socket
 24 pin 600 mil DIP socket
 Mouser 517-4824-6000-CP
 Bracket    ISA Bracket, Keystone 9202  1
 Mouser 534-9202
 Screw    Screw, 4-40 thread, 1/4" length
 Mouser 534-9900

Replacement Notes

  • 74LS logic ICs can be replaced other TTL or TTL-compatible CMOS ICs. For example these from 74ALS, 74F, 74AHCT, 74HCT, 74ACT series
  • 1/8 W resistors can be used. It is not recommended to use resistors above 1/4 W, as they have larger packages, and won't easily fit in the board.

Sergey Kiselev,
Sep 27, 2012, 9:27 AM
Sergey Kiselev,
Jan 14, 2021, 9:21 AM
Sergey Kiselev,
Dec 4, 2012, 8:36 AM
Sergey Kiselev,
Sep 27, 2012, 9:27 AM
Sergey Kiselev,
Jan 14, 2021, 9:21 AM
Sergey Kiselev,
Sep 25, 2012, 10:49 PM
Sergey Kiselev,
Sep 25, 2012, 10:49 PM
Sergey Kiselev,
Sep 27, 2012, 9:27 AM
Sergey Kiselev,
Jan 14, 2021, 9:25 AM
Sergey Kiselev,
Sep 27, 2012, 9:27 AM
Sergey Kiselev,
Jan 14, 2021, 9:21 AM
Sergey Kiselev,
Sep 25, 2012, 10:36 PM
Sergey Kiselev,
Sep 25, 2012, 10:36 PM