The KIM-1, short for Keyboard Input Monitor, was a small 6502-based single-board computer developed and produced by MOS Technology, Inc. and launched in 1976. It was very successful in that period, due to its low price (following from the inexpensive 6502) and easy-access expandability.

The KIM-1 consisted of a single printed circuit board with all the components on one side. It included three main ICs; the MCS6502 CPU, and two MCS6530 Peripheral Interface/Memory Devices. Each MCS6530 comprises a mask programmable 1024 x 8 ROM, a 64 x 8 RAM, two 8 bit bi-directional ports, and a programmable interval timer. The KIM-1 brochure said “1 K BYTE RAM” but it actually had 1152 bytes. The memory was composed of eight 6102 static RAMs(1024 x 1 bits) and the two 64 byte RAMs of the MCS6530s. In the 1970s memory sizes were expressed in several ways. Semiconductor manufacturers would use a precise memory size such as 2048 by 8 and sometimes state the number of bits (16384). Mini and mainframe computers had various memory widths (8 bits to over 36 bits) so manufacturers would use the term “words”, such as 4K words. The early hobbyist computer advertisements would use both “words” and “bytes”. It was common to see “4096 words”, “4K (4096) words” and “4 K bytes”. The term KB was unused or very uncommon. The KIM-1 was introduced in the April 1976 issue of Byte magazine and the advertisement stated “1 K BYTE RAM” and “2048 ROM BYTES”.

Also included were six 7-segment LEDs (similar to those on a pocket calculator) and a 24-key calculator-type keypad. Many of the pins of the I/O portions of the 6530s were connected to two connectors on the edge of the board, where they could be used as a serial system for driving a Teletype Model 33 ASR and paper tape reader/punch).

One of these connectors also doubled as the power supply connector, and included analog lines that could be attached to a cassette tape recorder.

Earlier microcomputer systems such as the MITS Altair used a series of switches on the front of the machine to enter data. In order to do anything useful, the user had to enter a small program known as the “bootstrap loader” into the machine using these switches, a process known as booting. Once loaded, the loader would be used to load a larger program off a storage device like a paper tape reader. It would often take upwards of five minutes to load the tiny program into memory, and a single error while flipping the switches meant that the bootstrap loader would crash the machine. This could render some of the bootstrap code garbled, in which case the programmer had to reenter the whole thing and start all over again.

The KIM-1 included a somewhat more complex built-in Terminal Interface Monitor software called TIM that was “contained in 2048 bytes of ROM in two 6530 ROM/RAM/IO arrays”. This monitor software included the ability to run a cassette tape for storage, drive the LED display, and run the keypad. As soon as the power was turned on, the monitor would run and the user could immediately start interacting with the machine via the keypad. The KIM-1 was one of the first single-board computers, needing only an external power supply to enable its use as a stand-alone experimental computer. This fact, plus the relatively low cost of getting started, made it quite popular with hobbyists through the late 1970s.

Gallery:

Download: Commodore-MOS KIM-1 Docs (1206)

 source: wikipedia

Brief summary of NOT repairing the Commodore Chessmate of a dear friend (Giacomo Vernoni).

The Chessmate I received had a funny defect: it worked for 10-15 seconds and then freezed completely with harrowing sounds in the background. So the defect appeared when something warmed up.

Having another Chessmate (mine) to compare the signals to, I noted right away that communication was missing between RIOT (6530) -> ROM (6332) -> CPU (6504) -> RAM (AM9111); CLOCK and RESET were working fine.

I sprayed synthetic ice on the 6530 RIOT to check if the problem was caused by this IC: as a matter of fact, after lowering its temperature, the Chessmate began to work again. I was glad I found the problem, but quite unhappy because the spare part is almost impossible to find. To double check I decided to unsolder the 6530, install a socket, and try it on my Chessmate.

It worked! Damn… after thinking about it for a while, I thought that maybe the spray partially freezed the nearby ROM too.

So I reinstalled the 6530 back in the non-working Chessmate, I turned it on, and after 15 seconds I sprayed the synthetic ice on the 6332, and it magically worked again.

That’s it… from that moment on, the Chessmate always worked! after the freezeing spray I left the Chessmate turned on for two hours and it never stopped working.

So, I’m asking myself: did the ice repair the ROM? Will it die again? probably yes :-D Maybe there was some small tin residue on the PCB that I removed by spraying it: I noticed that the Chessmate had already been repaired before, there were visible signs on the pcb.

It will remain a mystery, anyway the MPS 6322 ROM can be replaced by a 2532 EPROM (pinout compatible) or by a 2732 EPROM with an adapter.

Gallery:

This is a program that can playback .SID files found in the HVSC collection on a real Commodore 64/128.

You will find different versions of SP64 in this package, most of themwill work on all devices.  But I suggest you use the correct version for for your device, since they might contain special commands.

