2 x Commodore Amiga 600 Full Recap and Repair

April 10th, 2016 No comments

2 x Commodore Amiga 600 Full Recap and Repair.

Commodore Amiga 600 #1:

  • Full SMD Capacitors Recap.
  • Replaced the joystick port with a missing two pins. The joystick port has been recovered from a pcb (not amiga) for spare parts.


Commodore Amiga 600 #2:

  • Full SMD Capacitors Recap.


TRS-80 Model 1 L2 – Video Snow Shovel Hardware Fix

April 10th, 2016 2 comments
TRS-80 Model 1 L2 - Video Snow Shovel Hardware Fix

TRS-80 Model 1 L2 – Video Snow Shovel Hardware Fix

Video snow, the black streaks against white characters, is most apparent with large, rapidly changing areas of white graphics. The root of the problem is that the TRS-80 display is memory mapped by the CPU.

The solution is to give the video circuitry higher priority than the cpu.


On my TRS-80 Model 1 where i use the Quinnterface & FreHD i had to use the version that also includes the 74LS125 which seemed optional but in this case it does not appear to be optional, we have to do it, otherwise doesn’t work.

Thanks to Ian Mavric for the support.

Gallery of the hardware mod:

Download: 80 Microcomputing Magazine 1982 (217)

TRS-80 Model 1 L2 – Lowercase characters Hardware mod

April 10th, 2016 No comments
TRS-80 Model 1 L2  - Lowercase characters Hardware mod

One of the most famous limitations of the TRS-80 Model I was its inability to display lower case characters.

Although the lower case characters were present in the character set, the Model I lacked the extra memory chip needed to store the bit corresponding to lower case.

The significance of this limitation has been exaggerated over time (it is worth noting that at that same time the Apple II also lacked lower case), but it created a real problem for word processors. Many lower case upgrades for the Model I were created to address the omission, ranging from simple to more complex.

The TRS-80 video display uses a dedicated block of 1024 bytes of memory located in memory space at 3C00 Hex. When received from the factory, there are only 7 memory chips installed in this block of memory, providing 128 possible characters for screen display. The stock TRS-80 uses 64 of these combinations for graphics and a second 64 for the upper-case subset of the ASCII character set. Bits 0-5 control the character selection, and the highest bit (bit 7) is used to determine if the character is alpha-numeric or graphic. Bit 6 is missing!

To add lower-case display, bit 6 must be implemented. This may be accomplished by switching the memory chip for bit 7 to bit 6, thereby enabling lower-case letters and eliminating graphics, or by addition of an 8th memory chip. We prefer adding the extra chip. In either case, if you plan to use Level II BASIC, you must include a switch to disable bit 6, or BASIC will place a lot of funny characters on the screen!

Gallery of the hardware mod:

Download: Lowercase characters Hardware mod (251)

source: trs-80.org

TRS-80 Model 1 L2 – Assembling Quinnterface & FreHD Interface

April 10th, 2016 No comments
TRS-80 Model 1 L2 - Assembling Quinnterface & FreHD Interface

TRS-80 Interfaces in KIT from Ian Mavric and J. Andrew Quinn.

I begin to assemble the kit:

  • “Quinnterface” is a Mini Expansion Interface for TRS-80 Model I with 16K. Neat little device is perfect for Model I users who own a 16K Level II unit (which is most of you) but no EI or Disk Drives, and don’t want to modify your Model I with upgraded boot Rom or memory upgrade. The Quinnterface, developed by J. Andrew Quinn from New Zealand, adds 32K RAM and auto-boot functionality to your FreHD.
  • “FreHD” SD Card HARD DRIVE Emulator for TRS-80 Model I/III/4.

The complete kit consists:

  • Quinnterface.
  • FreHD.
  • Model 1 Hard Drive Adapter.
  • BoHx. A small neat enclosure for your FreHD!
  • CD ROM / Stickers and Cables.


source: ianmav.customer.netspace.net.au/trs80/

Sinclair Microvision MTV1B

April 6th, 2016 No comments

This is a Sinclair Microvision MTV1B. It’s the second attempt of Clive Sinclair’s to make a small portable television.

Released in 1978, it was the smallest television in the world with a CRT tube. A teeny-tiny 2″ D5-100w CRT made by Telefunken. Powered by 4 x AA or via External Powersupply at 6v DC (Negative at the center of the power connector).


