Archive

Archive for the ‘Projects / Repairs’ Category

Phase5 CyberStorm MK2 @ 100Mhz (040 Hack – Stable)

March 18th, 2018 2 comments
Phase5 CyberStorm MK2 @ 100Mhz (040 Hack - Stable)

Phase5 CyberStorm MK2 @ 100Mhz (040 Hack – Stable)

This is a simple hack to overclock the Cyberstorm MK2 at 100Mhz without needed adapters or simply replacing the oscillator which causes instability or malfunctions.

The hack consists downgrading the Cyberstorm MK2 to 040 simply by moving the two resistors can you see marked in the photos.

For some CPU or MK2 models it is also advisable to replacing the original voltage regulator LT1085CM at 3.3v with this one LT912CM 3.5v but if the amiga is stable after hours of operation you can also avoid the replacing the voltage regulator.

Gallery of the work done:

source: Cosmos Blog

Commodore Amiga 4000 – 64Mb Fast Memory Hack

March 18th, 2018 No comments
Commodore Amiga 4000 - 64Mb Fast Memory Hack

Commodore Amiga 4000 – 64Mb Fast Memory Hack.

The Amiga 4000 motherboard can be ´hacked´ to handle 64Mb of Fast Memory (4 SIMM modules of 16 MB each)

To do this, you have to solder a new GAL and make some bridges between FASTRAM SIMM -> GAL -> CHIP RAMSEY.

This work is not complicated but you need to have a good practice with the soldering iron and PLCC soldering.

Gallery of the work done:

Download: Amiga 4000 64Mb Hack (702)

source: Cosmos Blog John Hertell Blog

Upgrading Commodore A3640 CPU Card (part two)

March 18th, 2018 No comments
Upgrading Commodore A3640 CPU Card (part two)

Upgrading Commodore A3640 CPU Card (part two)

I have replaced the CPU 060 EC version with a 060 FULL with FPU REV 1.

When using the adapter with a non EC version of the 060 you must also use a fixed version of the kickstart v3.1 with the exec.library modified to support the FPU.

Gallery of the work done:

Download: Kickstart v3.1 Exec Patch Version for 3k & 4k - Ready to Burn! (780)

Upgrading Commodore A3640 CPU Card (part one)

March 18th, 2018 No comments
Upgrading Commodore A3640 CPU Card (part one)

Upgrading Commodore A3640 CPU Card (part one)

Works that have been done:

  • Upgrading GAL (U204 & U209)
  • Socket for Oscillator.
  • Overclocking.
  • Replacing all capacitors (the recap was already done but for the CPU adapter 040 -> 060 was necessary use smd capacitors for the little space available)
  • CPU Adapter 040 -> 060.
  • CPU Motorola 68EC060

Gallery of the work done:

Amiga 4000 repair with Floppy Drive that is not recognized

March 18th, 2018 No comments
Commodore Amiga 4000 repair with Floppy Drive that is not recognized

Commodore Amiga 4000 repair with Floppy Drive that is not recognized.

Defect:

  • Floppy Drive Dead (not recognized)

Repair:

  • Replace CIA 8520 (U300).

Gallery of the work done:

Commodore Monitor 1084S-P Repair

March 5th, 2018 No comments
Commodore 1084S-P Repair

Commodore Monitor 1084S-P Repair.

Defect:

  • Completly dead with only a loud whistling noise in background.

Repair:

  • Replaced the flyback transformer (AT2079/30102) everything has started to work perfectly.
  • It’s mandatory to made a calibration of the SCREEN and FOCUS with the two trimmer placed on the rear side of the flyback transformer.

Note:

A loud whistling noise indicates a bad flyback transformer (also known as an LOPT).

Gallery:

Download: Commodore Monitor 1084S-P Schematics (318)

Commodore CBM 8032 – Motherboard Repair (ASSY 8032030)

February 11th, 2018 No comments
Commodore CBM 8032 (HP Early version [1980]) Motherboard Repair (ASSY 8032030)

Commodore CBM 8032 (HP Early version [1980]) Motherboard Repair (ASSY 8032030)

Defect:

  • Garbage screen.

Repair:

  • Replaced 4 x 2114 Static RAM (UC4 / UC5 / UC6 / UC7)

Note:

As you can see from the photos this computer is already been repaired by a butcher. The butcher did not use the sockets after replacing the static ram ones and the pads had already suffered from the previous desoldering and soldering, probably using an unsuitable soldering station.

Gallery of the repair:

 

Commodore CBM 8032 – PCB Monitor Repair (ASSY 321448)

February 11th, 2018 No comments
Commodore CBM 8032 (HP Early version [1980]) PCB Monitor Repair (ASSY 321448)

Commodore CBM 8032 (HP Early version [1980]) PCB Monitor Repair (ASSY 321448)

Defect:

  • Dead. Missing High Voltage from Flyback Transformer (LOPT)

Repair:

  • Replaced 2 x burned resistors of 56Ohm 1/4w (R752 / R753)

… and now let’s move on to the second defect. :-)

Gallery of the repair:

 

GIG Leonardo Composite Mod

January 16th, 2018 No comments
GIG Leonardo Composite Mod

Video Composite modding:

  • Removed the RF modulator.
  • Removed one pin of the 3 resistors (see photo) for the video composite output, you can get a better image (contrast and color) (see photo)
  • I have used the same hole of the RF cable for the composite video and audio cable.

Gallery of the Video Composite mod:

 

Sega Game Gear (Boxed) Full Recap

January 1st, 2018 No comments
Sega Game Gear (Boxed) Full Recap

Sega Game Gear (Boxed) Full Recap.

Defect:

  • Dead but the Power LED is turned ON.

Repair:

  • Replaced all capacitors (Main / DC-DC / Audio)

Gallery of the repair:

Commodore 64C (ASSY 250425) Repair

January 1st, 2018 No comments
Commodore 64C (ASSY 250425) Repair

Commodore 64C (ASSY 250425) Repair.

Defect:

  • Basic Screen without text and prompt.

Replaced parts:

  • 1 x MT 4264-20 RAM (U24)

Gallery of the repair:

 

Texas Instruments TI-99-4A Repair

January 1st, 2018 No comments
Texas Instruments TI-99-4A Repair

Texas Instruments TI-99/4A Repair.

Defect:

  • Cartridges port doesn’t work.

Fix:

  • Cleaning the cartridge connector (computer side) with one pin oxided.

Gallery of the repair:

 

Texas Instruments Modulator PHA2036 Repair

January 1st, 2018 No comments
Texas Instruments  Modulator PHA2036 Repair

Texas Instruments Modulator PHA2036 Repair.

Defect:

  • After a few seconds of use the image becomes dark until it disappears completely.

Repair:

  • The problem was inside the RF modulator. After removed the problem is gone. If you made the composite mod i always recommend to removing the Modulator.

Roland MT-80s Repair

January 1st, 2018 No comments
Roland MT-80s Repair

Roland MT-80s Repair.

Defect:

  • Working good but without sound.

Repair:

  • Fixing the two solder pads broken of the bridge rectifier for the 13v.

Gallery of the repair:

Download: Roland MT-80s Service Manual (181)

Video Test:

Commodore VIC-20 (ASSY 250403) Repair

December 28th, 2017 No comments
Commodore VIC-20 (ASSY 250403) Repair

Commodore VIC-20 (ASSY 250403) Repair

Defect:

  • Black Screen.

Replaced parts:

  • Replaced CPU 6502 (UE10)