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Archive for the ‘Various’ Category

2 x Texas Instruments TI-99-4A Repair

December 25th, 2018 No comments
Texas Instruments TI-99-4A Repair

Texas Instruments TI-99/4A Repair (1 of 2)

Defect:

  • Black Screen and deafening sound in background.

Replaced parts:

  • 1 x TMS 4732/2532 ROM (U611)

Gallery of the repair:

Texas Instruments TI-99-4A Repair Texas Instruments TI-99-4A Repair

 

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Texas Instruments TI-99-4A Repair

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

Defect:

  • Garbage Screen.

Replaced parts:

  • 1 x TMS4116-20 RAM (U103).

Gallery of the repair:

Texas Instruments TI-99-4A Repair Texas Instruments TI-99-4A Repair Texas Instruments TI-99-4A Repair

 

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DownloadTI99 Technical Manual (47)

Commodore Amiga 600 which has seen better dayz

December 16th, 2018 No comments
Commodore Amiga 600 which has seen better dayz

This Commodore Amiga 600 is arrived in laboratory in immaculate state still with the warranty sticker.

Immediately after the disassembly i have immediately noticed that were are several problems of acid released from the capacitors and dirty that affected this poor Amiga 600 and its Floppy Drive.

A decoupling capacitor it’s exploded with a pit on the PCB side, solved this problem i started to replace all the electrolytic capacitors and to clean the pcb with specific products.

After the replacement of the electrolytic capacitors, i have tried to turn on the amiga that apparently worked, shame about the distorted sound and the floppy drive that read 1 time of 100.

I had to replace the electrolyte capacitor on the Floppy Drive and soon after i looked for the fault of the audio problem that 99% is always the usual LF374.

In this case it was not only LF374 but also a 10ohm resistor that did not let the +12v to the LF374 and a short-circuited ceramic decoupling capacitor.

Components that have been replaced:

  • IC LF374 substituted with a fully compatible TL084C (U15)
  • 10Ohm resistor (R301)
  • 330nF capacitor (C301)
  • 330nF capacitor (C41)

Unfortunately the welding of the LF374 did not come very well how i like to do it but the pad are destroyed and corroded by the acid and they were about to detach, indeed the pad of the pin 2 of the LF374 was really detached, that’s why the pin 1 and 2 of the IC LF374 are connected together, they were connected via the pad.

I leave you to the photos and the video.

Gallery:

Video:

Commodore SX-64 Keyboard Repair & Cleaning

December 16th, 2018 No comments
Commodore SX-64 Keyboard Repair & Cleaning

The Commodore-SX64 keyboard after some time isnt’t responding anymore (all or some keys). In this case, the keyboard needs some cleaning and repair.

First of all you have to disassembly the keyboard housing, pay particular attention to the screws, this plastic is very old and not of a good quality, it breaks only if you look it.

Gently remove the membrane and clean with alcohol all the metal contacts on the keyboard pcb and also clean all the contact pads on the membrane without alcohol.

Next i took some graphite in cream (Keypad Fix) to reconstruct the pads on the membrane by simply applying a very fine layer of graphite on the contacts.

Gallery:

Philips Monitor VS0080 without Audio Repair

December 16th, 2018 No comments
Philips Monitor VS0080 without Audio Repair

This monitor although fully functional in the video section, was missing audio. The integrated circuit of amplifying sound (TDA 2611A) was not powered.

The problem was a broken pcb track (see photo), solved this problem the sound is back.

Gallery:

Video Intercom vintage monitor recycled

December 16th, 2018 No comments
Video Intercom vintage monitor recycled

I received this small Black and White CRT monitor from a friend, Ciro Barile of TI-99 Italian User Club, this monitor was used as a video intercom and i didn’t know the power supply voltage, the pinout but especially if it worked.

Found the pinout and the power supply voltage i saw the image turned upside down, this because the monitor could be hooked both from top and from bottom, nothing could be easier it was enough to change the deflection yoke connector on the motherboard to flip the image.

I drilled two holes on the back of the case to facilitate access to the composite video input and power supply (12v 2A).

Pinout:

  • RED (Video)
  • GREEN (Ground)
  • BLACK (Positive)
  • BROWN (Ground)

Gallery:

Another 2 x Gotek (HXC) with some Enhancements

October 12th, 2018 No comments
Another 2 x Gotek (HXC) with some Enhancements

Another 2 x Gotek (HXC) with some Enhancements.

Enhancements:

  • OLED Display (light blue version)
  • Piezo Buzzer.
  • Rotary Encoder with knob.
  • Firmware HxC by J.F. Del Nero.

Gallery:

Credits for the best firmware Jean-françois Del Nero.

Alternative Cleaner for Floppy Disk 5¼

October 12th, 2018 No comments
Alternative Cleaner for Floppy Disk 5¼

Why throwing away a Commodore Floppy Disk Drive with a broken head it could become a great gadget to clean Floppy Disks.

How to do ? just disassemble the entire part that controls the movement of the head including the head itself.

The power supply used is 12v with at least 1A, you can see the connection in the photo.

Good Cleaning.

Gallery:

Video:

Myarc Geneve 9640 (Replacement filter caps and voltage regulators)

September 12th, 2018 No comments
Myarc Geneve 9640 (Replacement filter capacitors and voltage regulators)

Myarc Geneve 9640 (Replacement filter capacitors and voltage regulators).

