Repair Atari Falcon with a dead Keyboard.
Defect:
Repairing:
The defect was caused by a broken track in the third layer of the pcb, thus not visible. Missing the voltage of +5v from the component (L83) towards the pin four of the keyboard connector (J18) (circuit diagram).
I have made a small bridge for fix the problem permanently.
Repairs and calibrations made:
Repairing keyboard Apple ///:
It seems incredible but there is always a button that doesn’t work ;-D
I found on some keyboards of the TI-99/4A the same buttons but with the plunger much smaller. I have used the plunger of the Apple /// button on the TI-99/4a button and i have fixed the problem elegantly ;-D
Thank to my friend Ninetyniner Iuc for the donation of spare parts.
Gallery:
The Apple III (often rendered as Apple ///) is a business-oriented personal computer produced and released by Apple Computer that was intended as the successor to the Apple II series, but was largely considered a failure in the market. Development work on the Apple III started in late 1978 under the guidance of Dr. Wendell Sander. It had the internal code name of “Sara”, named after Sander’s daughter. The machine was first announced and released on May 19, 1980, but due to serious stability issues that required a design overhaul and a recall of existing machines, it was formally reintroduced the following autumn. Development stopped and the Apple III was discontinued on April 24, 1984, and the III Plus was dropped from the Apple product line in September 1985.
The Apple III could be viewed as an enhanced Apple II – then the newest heir to a line of 8-bit machines dating back to 1976. However, the Apple III was not part of the Apple II line, but rather a close cousin. The key features business users wanted in a personal computer were a true typewriter-style upper/lowercase keyboard (as opposed to the Apple II which was based on a teletype keyboard) and 80 column display. In addition, the machine had to pass U.S. Federal Communications Commission (FCC) Radio Frequency Interference (RFI) qualifications for business equipment. In 1981, International Business Machines unveiled the IBM Personal Computer (IBM PC) – a completely new 16-bit design soon available in a wide range of inexpensive clones. The business market moved rapidly towards the PC DOS/MS-DOS platform, eventually pulling away from the Apple 8-bit computer line.
Despite numerous stability issues and a recall that included the first 14,000 units off the assembly line, Apple was eventually able to produce a reliable and dependable version of the machine. However, damage to the computer’s reputation had already been done and it failed to do well commercially as a direct result. In the end, an estimated 65,000–75,000 Apple III computers were sold. The Apple III Plus brought this up to ~120,000. Apple co-founder Steve Wozniak stated that the primary reason for the Apple III’s failure was that the system was designed by Apple’s marketing department, unlike Apple’s previous engineering-driven projects. The Apple III’s failure led to Apple reevaluating their plan to phase out the Apple II, and eventual continuation of development of the older machine. As a result, later Apple II models incorporated some hardware, such as the Apple Scribe Printer, a thermal printer, and software technologies of the Apple III.
source: wikipedia
I have received a Commodore Amiga 500 to use as spare parts. I decided to restore because it’s a ASSY 312512 (Revision 3) with key-switch like IBM chiclet keyboards.
The cleaning took me a whole day but with a great satisfaction at the end of the work. The Commodore Amiga 500 works fine, the floppy drive reads very well and i have added a memory expansion (FAST RAM) of 512k.
Gallery of images (before and after cleaning):
I received the Texas Instruments Expansion System (PEB) from a dear friend.
The Texas Instruments Expansion System (PEB) although fully functional, needs a restoration, for example; some parts of the top and bottom cover are rusty.
Some photos of the work that i have done:
Commodore Amiga 600 (Black Screen) Repair
Defect:
Replaced parts:
Note:
The Amiga 600 Motherboard looks in good conditions; no traces of a acid leakage from capacitors, as usually happens on Amiga 600/1200/4000, but all had a too high ESR (Equivalent Series Resistance).
Atari 7800 ProSystem (NTSC) Repair.
Defect:
Replaced parts:
Yamaha AX-200M MSX (Arabic) ROM Dump (click to enlarge)
Download: Yamaha AX-200M MSX (Arabic) ROM-IC321-27256 (1278)
Perfect – Daewoo MSX 2 (Arabic) Rom Dump (click to enlarge)
Download: Perfect - Daewoo MSX 2 (Arabic) Rom Dump (1353)
Spectravideo SVI-728 MSX (Arabic) Rom Dump (click to enlarge)
Download: SVI-728 (Arabic) ROM-ic48 OKI M27128 Prom (1471)
Commodore Educator 64 Repair.
Defect:
Diagnosis:
Replaced parts:
Working Commodore Educator 64
Commodore Dual Drive Floppy Disk Model 4040 Repair
Defect:
Replaced parts:
Note:
The cause of many problems was the previous repair. It was replaced the voltage regulator LM340K (7812) with a LM338K (Adjustable Regulators). The two components are not compatible and have a different pinout.
Download:
I have adapted a power supply Cisco (P/N 34-0874-01) to be used with the Home Computer Amstrad CPC 6128/664 that use two voltages +5v and +12v (pinout). If you want to use this computer without the original monitor the only way is use a external power supply.
The photo speak for themselves, the modification is very simple. The only thing that i want to say, maybe not everyone knows it, the Cisco power supplies uses the STANDBY remotely, you need to connect together the ROF line with the one of two RTN (GND).
I have also added a third cable in case you want to use an external Floppy Drive.
Gallery:
Tandy Radio Shack TRS-80 Data Terminal (DT-1) Repair.
Defects:
The jobs that have been made:
Radio Shack TRS-80 Model 1 (#2) Repair.
Defect:
Replaced parts:
Radio Shack TRS-80 Model 1 Repair.
This is the second time that this computer was repaired within 2 years.
Defect:
Replaced parts:
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