Download: Sinclair Microvision MTV1B Schematics (261)

Luxor ABC 80 (Boxed)

April 6th, 2016 No comments

The ABC 80 (Advanced BASIC Computer 80) was a home computer engineered by the Swedish corporation Dataindustrier AB (DIAB) and manufactured by Luxor in Motala, Sweden in the late 1970s (first model August 1978) and early 1980s. It was based on the Zilog Z80 running at 3 MHz and had 16 KB RAM, expandable to 32 KB, and 16 KB ROM containing a fast semi-compiling BASIC interpreter.

ABC 80 normally used a dedicated (included) tape recorder for program and data storage, but could also be expanded to handle disk drives (and many other peripherals). Some sound effects could be produced by a Texas Instruments SN76477 sound chip which was connected to an 8-bit output port, but there was no way to control the chip’s features in any detail, so sound was limited to 96 fixed sounds. The monitor was a black and white TV set modified for the purpose (an obvious choice since Luxor also made TVs). The computer had excellent I/O response times, something that was discovered when trying to upgrade to personal computers. The solution was to use a microcontroller that communicated with a PC. The main unit had a reset button as well.

ABC 80 was also manufactured on license as BRG ABC80 by Budapesti Rádiótechnikai Gyár in Hungary. It used the same keyboard, but the case was metal instead of plastic.

The ABC 80 was a huge hit in Sweden, and grasped a majority share of the rising personal computer market thanks to its office software in Swedish. Although the ABC 80 fans would defend the ABC 80 by referring to its good BASIC and usable extension bus, it couldn’t defend the home market against the gaming computers with color graphics and better sound that arrived in the early 80s like the Commodore 64, even though a new cheaper version was released that could use an ordinary TV instead of the dedicated video-monitor.

Luxor held on to its office market for a couple of years longer with the ABC 800 series, which had a more extensive BASIC, more memory and a 512×240 ‘high-resolution’ graphics mode, but otherwise similar performance. In 1985 Luxor also tried to compete in the office market against the IBM PC with its ill-fated ABC 1600 and ABC 9000 series UNIX computers, but failed.


… and the boxes

source: wikipedia

Repair Luxor ABC 80 *updated*

April 6th, 2016 No comments
Luxor ABC 80 Repair


  • Some keyboard keys are totally dead.
  • Missing +17v and obviously the +12v
  • Short-circuit on the psu side, inside the monitor.
  • Tape Recorder with the mechanism stucked.


  • Replaced most of the Tantalum Capacitors* on the main pcb and on the tape recorder pcb, some are in short-circuit.
  • Replaced 1 x Fuse on the CRT Monitor pcb side.
  • Repair Tape Recorder, i had to disassemble most parts of the tape recorder mechanism. The lubricant grease was dry and has totally blocked the mechanism of the tape recorder.
  • Replaced all pads (Foam Mylar Pad) of the Keytronics Keyboard, the same Keyboard used in SOL-20.

* For this repair i have used only tantalum capacitors, although i usually prefer to use electrolytic capacitors, i used to keep the same aesthetic.

Gallery of the repairing:


It was a Commodore Amiga 2000 – Black Screen of death – Repaired

April 5th, 2016 1 comment
Commodore Amiga 2000 - Black Screen of Death #1

Commodore Amiga 2000 – Black Screen of death

The Battery Acid has corroded some pcb tracks (not visible to the naked eye) connected to the pin of the resistor packs RP900 and to MC68000 and probably other IC.

Gallery before cleaning and repair:

Commodore Amiga 2000 – All that glitters is not gold.

After some work it seems to work but still suffers of some problems.

Present problems:

  • All Connectors are rusty and uprooted.
  • Boot sequence problems, when boot correctly, there are no problems.

Resolved issues:

  • Corroded tracks, i have made 12 bridges*.
  • Replaced “deflowered” kickstart socket.
  • Replaced not working Kickstart 1.2 ROM.
  • Replaced 4 x LM33256 (RAM) shorted.

I need to assess whether or not continuing with the repair…

Big gallery of the repairing:

Welcome back, Commodore Amiga 2000.

I do it very shortly, i don’t like writing a lot because i don’t  have time to do and i don’t like it.

We are left with the Amiga 2000 that sometime works and sometime not.

Defect/Boot Errorr code was: gray / yellow / green / rainbow / out of sync / purple / white.

When this not happen, the boot works perfectly and i can see theusual “hand”

  • To fix the problem of the green screen that indicates problems of the RAM, i had to replace 3 x LM33256 (Total RAM replaced: 7), these ram are not shorted but partially functional and 1 x 74LS244.
  • To fix the problem of the yellow screen which created problems with the LATCH, i had to replace a 1 x 74LS373.

I have also replaced the socket of the MC68000 CPU and i have discovered another interruption between the pitche and track and also a lot of corrosion and recovered some connectors of an old Amiga 2000 REV 4 motherboard to give an decent aesthetic look to the repaired motherboard.

Now the Commodore Amiga 2000 works perfectly.

Before and after Gallery:

Commodore CBM 4008

April 5th, 2016 No comments
Commodore CBM 4008

The Commodore PET 4000 series features Basic 4.0 as a standard feature, along with more memory and a lower price that made them attractive to schools.

Elementary, Middle, and High Schools all over Canada and the United States were filled with these impressive lumbering beasts. Introducing children far and wide to the wonders of BASIC programming. Another lesson taught was the importance of patience, since many schools provided only a tape datasette for loading and saving work.

Like the other models of PET, the 4000 series includes dual datasette ports, though only one is exposed to the outside of the casing. A standard IEEE-488 interface in the back allows the PET to connect to the numerous (and heavy) disk drives and printers being produced by Commodore and other manufacturers.

The PET also has a fully programmable bi-directional parallel interface called the “User” port, which allows the PET to connect and control almost any device one could dream up! The greatest feature, however, is the friendly READY prompt, and the well-laid out keyboard with graphic characters only a keypress away! Pictured here is the PET 4016.

Interestingly, although Commodore provided 8, 16, and 32k versions of their PET 2001 and 3001 series, they had a hard time getting people to purchase higher memory versions as an upgrade. It seemed that people were soldering in their own memory chips onto PET 2001 and 3001 8k and 16k models to upgrade them to 32k. To help prevent this, Commodore sold many PET 4008 and PET 4016 models with the empty memory sockets punched out and destroyed! This encouraged those who wanted more memory to upgrade to the 4032 instead of doing it themselves.


source: zimmers.net

C4CPC cartridge replacement for the Amstrad Plus range & GX4000

April 5th, 2016 No comments
C4CPC cartridge replacement for the Amstrad Plus range and the GX4000

C4CPC is a cartridge replacement for the Amstrad Plus range and the GX4000.

Using a micro-SD card storing cartridge images it also allows direct loading of the cartridge from a PC (Windows/Linux/OSX) through USB.


  • Direct access to 16 cartridges selected by dip switches. Cartridge can be up to 512kB.
  • Access to unlimited number of cartridge images using the provided selector cartridge.
  • Direct cartridge loading from host computer using USB.
  • Cartridge file can be in standard .cpr format or raw binary .bin
  • Integrated ACID.


Download: C4CPC GX4000 microSD Games & Demos (220)

source: cpcwiki.eu

Commodore VIC-20 Repair

April 5th, 2016 No comments
Commodore VIC-20 Repair


  • Black screen.

Replaced parts:

  • Soldered a 24-pin IC socket.
  • Replaced 1 x 901486-07 KERNEL ROM (UE12)

Gallery of the repairing:

Commodore SX-64 USA (NTSC) – Repairing and Cleaning

April 5th, 2016 No comments
Commodore SX-64 (USA)

A big disappointing this Commodore SX-64 USA purchased for spare parts to fix aesthetically one of my SX-64 PAL.

Why disappointing? because from the photo’s looked in a very bad shape, rust stains, various diseases and not working.

Conversely after removed the shit from the external case, replaced the booring PLA (906114), general cleaning + keyboard / Floppy Drive test and replaced one keyboard lock, the SX-64 is fully working and aesthetically in good condition.

Now i have for myself four SX-64 where the fourth is NTSC/USA, but honestly i was not looking for the USA version.

I am really unlucky :D

Gallery of the cleaning and repairing:

C64 Big Game Pack: Alone Against the BSE9 +6T / QWAK +3F …

April 4th, 2016 No comments

Some new games or tools (Cracked / Trained or Unrealeased) for Commodore 64 have been released from your favorites groups.


  • Speeding on the A 81 +7
  • Speeding on the A 81 + Bonus
  • Slime Deluxe +3
  • Lazarian +3DGH
  • Fire-Drill +H
  • Pirati +2DT
  • Petaco´5
  • Mini-Penetrator +3HT
  • Sheepoid – Frozen in Time +4DF
  • Sheepoid – Frozen in Time
  • Slider Session
  • Kill the Bit
  • Frogger II – Three Deep +4D
  • Castle of Life +3DT
  • West +2DT
  • It’s Magic 2 +4PI
  • Movement Basic
  • Shockway Rider +6DGH
  • Pothole Percy +3D
  • Buttonpress
  • Chopper Hunt +3
  • Heathcliff +DGMF
  • Ring on a String [16kb cartridge]
  • Slime Deluxe [16kb cartridge]
  • T.H.E.A. [16kb cartridge]
  • Alienator [16kb cartridge]
  • Vortex Crystals [16kb cartridge]
  • Pickle’s Pod Patrol [16kb cartridge]
  • Icicle Race [16kb cartridge]
  • Platman [16kb cartridge]
  • Bug Hunt [16kb cartridge]
  • QWAK [16kb cartridge]
  • Blap ‘n Bash Revisited [16kb cartridge]
  • Platman +4
  • Pickle’s Pod Patrol +4H
  • Night of the Valkyrie [seuck]
  • Ring on a String
  • Platman +2H
  • Icicle Race +2
  • QWAK +3F
  • Bug Hunt +1H
  • Blap ‘n Bash Revisited +5HD
  • Alienator +4HF
  • Vortex Crystals +9HD
  • T.H.E.A. +2D
  • Ring on a String +
  • Alone Against the BSE9 +6T

Download: All Games in One Archive (297)

source: csdb.dk

Revision 2016 – C64 Party results

March 29th, 2016 No comments

This is the official demo party results from Revision 2015 (Top 3 Entries only). See also the CSDB Revision 2016 section for more informations.

C64 4K Intro:

  • 1 – The Best Intro Ever by Razor 1911.

Mixed Graphics:

  • 6 – Vote EvilBot by Laxity.

Mixed Music:

  • 4 – 8-bitburgers by Panda Design.
  • 5 – A Computer in My Backpack by Lft.
  • 9 – Remembrance by Genesis Project.

Mixed Demo:

  • 1 – We Are Demo by Fairlight, Noice, Offence.
  • 6 – Watch My Balls in Action! by Singular.
  • 7 – Decrunch 2016 Invite by DreamWeb.

Download: Revision 2016 Party stuff (269)

source: 2016.revision-party.net

CBMXfer v0.41.1 (Front-End for CBM4Win/CBMLink/ZoomFloppy)

March 17th, 2016 No comments

CBMXfer is a front-end to several command-line utilities for transferring files and working with disk images. CBMXfer makes using those utilities easy by providing a familiar windows interface that removes the need to learn the commandline syntax of each program. CBMXfer also includes a multi-format file and picture viewer.

The commandline utilities are:

  • OPENCBM – transfers files/images to/from a real CBM drive connected via an ‘X-cable’ on the parallel port.
  • CBMLINK – transfers files/images to/from a real CBM drive connected to a real CBM computer connected to the PC via a serial cable.
  • C1541 – a utility from VICE that works with CBM Image Files (ie: D64,D71,D81 files).
  • NIBTOOLS – Utilities to transfer images via parallel port. Supports protected disks.
  • IMGCOPY – Utility to image IEEE and 1581 disks.

What can I do with it?

  • Transfer files to or from real CBM drives
  • Create D64 and other images files from real CBM disks
  • Write D64 and other files back to real CBM disks
  • Transfer files from WITHIN Image Files
  • View Commodore files (BASIC, SEQ, Binary, ML, Chr Sets, and Images). Supports all all machine types
  • ML viewer is a full two-pass symbolic disassembler!
  • Simple file operations like copy, delete, rename
  • Launch VICE and attach disk images plus autorun
  • Zoom Floppy supported.
  • Supports 1581 partitions with OpenCBM
  • Format disks
  • Supports IEEE drives with Zoom Floppy

Download: CBMXfer v0.41.1 (292)

source: Steve J. Gray Homepage