Commodore Amiga 500+ Replace Keyboard Membrane

Defect:

• 50% of the keyboard keys are totally dead.

Replaced parts:

• 1 x Keyboard Membrane.

Gallery of work that was done:

Conversion Amiga 500 REV 8A (512k Chip RAM) to 500+ (1MB CHIP Ram)

Some Amiga 500 sold at the end of 1991/beginning of 1992 have a motherboard of an Amiga 500+ but limited to the capabilities of a regular Amiga 500 with 512k of Chip RAM.

These motherboards can be converted to 500+ simply installing the missing pieces; RAM section and REALTIME CLOCK.

What i did is add a 512K to have 1MB of Chip RAM like the amiga 500+.

Gallery of work that was done:

Chinon FB-354 ReCAP (Amiga Floppy Drive)

Defect:

• Don’t read anything – Dead.

Replaced parts:

• 3 x Electrolytic Capacitors of 22uF.
• 1 x Electrolytic Capacitor of 1uF.

Gallery of work that was done:

Panasonic JU-253-043P ReCAP (Amiga Floppy Drive) #1

Defect:

• Don’t read anything – Dead.

Replaced parts:

• 1 x Electrolytic Capacitor of 10uF.

Gallery of work that was done:

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Panasonic JU-253-043P Replace Micro Switch (Amiga Floppy Drive) #2

Defect:

• The Floppy Disk is not recognized.

Replaced parts:

• 1 x Micro Switch.

Gallery of work that was done:

Teac FD-235F ReCAP (Amiga Floppy Drive)

Defect:

• Don’t read anything – Dead.

Replaced parts:

• 3 x Electrolytic Capacitors of 22uF.
• 1 x Electrolytic Capacitor of 4.7uF.

Gallery of work that was done:

Hyperkin Supaboy S – RGB/Svideo HACK

I have decided to make this hack because the native video output of the Hyperkin Supaboy S is really bad, uses the composite video.

The photos with the LCD monitor use the SVIDEO output while the photos with the Sony CRT monitor use the RGB output.

The photos and the schematic describe very well the work that needs to be done, the hack is not complex but you always have to be makes particularly attention to the SMD (CXA 1645M) side welds.

RGB/Svideo Schematics:

Gallery of the work that was done:

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Philips Videopac+ G7400 RGB/Composite Hack – Repair – Recap

I have received a gift from my dear friend Andrea Pierdomenico a Videopac+ G7400 console with the BASIC Microsoft module and some cartridges that go into my collection of videopac cartridges.

This console running smoothly but with some problems.

• Power button not working (as usual)
• A capacitor of the power supply section has a broken leg.

The works that have been made:

• Replacing the power switch with a compatible one.
• Full recap of the power supply section.
• RGB/Composite HACK for unparalleled video output.
• RF Module Removal.
• Shifted the 220V Power Cable into the hole of the RF antenna.
• Two video cables (Composite-Audio / RGB-Audio)

Videopac+ G7400 RGB/Composite Hack (components that need to be added):

All the works that have been made are documented in the photos below:

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source: g7400 guide rgb mod

Texas Instruments Magic Wand Speak & Learn Fixed

Defect:

• Doesn’t always turn on.The power button doesnt work properly.
• Battery acid leak.

Fix:

• Cleaning the Battery acid leak in the battery compartment.
• Cleaning the strange power-on button with a spray Contact Cleaner R-11.
• Inserted a thicker on the power-on button because the plastic pin that pressing the contact has deteriorated.

Note:

• External power supply 6v (TIP POSITIVE)

Gallery:

Cartridge shell for FinalGROM 99 – TI-99/4A

I have fit in a best way the pcb of the FinalGROM 99 inside a standard cartridge shell of a TI-99/4a game.

As you can see from the photos the final result is good, there are still some minor imperfections but i’m very satisfied.

I have made three cartridges shells, one for me and two for my friends Ciro Barile of  TI-99 Italian User Club, Andrea Pierdomenico.

Some things about the FinalGROM 99:

The FinalGROM 99 supports ROM images, GROM images, and mixed images of up to 1 MB in size that use the write-to-ROM bank switching scheme. The cartridge does not require the Peripheral Expansion Box and runs on both PAL and NTSC consoles, including modified consoles with an F18A. It will also run on v2.2 consoles and enables those to run ROM-only programs.

The cartridge offers some advanced modes that provide RAM and GRAM to programs. It also allows a running program to reload another program from SD card or to dump its state to SD card. All firmware of the FinalGROM 99 can be updated by SD card.

FinalGROM 99 is released as Open Source Hardware under the CERN OHL license and the GNU GPL license. Both hardware design files and firmware sources are available on GitHub.

For more information about this project please visit the project homepage hosted at GitHub.

Gallery of the works that have been made:

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Download:

• FinalGROM99 SD CARD Utility/Games Compilation (880)

Commodore 128D Repair #1

Defect:

• Black Screen.
• Garbage Screen.

Replaced parts/Fix:

• 9v AC line Fuse of the PowerSupply.
• Made a bridge of a pcb trace interrupted.

Gallery of the repair:

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Commodore 128D Repair #2

Defect:

• Garbage Screen.
• Memory Problems.

Replaced parts:

• Replaced 74LS08 (U61)
• Replaced OKI M3764A [RAM] (U43)

Gallery of the repair:

Commodore Floppy Drive 1541 (ASSY 250442) Repair

Defect:

• Drive access problems (IEC): drive resets but the computer freez with a “searching for”

Replaced parts:

• Replaced EL74S14 with a 74LS14 (UA1)

Gallery of the repair:

Commodore 16 Power Supply Repair

Defect:

• Dead.

Replaced parts:

• Replaced Electrolytic Capacitors of 4700uF/16v
• Replaced Fuse of 250v/1A Retarded.

Gallery of the repair:

Commodore 16 Repair #1

Defect:

• Black Screen.

Replaced parts:

• Replaced RAM TMS4416 (U6).

Gallery of the repair:

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Commodore 16 Repair #2

Defect:

• Black Screen.

Replaced parts:

• CPU Socket (U2).

Note:

I took advantage of this repair to install the ic sockets on the entire motherboard and use it like a “test board” for repairs.

Catweasel Z-II Mk2 (Urine CAT Cleaning)

Defect:

• The card is not recognized by the computer.

Cleaning:

• The Catweasel has traces of cat urine that with time has crystallized causing corrosion and short circuits.  I used the KONTACT PCC & Toothbrush to clean. I also checked the continuity in holes between pcb layers and traces in general.  Now it seems to work properly.

Gallery of the repair:

Peggy Plus (Scala MD100) v1.1 Recap

This Z2 card for Amiga has a problem of audio distortion on one channel. I have replaced all the tantalum capacitors, two of them in the Audio section.

Unfortunately i could not try this card, i did consider that could be also a problem of the NE5532  a Dual Low-Noise Operational Amplifier so i preferred put it on a socket, so it’s easy to replace if it is needed.

Gallery: