Voltage Blaster
Blasting through the -5V voltage barrier!
What is the Voltage Blaster?
The Voltage Blaster is an ISA card, that provides -5V to computers that use a PSU (Power Supply Unit) that does not supply -5V. It achieves this by using a voltage regulator and supplies -5V to all ISA slots on that machine.
Old AT and ATX PSUs provide -5V. There are a handful of ISA cards, especially sound cards, which require -5V to function at all, or to function correctly:
Unfortunately old PSUs can be very unreliable and can even blow up, risking damage to rare and expensive retro computer parts. Clean and reliable power is important and therefore I recommend using modern PSUs. However they do not supply -5V anymore. Moreoever there are ATX to AT power adapters, and only some versions have integrated voltage regulator to generate -5V.
This is why in 2016 I had this vision of an ISA card, which you simply plugin into an ISA slot of your retro PC, and it will generate -5V for you. I brought up the idea with a few people, but nothing eventuated until, in 2020, through YouTube comments I talked to a user named Necroware. He solved the puzzle of programming a GAL that is required to enable CMS support with Sound Blaster 2. We continued talking through E-mail and the topic of the Voltage Blaster came up. To my delight, he came back with a prototype right away and I was delighted to see this project finally become reality.
The Voltage Blaster needs to inserted the correct way with the PC BACK marking, pointing to the back (IO ports) of the PC. You can also orient yourself against other ISA cards, the components on the cards should all face the same way.
This project is 100% free, everything you need is made free and accessible. You take the supplied Gerber file and place an order with jlcpcb.com/ webite. The PCB is quite cheap, I ordered 20 PCBs for USD 16. You can choose colours and there is a surcharge to remove the serial number if you wish.
You also need a few components:
The LED light is optional, but if you want it you also need:
I ordered the components from lcsc.com/ website. The part numbers are:
Old AT and ATX PSUs provide -5V. There are a handful of ISA cards, especially sound cards, which require -5V to function at all, or to function correctly:
- Roland LAPC-I
- Sound Blaster 2
- Pro Audio Spectrum 16
Unfortunately old PSUs can be very unreliable and can even blow up, risking damage to rare and expensive retro computer parts. Clean and reliable power is important and therefore I recommend using modern PSUs. However they do not supply -5V anymore. Moreoever there are ATX to AT power adapters, and only some versions have integrated voltage regulator to generate -5V.
This is why in 2016 I had this vision of an ISA card, which you simply plugin into an ISA slot of your retro PC, and it will generate -5V for you. I brought up the idea with a few people, but nothing eventuated until, in 2020, through YouTube comments I talked to a user named Necroware. He solved the puzzle of programming a GAL that is required to enable CMS support with Sound Blaster 2. We continued talking through E-mail and the topic of the Voltage Blaster came up. To my delight, he came back with a prototype right away and I was delighted to see this project finally become reality.
The Voltage Blaster needs to inserted the correct way with the PC BACK marking, pointing to the back (IO ports) of the PC. You can also orient yourself against other ISA cards, the components on the cards should all face the same way.
This project is 100% free, everything you need is made free and accessible. You take the supplied Gerber file and place an order with jlcpcb.com/ webite. The PCB is quite cheap, I ordered 20 PCBs for USD 16. You can choose colours and there is a surcharge to remove the serial number if you wish.
You also need a few components:
- LM7905 Voltage Regulator
- 2x 33uF Capacitors
The LED light is optional, but if you want it you also need:
- 330 Ohm Resistor
- LED
I ordered the components from lcsc.com/ website. The part numbers are:
Part number |
Description |
C427634 |
Fixed -25V -5V 2V @ 1A(typ) TO-220 Dropout Regulators(LDO) RoHS |
C3314 |
33uF ±20% 16V 4x7 1000Hrs @ 105℃ Radial,4x7mm Aluminum Electrolytic Capacitors - Leaded RoHS |
C99697 |
Green-yellow 573~575nm Through Hole 5mm Light Emitting Diodes (LED) RoHS |
C58608 |
330 ±1% 1/4W ±50ppm/°C Axial Metal Film Resistor (TH) RoHS |
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Voltage Blaster.
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