Commodore C128DCR internal PSU

Commodore 128 DCR internal PSU by Electroware: new internals for your desktop Commodore 128DCR. Efficient & reliable 120W PSU to power & preserve! Replacing the original power supply units and offering peace of mind as it's always equipped with Electroware's OVP circuits, output voltage fine tuning, advanced ripple filtering. Easy to replace fuses and two auxiliary universal power outputs  to power your eventual C128 enhancements or external FDDs!

Stay original! Buy only the genuine Electroware's gear and beware the fancy overrated clones flooding eBay & WWW!

Commodore 128 DCR internal PSU : THE NEW POWER TO GET READY AGAIN.

Based on our experiences with successful and well-known Commodore 128 external PSU model I decided to make it 10A@5VDC, 5A@12VDC and 1.5A@9VAC giving around 120W of total power. You don't need to use it all but working with 50% of nominal load will result in few advantages: lower noise, reduced heat emission and longer component life. PSU is by default equipped with our famous over voltage protections: independent OVP circuit for both 5V and 12V rails. 5VDC and 12VDC voltage tuning in safe range (to feed your accelerated machines stuffed with add-ons), easy to replace fuses and two universal connectors (5VDC & 12 VDC) to supply external devices like FDD, Ultimate II+, cooling fans or any other internal/external devices (even an external 1541-II or 1581 FDD drive with some special-made cable).

 

Based on our experiences with successful and well-known Commodore 128 external PSU model I decided to make it 10A@5VDC, 5A@12VDC and 1.5A@9VAC giving around 120W of total power. You don't need to use it all but working with 50% of nominal load will result in few advantages: lower noise, reduced heat emission and longer component life. PSU is by default equipped with our famous over voltage protections: independent OVP circuit for both 5V and 12V rails. 5VDC and 12VDC voltage tuning in safe range (to feed your accelerated machines stuffed with add-ons), easy to replace fuses and two universal connectors (5VDC & 12 VDC) to supply external devices like FDD, Ultimate II+, cooling fans or any other internal/external devices (even an external 1541-II or 1581 FDD drive with some special-made cable).

 

My both C128DCR units.

C128 DCR computers were equipped with two models of internal PSU (see photos as I've extracted both of them from my hardware here). Switching mode Mitsumi 68-4224A PSU seems to be quite reliable and quality built but it's not longer complying with nowadays standards. The "8708" PSU from Commodore is rather a economic construction, carrying heavy transformer unit and generates a lot of heat while converting the AC-to-DC voltages. Big transformer is giving an annoying magnetic humming once powered on, causing entire desk to vibrate :)

Both of original PSUs can be re-capped to last longer, repaired (especially the input AC cables soldering for 8708 unit needs a review) or upgraded, but even then you can't be sure as 35 years old electronics may fail anytime and the damages done to the C128 main board may be very painful (not only the RAM chips burned) as it's powering the 1571 FDD as well...

If your Commodore 128 DCR original PSU not longer working or you are not sure about it's condition - it's time to get a superior quality replacement. Especially if your C128 is using many modern enchantments like ULTIMATE-II+ etc you need to remember that all of these gadgets are stressing the PSU. The original Commodore PSU become even more dangerous when working overloaded.

To install the replacement PSU you need to keep the original PSU mounting plate, screws, power switch and AC connector as shown on the pictures. Replacement PSU is exchanging the electronic board and the output cables only. As the PSU is providing the real 9VAC output with use of real analog transformer unit (just like the original) please mind to choose the correct input voltage version: 230VAC (Europe) or 115VAC (USA, Canada, Japan).

This new replacement PSU is compatible with Commodore 128D-CR (metal case or so-called "cost reduced") but it's not compatible with less popular 128D (first release in plastic case including handle and keyboard bay, which for some reasons was not originally offered in USA). To save costs we are utilizing the original mounting plates, runners, covering shields, AC connector and power switch (these parts needs to be extracted from your C128, fortunately it's easy). Notice that some basic electric knowledge and tools are needed to replace the PSU the safe way but most of all: please notice you are working with high AC voltage - so to avoid electric shock, always operate with main AC cable unplugged and do not connect or turn it on until fully mounted, double-checked and covered with all shields.

Internal voltage fine tuning potentiometers are located on the safe low voltage side of the PSU but accessing them needs to run the computer with opened enclosure! All high-voltage elements are covered with insulators for your protection but please proceed with extreme caution and use the isolated screwdriver and rubber gloves to protect yourself!

