Gallery:

Epson PX-4+ Easy Repair

Defect:

• Dead.

Replaced parts:

• Replaced 1 x Fuse 3A

Removed the internal Backup Battery (RB 301) 4.8v 90mA.

Commodore VIC-20 Repair

Defect:

• Black screen … then black and white image.

Replaced parts:

• Replaced 1 x 901486 KERNEL ROM (U12)
• To fix the problem of the image in black and white i have adjusted the “RED” trimmer (C48)

Commodore 16 Power Supply Repair

Defect:

• Output voltage in short circuit.

Replaced parts:

• Replaced 1 x 4700uf / 16v Electrolytic capacitor.
• Replaced 1 x 800mA Bridge rectifier.

Atari 2600 Repair

Defect:

• The second joystick port doesn’t works properly.

Replaced parts:

• Replaced 1 x 6532 RAM-I/O-Timer (RIOT)

Commodore CBM 4032 (40 Columns) Repair

Defect:

• “Device not present” error when using the IEEE 488 port (Example Floppy Drive)
• Sometimes the computer show the prompt of the TIM monitor (Machine Language Monitor program)

Replaced parts:

• Replaced 1 x IC 6522 VIA (UB15)
• Replaced 1 x IC 6520 PIA (UB16)

This Commodore PET 2001-8C also includes a homemade Power Amplifier to hear the sound of some games that use the pin CB2 of the User Port as audio output.

Also is included a reset button and two mini-led (Red / Green) that display the data (Save / Load) when using the tape recorder.

Some photos of the Commodore PET 2001-8C:

Copyright label on the motherboard:

Some photos of the repairing and cleaning:

Commodore PET 2001 (Chicklet) Repair datassette.

Defects:

• Doesn’t load any more.

Repair:

• Replace motor.
• Replace belt.
• Azimuth adjustment.

Thanks to Manosoft for the spare parts (white datassette, the same model of the black one)

Commodore PET 2001 (Chicklet) Repair.

Defects:

• Wrong chars on the screen.
• Memory problems.

Repair:

• Replaced all MOS 6550 main ram with an 6550 Ram Adapter by xAD & Manosoft (only 2 x MOS 6550 was faults)
• Replaced 1 x MOS 6550 Video Ram with a spare one from the main ram.

Video of Galaxy Invaders with Sounds:

from Wikipedia homepage:

The Commodore PET (Personal Electronic Transactor) was a home/personal computer produced in 1977 by Commodore International. A top-seller in the Canadian and United States educational markets, it was Commodore’s first full-featured computer, and formed the basis for their entire 8-bit product line.

Read more…

Gallery:

Restoration the external case of the Micro Peripherals Ltd Floppy Disk Drive that was eaten by rust.

Gallery:

Cleaning the keyboard keys is really tedious.

Gallery:

12►

Commodore CBM(PET) 4032 (FAT40) / 8032 Cathode Ray Tube (CRT) Replacement.

The cathode ray tube was taken from the Amstrad GT-65 (Monochrome monitor)

The CRT Tube Orion 310GNB31 (Amstrad GT-65) is fully compatible with the Amperex M31-334GH (CBM 4032/FAT40 – 8032).

NOTE: The same CRT work perfectly for the computer Radio Shack TRS-80 Model 3 and Model 4.

Gallery of the repair:

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

Defect:

• Blue Screen with tiny Vertical lines.

Replaced parts:

• 1 x MCM6810P (128 x 8-Bit Random-Access Memory TTL/DTL)

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

Defect:

• Blue Screen with tiny Vertical lines.
• Wave/Raster Lines.

Replaced parts:

• 2 x IC MCM6810P (128 x 8-Bit Random-Access Memory TTL/DTL)
• 1 x IC CD3236A-NL (ROM)
• 1 x Capacitor 12 pF.

Note:

In one photo you can see the curious change made in this TI-99/4A by inserting a resistor in the pitch where in other motherboards is soldered a leg of a electrolytic capacitor and then one leg of the capacitor is welded and the not the other leg.  Compliments.

Video of the defects:

Gallery of the repair:

Repair Commodore Amiga 600 (White Screen)

Defect:

• White Screen.

Replaced parts:

• 1 x LM555 (SMD)
• 1 x Electrolytic Capacitor 10uf 25v

Note:

I have thought it was a problem of RAM (U17) since i have measured oddities but the problem instead is a capacitor of 10uF, dead LM555 (smd) and some pcb tracks corroded.

Repair Philips 8220 (MSX2) Black Screen with Sound.

Defect:

• Black Screen but with sound (keyboard works)

Replaced parts:

• 2 x Fuse 250v 315ma
• 4 x Tantalum Capacitor 22uf 6v
• 1 x Electrolytic Capacitor 100uf 25v

Note:

The main problem was caused by the lack of +12 volts that power the RGB Encoder module. The other voltage of -12 volts are used only for the cartridges port (but not all cartridges using this voltage)

I wanted to do a experiment to install a standard PC drive with a adapter (34 pins to 14 pins) on a Philips 8245. I would say that it work but i have tried about 20 Floppy Drives and only 1 it works ;-D

Gallery:

Download: Philips NMS 8245 (MSX2) Floppy Drive replacement (1307)

source: msx.hansotten.com

Gallery of the repair:

Phonola NMS 8245 (MSX 2) Repair.

Defect:

• Dirty characters/graphics.
• Floppy Drive dead.

Replaced parts:

• 1 x 41464 Video RAM (U16)
• 1 x Floppy drive belt

Other:

• Frame cartridge connector fix for a easy removal of the components under the frame.

Removing the filter capacitors that are exploded inside the Astec power supply of a Apple //e.

Gallery of the repair and cleaning: