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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 (225)

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)
 

2 x Commodore Amiga 1200 Recap

December 28th, 2017 No comments
2 x Commodore Amiga 1200 Recap

2 x Commodore Amiga 1200 Recap.

Gallery:

 

Osborne 1 Replaced Capacitors (PSU)

December 28th, 2017 No comments
Osborne 1 Replaced Capacitors (PSU)

This computer did not present the defect described, but knowing well the power supply stage of the osborne, very similar if not the same as the computer series Kaypro, i have preferred to replace the two capacitors that usually present problems.

The real problem came out as soon when i have connected the keyboard, the screen started to flash and the keyboard did not work.

Several pins of the keyboard connector are in short-circuit, i have disassembled the keyboard, unplugged the flat connector and checked the continuity of all pins and everything was perfect.

The problem is the membrane broken in more parts and probably they are some residues inside the keyboard, shaking the keyboard it sounds almost like a maracas.

The membrane of this keyboard can not be replaced because the switches that press the membrane are “hot welded” by melt the plastic, however the membrane is not available as a spare part.

I have tried with the keyboard of my Osborne One (version 1 and 2) and everything works perfectly.

Gallery of the repair:

Sega Game Gear Recap

December 12th, 2017 No comments
Sega Game Gear Recap

Sega Game Gear Recap

Defect:

  • Dead but the Power LED is turned ON.

Repair:

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

Gallery of the repair:

Monitor HP w2228h (replaced Capacitors)

December 4th, 2017 No comments

Sorry, this entry is only available in Italian.

Cleaning/Replacing capacitors Amiga 2000 (REV 4) + PSU

November 22nd, 2017 1 comment
Cleaning and Replacing capacitors Amiga 2000 (REV 4) + PSU

Works that have been made on this Amiga 2000:

  • Replaced the power plug with capacitors inside.
  • Replaced PSU capacitors.
  • Cleaning the motherboard with the toothbrush and PCC Kontakt.

Gallery:

 

Hanimex 2650/Arcadia 2001/Leonardo – Repair & Composite Mod

November 17th, 2017 No comments
Hanimex 2650/Arcadia 2001/GIG Leonardo (loose) Repair & Composite Video Output

Hanimex 2650/Arcadia 2001/GIG Leonardo (loose) Repair & Composite Video Output.

I start to say that this motherboard was not in repair but in one box of  spare parts. I have only the motherboard of this console, no external case, joystick, power supply … totally useless.

Past and present defects:

  • Some time ago the two EMF coils are exploded (see the photo) maybe the capacitor was in short circuit after the two coils
  • Also a capacitors near the coils is disappeared.
  • Black and White video output.

Repair and Video Composite modding:

  • I have bypassed the two coils for the 12v DC.
  • Removed the RF modulator.
  • I have cutted 3 resistors for the video composite output, you can get a better image (contrast and color) (see photo)
  • Replaced a 4066 because are missing two outputs of the R-G-B signal and that’s why the image was in black and white.
  • Added a temporary push button for the RESET.
  • The console without the RF modulator can be powered at 9v DC and not 12v DC, thus avoiding boiling the poor 7805.

Gallery of the repair:

Download:

 

Acetronic (Radofin 1292) MPU-1000 Composite MOD

November 8th, 2017 2 comments
Acetronic (Radofin 1292) MPU-1000 Composite MOD

This Video Composite MOD needs some work unlike other similar consoles, you need to remove a resistor and insert a trimmer, otherwise the Video Composite output signal is really bad.

Works that need to be done:

  • Remove the RF Modulator (remove it completely)
  • Remove the 4.7k Resitor (see photo)
  • Solder a 22k Trimmer between the resistor hole (hole side to pin 8 of the TEA 1002/PE1X) and the ground, the third pin of the trimmer is the Video Composite output. (see photo)
  • Solder a wire for the Audio output. (see photo)
  • Use the same hole of the RF cable for the new video and audio cable.

Before closing everything i recommend to adjust the trimmer for the best Video output.

Gallery of the Video Composite MOD:

3 x Texas Instruments TI-99-4A Repair

November 2nd, 2017 No comments
Texas Instruments TI-99-4A Repair #1

Texas Instruments TI-99/4A Repair (1 of 3)

Defect:

  • Black Screen and deafening sound in background.

Replaced parts:

  • 1 x TMS9900NL CPU (U600)

Personal note that is good for all repairs:

Repairs are done with experience and skill, if there is skill does not mean that there is also the experience.

Repairing any electronic things by desoldering everything to find the bad components is not an index of experience but only ability.

Gallery of the repair:

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Texas Instruments TI-99-4A Repair #2

Texas Instruments TI-99/4A Repair (2 of 3)

Defect:

  • Garbage Screen.

Replaced parts:

  • 1 x TMS4116-15 RAM

Gallery of the repair:

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Texas Instruments TI-99-4A Repair #3

Texas Instruments TI-99/4A Repair (3 of 3)

Defect:

  • Man lacks his legs and miss a piece of rope in the pitfall game demo.

Replaced parts:

  • 1 x TMS9929TML VDC (Video Display Controller)

Gallery of the repair:

Restored the original Amiga A1200 keyboard connector

November 2nd, 2017 2 comments
Restored the original Amiga A1200 keyboard connector

Restored the original Amiga A1200 keyboard connector.

I don’t say anything about the fucking work done before.

Gallery:

Commodore Amiga 500 Power Supply Repair

November 2nd, 2017 No comments
Commodore Amiga 500 Power Supply Repair

Commodore Amiga 500 Power Supply Repair.

Defect:

  • All voltages are unstable.

Repair:

  • Replaced a Zener Diode 5.6V (ZD2). The Diode was corroded and broken, the cause was not the acid of the capacitors.
  • Replaced a Electrolytic Capacitor 1uF 50v (C9) which under voltage don’t work correctly, thanks to the freeze spray i have find it.

All the other electrolytic capacitors have been removed one by one and tested, they are good.

Gallery of the repair:

Commodore VIC-20 (ASSY 250403) Repair

November 2nd, 2017 No comments
Commodore VIC-20 (ASSY 250403) Repair

Commodore VIC-20 Repair.

Defect:

  • Black Screen.

Replaced parts:

  • Replaced MOS VIA 6522 (UAB1)
  • Replaced BASIC ROMS 901486-01 (UE11)

Gallery of the repair:

Commodore 64C (ASSY 250469) Repair

November 2nd, 2017 1 comment
Commodore 64C (ASSY 250469) Repair

Commodore 64C (ASSY 250469) Repair

Defect:

  • Black Screen.

Replaced parts:

  • 2 x NEC D41464D RAM (U10/U11)

Note:

  • The two broken RAMs reached 70 degrees.

Gallery of the repair: