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:

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Chinook Technology RAM 4000: All 4 banks filled for a total of 4Mb.

Gallery:

Apple IIgs Memory Expansion Card. This card has 4 memory banks with a total capacity up to 4Mb (only two banks is presently populated for a total of 2Mb).

The ram that are used for this expansion memory are DRAM HY51C1000LS-10/KM41C1000AP-10.

First of all, I must thank my dear friend Andrea for helping me financially to purchase this interface (one of the last pieces of the third batch).

Unboxing R&D Automation CFFA3000:

This is a CompactFlash / USB flash drive interface for Apple II family of computers.

Specifications:

• Support 1 to 13 partitions under ProDOS and GS/OS, and 2 virtual floppy drives
• Virtual Floppy image support allows the use of almost any non-copy-protected floppy disk image, including .dsk, .2mg, and .nib files. Note: .nib files of protected floppies will not work with the CFFA3000
• Allows storage of thousands of floppy and smartport disk images
• User configurable partition count
• Boot from either device and any partition
• Allow booting from Dos3.3, Pascal, CPM, Contiki, ProDOS or GS/OS directly from the Interface card (for a floppy-less system)
• Configurable as a CFFA smart port controller (i.e. a mass storage device) or as a floppy controller, or both. When configured as both, requires 2 slots in your Apple II, one for the physical card, and one for the virtual floppy controller.
• Hardware supports DMA, although v1.0 software does not currently support DMA. Future support is planned, but not guaranteed.

Apple IIgs through the GBS 8200 v4:

Apple IIgs through the GBS 8200 v4 (display scalar board) to a VGA Monitor.

The cable that i have made takes from the Video Connector of the Apple IIgs the 12v voltage for the GBS 8200.

Schematics:

Video Demostration of CFFA3000 through the GBS 8200:

source: CFFA3000 Homepage

I thank my dear friend that gave me the Z88 Cambridge Computer.

Autopsy:

The Cambridge Computer Z88 is an A4-size, lightweight, portable Z80-based computer with a built-in combined word processing/spreadsheet/database application called PipeDream, along with several other applications and utilities, such as a Z80-version of the BBC BASIC programming language.

The Z88 evolved from Sir Clive Sinclair’s Pandora portable computer project which had been under development at Sinclair Research during the mid-1980s. The machine was launched at the Which Computer? Show on 17 February 1987.

The Z88 is a portable computer weighing 0.9 kg, based on a low-power CMOS version of the popular Zilog Z80 microprocessor. It comes with 32 KiB of internal pseudo-static RAM and 128 KiB of ROM containing the operating system (called OZ). The memory can be expanded up to 3.5 MiB of RAM, the contents of which are preserved across sessions. An integrated capacitor prevents the Z88 from losing its data for the limited amount of time it takes to change the batteries.

The machine uses a membrane keyboard, which is almost silent in use; an optional electronic “click” can be turned on to indicate keystrokes. The Z88 is powered by four AA batteries, giving up to 20 hours of use. It has three memory card slots, which accommodate proprietary RAM, ROM or EPROM cards, the third slot being equipped with a built-in EPROM programmer. Card capacities range from 32 KiB to 1 MiB.

The Z88 has a built-in eight-line, “super-twisted” LCD display, which has greater contrast than conventional twisted nematic LCDs.

source: wikipedia

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 (1469)

This is a test done for a dear friend to check if the Acorn Archimedes A420/I is working properly. The RGB scart cable is homemade by me to connect to a Commodore 1085S monitor.

Gallery:

The Acorn Archimedes was Acorn Computers’ first general purpose home computer to be based on their own ARM architecture. Using a RISC design with a 32-bit CPU (26-bit addressing), at its launch in June 1987, the Archimedes was stated as running at 4 MIPS, with a claim of 18 MIPS during tests. The name is commonly used to describe any of Acorn’s contemporary designs based on the same architecture, even where Acorn did not include Archimedes in the official name.

The first models were released in June 1987, as the 300 and 400 series. The 400 series included 4 expansion slots (although a two slot backplane could be added to the 300 series as an official upgrade, and third parties produced their own 4 slot backplanes) and an ST506 controller for an internal hard drive. Both models included the Arthur operating system operating system (later replaced by RISC OS as a paid-for upgrade), BBC BASIC programming language and an emulator for Acorn’s earlier BBC Micro, and were mounted in two-part cases with a small central unit, monitor on top, and a separate keyboard and three-button mouse. All models featured onboard 8 channel stereo sound and were capable of displaying 256 colours on screen.

Four models were initially released with different amounts of memory, the A305, A310, A410 and A440. The 540 was unveiled in September 1990, and included higher speed SCSI and provision for connecting Genlock devices. The 300 and 400 were followed by a number of machines with minor changes and upgrades.

source: wikipedia

Commodore CBM/PET 3032 Motherboard Repair.

Defect:

• Garbled screen and then “Illegal Quantity Error” message or 31 Bytes free

Replaced parts:

• Replaced 1 x NE555 (A2)
• Replaced 2 x Unstable RAM 4116 (I2/I3)
• Replaced 1 x 74LS153 (E4)

Atari Disk Drive 1050 #1

Defect:

• SIO bus unresponsive.

Replaced parts:

• Replaced 1 x LM3086N (U1)

Atari Disk Drive 1050 #2

Defect:

• SIO bus unresponsive + no reset cycle of the Disk drive on poweron.

Replaced parts:

• Replaced 1 x RAM-I/O-Timer (RIOT) 6532 (U7)

Autopsy Apple IIgs / Keyboard (A2S6000W):

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Autopsy Apple 3.5 Drive (A9M0106):

Autopsy Apple 5.25 Drive (A9M0107):

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Autopsy Apple IIgs Mouse (A9M0331):

Autopsy Apple IIgs RGB Monitor (A2M6014Z):

The Apple IIGS (stylized as IIGS) is the fifth and most powerful model in the Apple II series of personal computers produced by Apple Computer. The “GS” in the name stands for Graphics and Sound, referring to its enhanced multimedia capabilities, especially its state-of-the-art sound and music synthesis, which greatly surpassed previous models of the line and most contemporary machines like the Macintosh and IBM PC.

The machine was a radical departure from any previous Apple II, with its true 16-bit architecture, increased processing speed, direct access to megabytes of RAM, wavetable music synthesizer, graphical user interface, and mouse. While still maintaining full backwards compatibility with earlier Apple II models, it blended the Apple II and aspects of Macintosh technology into one. Keeping with Apple’s “Apple II Forever” slogan of the time, the IIGS set forth a promising future and evolutionary advancement of the Apple II line, but Apple paid it relatively little attention as the company increasingly focused on the Macintosh platform.

The Apple IIGS was the first computer produced by Apple to use a color graphical user interface, as well as the “Platinum” (light grey) color scheme and the Apple Desktop Bus interface for keyboards, mice, and other input devices. It was also the first personal computer to come with a built-in “wavetable” sample-based synthesizer chip, utilizing technology from Ensoniq. The machine outsold all other Apple products, including the Macintosh, during its first year in production.

Apple IIgs booting from Iomega Zip Drive:

source: wikipedia

Autopsy:

The biggest drawback to the Sinclair ZX-81 or Timex Sinclair 1000 computer is its tiny membrane keyboard.

The Memotech keyboard is the solution to this. With its full stroke keys and standard size, it makes entering data and interacting with programs, so much easier. The bus connector had a Memopak I/F keyboard buffer on it so you could type at a natural pace and the Sinclair could keep up with you.

In most cases this keyboard worked right out of the box, but in some cases with older memory packs, you would need to be sure to place the keyboard last in your chain of accessories plugged into the computer’s bus connector and set the dip switches on the keyboard to “slave”.

The membrane keyboard itself is not disabled while the ZX81 Keyboard is connected and either can be utilized for data input… this makes multiplayer, simultaneous play, much easier as each opponent can use their own keyboard as a controller.

source: geekvintage.com