I have replaced all the voltage regulators (7805 / 7812) of 1A with the 1.5A version and all the 22uF / 35v filter capacitors.

Will also be installed the missing heat sinks in the geneve with plastic case.

Mattel Intellivision with GSOD (Grey screen of death) Repair

September 12th, 2018 No comments
Mattel Intellivision MOD 5155 (PAL) with GSOD (Grey screen of death) Repair

Mattel Intellivision MOD 5155 (PAL) with GSOD (Grey screen of death) Repair.

Defect:

  • GSOD (Grey screen of death)

Components replaced:

  • 2 x wrong resistors (who has replaced ?!?) of 150 Ohm instead of 300 Ohm.
  • 1 x 74LS00 (burned because the value was wrong of the two resistors)
  • 1 x RAM GTE 3539 UCP (U19)

Gallery of the repair:

Download: Mattel Intellivision Service Manual & Datasheet (138)

Irradio XTC-506R Repaired again

August 21st, 2018 No comments
Irradio XTC-506R -  Repaired again

Irradio XTC-506R Repaired again.

It seems this small Irradio TV/Monitor always suffers from some problem, last time there were short circuits caused by the pressure of the cathode ray tube on the PCB.

This time some cold joints on the solder pads.it would have been very sad to throw it in the garbage trash.

Gallery of the work done:

Nintendo Virtual Boy Repair

August 21st, 2018 No comments
Nintendo Virtual Boy Repair

Nintendo Virtual Boy Repair.

First of all, i thank Andrea Pierdomenico for this fantastic gift.

Below i explain how i have repaired the Nintendo Virtual Boy which show the classic display malfunction problems (both).

I have used only a pencil eraser and a SMD Rework Station to fix the connections of the ribbon cable to the Display PCB of the Virtual Boy.

The process involves heating the connection of ribbon cable to the Display and using a pencil eraser to push segments of the ribbon cable to the PCB.

I configured the hot air station to 145 Degrees and 55 of Air Pressure and i made 3 fast transition without ever stopping at a specific point, pressing between one pass and another with the pencil eraser.

It Works!

Gallery of the work done:

UAV Video Upgrade for Atari Computers & Consoles

August 12th, 2018 No comments
UAV (Ultimate Atari Video) Video Upgrade for Atari Computers & Consoles

UAV (Ultimate Atari Video) Video Upgrade for Atari Computers & Consoles.

This circuit improves the signal video output and allow to use both output (SVIDEO and COMPOSITE). The circuit is compatible with all Atari 2600, 5200, 7800 consoles and all Atari Home Computers 400, 800, 1200 …

I thank my friend Charlie for giving me this circuit that i have immediately installed in my Atari 2600 Jr which i use with the Harmony SD Cartridge.

NOTE:

Don’t use the socket in place of the IC 4050 as seen in the photo. The external case of the Atari 2600Jr console is too thin and cannot be closed anymore.

Gallery of the work done:

source: atariage.com

Mean Well T-60B Power Supply for Amiga

August 12th, 2018 No comments
Mean Well T-60B PowerSupply for Amiga

Mean Well T-60B switching power supply put in a box to be used for Amiga computers.

This is a nice summer job for my friend Andry.

Gallery of the work done:

Download: Mean Well T-60B datasheet (198)

Another Gotek (HXC) with some Enhancements *updated*

August 5th, 2018 No comments
Another Gotek (HXC) with some Enhancements

Another Gotek (HXC) with some Enhancements.

Enhancements:

  • OLED Display
  • Piezo Buzzer
  • Push Button for select
  • Rotary Encoder

Gallery:

Video:

Credits for the best firmware Jean-françois Del Nero.

ZOE rev 2.0 Inty (Mattel Intellivision) RGB Interface for sale now!

July 29th, 2018 2 comments

Available for sale the ZOE RGB rev 2.0 interface for Mattel Intellivision.

The Zoe interface lets you connect the PAL Mattel Intellivision console to a TV/monitor through the RGB signal of a SCART connector, dramatically increasing the quality of the video signal and bringing it to the highest possible quality: the original output is a modest RF/Antenna signal.

The interface is connected in place of the National LM1886 IC (TV Video Matrix DAC) to take the RGB and Sync signals and convert them for the SCART output.

Below some examples of video quality using a Sony PVM9041QM CRT Monitor and a Sony KD-49XD8305

The ZOE rev 2.0 interface is tested individually piece by piece before shipment.

The assembled kit is available and you can buy it now from ebay or privately (An installation service on the console will be available for less experienced users)The kit includes:

  • 1 x ZOE rev 2.0 pcb with 3 bioadhesive supports.
  • 1 x Dupont connector to the 8-pin DIN female panel socket (30cm long)
  • 1 x Flat cable to connect the ZOE RGB to the socket of the LM1886  (19cm long)
  • 1 x SCART Cable to 8-pin DIN male (2mt long)
  • 1 x Audio cable with dupont connector from one end and to solder on the other side (30cm long)
  • 1 x Precision IC Socket to replace the LM1886.
  • 2 x Screws to fix the 8-pin DIN female.

Video test (Italian Only):

The video was made by a friend Vincenzo Sinceri.

If someone wants to remake the din-scart cable (example: more length), this is the pinout:

Download: Zoe RGB rev 2.0 Interface Installation Manual (English/Italian) (199)

If you have problems to viewing in the correct way the manual in PDF format click here for the instruction how to configure the Adobe Acrobat Reader.