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:

I start to saying how much i hate repairing psu switching, one of the most boring things second only to the repair of CRT Monitor, at least for me.

However this repair was made. The failure is almost certainly caused by a copious spillage of electrolyte (conductive fluid usually formed from a salt solution or acid which is located inside of the electrolytic capacitors) and a dangerous test if the machine works again after the electrolyte was leaking over the pcb.

The moral of the story is easy to figure out, a short circuit has made several deaths, a good portion of the Primary (PWM) and Secondary.

The components that have been replaced are the following:

• 1 x Electrolytic Capacitor 3300µF 16v 105°
• 1 x Electrolytic Capacitor 1000µF 25v 105°
• 1 x Electrolytic Capacitor 2200µF 35v 105°
• 1 x Electrolytic Capacitor 1000µF 100v 105°
• 1 x Electrolytic Capacitor 330µF 160v 105°
• 1 x Electrolytic Capacitor 47µF 25v 85°
• 1 x Electrolytic Capacitor 10µF 100v 85°
• 1 x Electrolytic Capacitor 22µF 25v 85°
• 1 x Sanken Hybrid Voltage Reculator Module STR 53041
• 1 x Photocoupler TLP 541G
• 1 x Overcurrent Protection Elements ICP N10
• 1 x Transistor C1815GR
• 1 x Transistor DTC114 ESA (C114 ESA)

After 1 week i have decided to replace also all capacitors of the power supply section of the computer.

Components replaced:

• 1 x Electrolytic Capacitor 3300µF 25v 105°
• 3 x Electrolytic Capacitor 5600µF 10v 105°
• 1 x Electrolytic Capacitor 2200µF 10v 105°
• 1 x Electrolytic Capacitor 330µF 35v 105°
• 1 x Electrolytic Capacitor 1000µF 16v 105°
• 1 x Electrolytic Capacitor 470µF 25v 105°
• 1 x Electrolytic Capacitor 1µF 50v 105°

Gallery of the repair:

12►

Gallery:

This is a full replacement of the power supply of the Amiga 500 with a similar one of the last generation. This type of switching power supply fits perfectly inside the case of the original psu.

The repair will not be made because this psu is very common at very low prices, i don’t waste even a second to find the multiple faults, i prefer devote to other things less common.

Commodore Floppy Drive 1541 Motherboard #1

Defect:

• IEC bus unresponsive.

Replaced parts:

• Replaced 1 x VIA 6522 (UC3)

Commodore Floppy Drive 1541 Motherboard #2

Defect:

• IEC bus unresponsive.

Replaced parts:

• Replaced 1 x VIA 6522 (UC3)
• Replaced 1 x 7414 (UA1)
• Replaced 1 x 901229 ROM (UB4)

Removed parts:

• SpeedDos adapter with the flat cable (user port bus) cutted.
• SpeedDos ROM Adapter.

Sinclair QL #1 Repair

Defect:

• White Screen (RAM problem)

Replaced parts:

• Replaced 3 x 4264 RAM

Note:

I took the opportunity to install the Minerva Rom v1.98 to identify the faulty ram. Thanks to the Minerva ROM i have identified 2 of 3 Ram failed.

• Ram Location $1F340 (IC9)
• Ram Location $3D040 (IC10)
• Ram Location $30910 (IC16)

Sinclair QL #2 Repair

Defect:

• White Screen / Black Screen / Garbage Screen / Annoying Background Sound

Replaced parts:

• Voltage regulator (7805) fault. In input we have 9v and in output 9v instead of 5v.

Note:

Incredibly nothing is exploded ;-D

Commodore Amiga 500+ #1

Defect:

• Battery Leaks.

Solution:

• Battery Removed.
• Cleaned the PCB with PCC Kontakt.

Commodore Amiga 500+ #2

Defect:

• Battery Leaks.

Solution:

• Battery Removed.
• Cleaned the PCB with PCC Kontakt.

Commodore Amiga 600

Defect:

• Where are the capacitors and the tracks ?

Solution:

• Cleaned the PCB with PCC Kontakt.
• Alternative way to install the capacitors ;-D

Commodore A500 Keyboard: Keep the useful things from the useless things.

Commodore Amiga 500 Keyboards Join & Fix.

Unfortunately from five keyboards i have made only one in a good shape and full working.

Commodore Amiga 500/600 PSU Repair

Amiga 500/600 (PSU) PowerSupply #1

Defect:

• Short-circuit and the fuse blows.

Replace parts:

• 1 x Transistor NPN 2SC3679.

Amiga 500/600 (PSU) PowerSupply #2

Defect:

• Short-circuit and the fuse blows.

Replace parts:

• 1 x Transistor NPN BU508A.

Amiga 500/600 (PSU) PowerSupply #3

Defect:

• Short-circuit and the fuse blows.
• The PCB is half broken.
• Some components have suffered of too much heat.
• The locking pins of the cover are broken.
• Dirty and Yellowed.

I don’t made the repair. I recovered what might come in handy.

Gallery:

The Gotek is a USB Floppy Drive emulator very cheap, you can buy it from eBay at €24.00 €20.00 including the shipping cost.

Let’s start by saying that this Floppy Disk Emulator with the original firmware is totally useless for our purpose, like to connect it to an Amiga and in the near future to a Atari ST or Amstrad CPC. The new firmware written by Herve Messinger replaces the original firmware, to do this you need a simple converter from USB to TTL Serial Interface to program the STM32 ARM Cortex MCU.

I would add this thing; this Floppy Drive Emulator is not absolutely comparable to the HXC Floppy Emulator of Jean-François DEL NERO (Jeff) where in addition to supporting dozens of Floppy Formats/Hardware and the Firmware is in development from several years but it’s a nice and inexpensive alternative.

For more information, firmware and programming tool you need to go here the official blog of Herve Messinger.

Video:

source: cortexamigafloppydrive.wordpress.com

Gallery:

Commodore SX64 Keyboard Fixed.

Defect:

• Some keys works and some not.

Work done:

• Cleaning with a “Contact Cleaner” to remove the oxidation of gold contacts under the membrane.
• Cleaning all keys.
• Cleaning the keyboard case (inside/outside).

Gallery:

Replacement NiCd Battery of a Commodore SR4190R Calculator.

Defect:

• Battery Leaks.

Replaced parts:

• Replaced 3 x NiCd Rechargeable Batteries 1.2v.

Gallery:

Commodore SX64 (USA/NTSC) Repair.

Defect:

• Black screen and then noise of a misaligned drive (don’t read anything).

Replaced parts:

• Replaced 1 x 906114 PLA (UE4)

Other things:

• Aligned the Floppy Drive using the original copy of the Free Spirit Software Drive Alignment.
• Removed the broken switch to disable the write protection and disconnected a LED on the front side of the SX64.
• Connected the sensor wires cut.
• Cleaning the Floppy Drive.

Apple IIc Rom v4 Upgrade & Repair.

Defect:

• The second RAM in the auxiliary memory is faulty.

Replaced parts:

• Replaced 1 x RAM 4264 (ARD1)

Upgrade:

• Apple IIc ROM upgraded to the latest version V4 (MON)

Download:

• Apple IIc v4 ROM + Installation Manual (1473)