UNIQUE FEATURES & QUALITY

• - Commodore C128DCR compatible (metal desktop case)
• - Stabilized & professionally filtered 5VDC up to 10A output
• - Stabilized & professionally filtered 12VDC up to 5A output
• - 9VAC up to 1.5A line provided by real, heavy duty transformer
• - Active & passive over voltage protection (OVP) for both 5VDC & 12VDC rails
• - Over current protection for all output lines
• - Voltage spikes suppression with ultra-fast TVS diodes
• - Trimmer for 5VDC voltage fine tuning in safe range protected by OVP
• - Trimmer for 12VDC voltage fine tuning in safe range protected by OVP
• - Fully isolated & fused on AC and DC side. 
• - Easy to replace, standard 5x20mm fuses
• - Two auxiliary universal power ports for 5VDC and 12VDC rails (protected by resettable fuses)
• - Universal 0.5m long auxiliary power cables (5VDC & 12VDC) available for order, each terminated with WAGO fastener for easy connection.
• - 115VAC (USA) or 230VAC (Europe) input models
• - Power good status LEDs for 5VDC, 12VDC and 9VAC voltages.
• - Additional advanced output ripple reduction by specially designed filtering circuits
• - Detachable, C128DCR output power cable for easier installation (bundled)
• - 100% repairable, easy to disassemble (preferably by qualified technician), spare parts available
• - All electric cables terminated with the industrial grade, detachable wire-to-board connectors. There's no amateur and dangerous direct AC and DC wire-to-board soldering!

INSTALLATION TIPS:

Always work with AC cable unplugged and connect it only after fitting all the shields and covers back to their original place!

Always connect the ground green/yellow wire (fasten with the screw to the metal shield)!

I suggest to desolder the old AC_L and AC_N wires from the original PSU PCB - instead of cutting them, but if there is no other way - cut as close to the PCB as possible and tin the cable endings to prevent oxidation or at least twist the wire's copper strings together to bind them firmly and avoid short circuits. New AC terminal connector requires no soldering when connecting the original AC_L and AC_N copper wires as shown on photos. I suggest to protect the AC/L and AC/N wires connections once mounted to the terminal and fix them additionally with plastic ZIP band.

Please mind that both old and new PSU are including high capacitance capacitors on high voltage input side. They need to discharge before you may proceed with safe  PSU installation or PSU removal. Please keep the output cable connected (load side) to the C128D main board as long as it's possible to allow discharge. It's recommended to wait 30-60 minutes after power off and main AC cable unplugging for fully discharge. For your protection do not touch the bottom side of the PSU PCB, hold the PCB with the installation holes and PCB outline only.

Mind the output cable colors as the cable supplied with our replacement PSU is using the same color code as the original Commodore PSU fixed cable. Please make sure the polarity is correct when connecting to C128 PCB. See our installation photos and notice the cables orientation in your original Commodore assembly PCB. 

Color codes for the output cable provided:

• white/brown: 9VAC
• black: GND
• red: 5VDC
• yellow: 12VDC

TRUST & RESPONSIBILITY

Every single Electroware PSU unit is triple tested before dispatch. To assure flawless quality and long lasting performance we are testing with original Commodore 128DCR from our collection as well as by burn-in test with customized load simulating devices causing 150% overload comparing to regular Commodore C128DCR computer system.

Stay with the original Electroware products to gain top build quality, unique features unavailable with the clone products.

By purchasing this product you are supporting the retro computing community and contributing to our continuous developing process. Thank you!

WARNING!

Disconnect the main AC power cord to install/uninstall the internal PSU inits. Always use ground connection and the full set of shields and protection covers to avoid the electric shock. Please wait at least hour to discharge the AC capacitors before attempting to disassemble!

Risk of electrical shock and energy hazard when working. All failures should be examined by a qualified technicians only. Risk of fire or electrical shock. The ventilation holes should be protected from foreign objects or dripping liquids. Please do not install power supplies in places with high ambient temperature or close to the heat source. Enclosed power supplies are intent to work in indoor locations, it's not allowed to use power supplies outdoor, in dust or high moisture. Output current and output wattage must not exceed the rated values.

This replacement Commodore 128DCR PSU has been designed to be used with the Commodore C128DCR vintage computer systems and should be considered as an component of Commodore C128DCR computer system. Do not connect to any other devices as it's not a general purpose PSU. Manufacturer is not responsible for any consequences of unauthorized or arbitrary repairs, modifications or incorrect usage. Please notice that new, properly working replacement Commodore C128 DCR PSU is reducing the system's potential fail rate but still is not guaranteeing that entire Commodore C128DCR system will work correctly (as it's over 30 years old).

Stay original! Buy only the genuine C64PSU.com gear and beware the fancy overrated clones flooding eBay & WWW!