Versions of the program:

• sidplay64-reu-1541u2cmd.prg – 1541 Ultimate II version with REU.
• sidplay64-reu-sd2iec.prg – SD2IEC version with REU.
• sidplay64-reu-1541u-netdrive.prg – 1541 Ultimate & Netdrive with REU.
• sidplay64-reu-iec-cmd-ide64.prg – CMD drives, IDE64 devices & other IEC devices, with REU.
• sidplay64-reu-normal.prg – REU version for 1541, 1571, 1581 and clones of these.
• sidplay64-normal.prg – Standard version for 1541, 1571, 1581 and clones.
• sidplay64-1541u-netdrive.prg – 1541 Ultimate & Netdrive.
• sidplay64-iec-cmd-ide64.prg- CMD drives, IDE64 devices & other IEC devices.
• sidplay64-sd2iec.prg – SD2IEC.

(The 1541U2 software iec mode has been disabled for this build.)

Download: SIDPlay 64 (SP64) v1.0.0 (1186)

source: sourceforge.net

The Multiface 128 by Romantic Robot UK Ltd  is a true multi purpose interface with:

• Fully universal and 100% automatic BACK-UP facility for tape, microdrive, Discovery, Plus D or Disciple.
• 8K RAM extension – suitable for our GENIE, LIFEGUARD, or as a buffer, etc.
• MULTI TOOLKIT to study/modify/develop programs, POKE infinite lives, etc.

Gallery:

Download: Multiface 128 User Manual (1797)

source: worldofspectrum.org

The Opus Discovery 1 is a true disk drive system for your Spectrum. 250K floppy drive and interface. Video output port (monochrome). Joystick port. Peripheral Through port. Parallel printer port.

Gallery:

Opus Discovery 1 + ZX Spectrum 48k Blue Fairy version :D

Download:

• Opus Discovery 1 Manual (English) (2451)
• Opus Discovery 1 Manual (Italian) (1305)

source: worldofspectrum.org

Regeneration of the Keyboard PAD.

Some keys did not work properly. The Keyboard PAD have been regenerated using a suitable product that can be found for sale on eBay. Try: KEYPAD FIX

Gallery of the fix:

CBM prg Studio Version 3.5.0 is released. There are a lot of new features in this version. I’d really appreciate it if you report any bugs you find or have any suggestions/comments.

CBM prg Studio allows you to type a BASIC or Machine Code program in using a nice Windows environment and convert it to a ‘.prg’ file which you can run on an emulator, or even a real C64 / VIC20 or PET if you’re feeling brave and have the right kit.

CBM prg Studio is the result of merging C64PrgGen and VIC20PrgGen. Adding new features and fixing bugs in two apps which were 95% similar was a bit of a nightmare so merging them made sense.

It was also a good opportunity for a face lift and to add some new features, such as:

• Programs are project based, meaning all related source files, sprite files etc. are kept in one place and multiple source files can be linked more easily.
• Tabbed MDI.
• Syntax highlighting.

What CBM prg Studio isn’t is a front-end for tok64, cbmcnvrt, bastext or any other tokeniser / detokeniser / assembler. It’s all been written completely from scratch.

Improvements:

• Assembler:
  • Reporting of page boundary crossings for branching instructions.
  • Choose character set for TEXT directive.

• General:
  • Editing tools (Select to end/start of screen/doc etc.)
  • Comment blocks

• Debugger:
  • Show effective address of next instruction.

Bugs Fixed:

• Assembler:
  • Low of high byte of labels could fail.
  • Occasionally wrong target machine type with ‘generate and launch.’
  • Problems with a comment character after a comment character or in a string.
  • Problem with a label as a destination when the label is on the same line as the macro definition.
  • ‘Align’ incorrect when already on align boundary.

• Debugger:
  • Wrong return address shown.

• BASIC:
  • Statistics tool not coping with ‘rem’ in strings.

See the help for a complete list of new features and fixed bugs.

Note In this version, each target machine can have its own default project directory. If you are upgrading from a previous version (before version 2.5.1) of CBM prg Studio you may be asked to set up your project directories again. Your current projects will not be affected.

Download: CBM prg Studio v3.6.0 (1090)

source: ajordison.co.uk

The Commodore 2031 and Commodore 4031 are single-unit 5¼” floppy disk drives for Commodore International computers. They use a similar steel case form to the Commodore 9060/9090 hard disk drives, and use the IEEE-488 interface common to Commodore PET/CBM computers. Essentially, both models are a single-drive version of the Commodore 4040.

The Commodore 2031LP is functionally the same as the 2031, but used the lower-profile tan case of the second version of the Commodore 1541 floppy disk drive intended for home computer use.

These drive models use a single-density, single-side floppy data storage format similar to that used by the Commodore 1540 & Commodore 1541 drives, but with a slightly different data marker indicating which model originally formatted the disk. The low-level disk format is similar enough to allow reading between models, but different enough that one series of drive models cannot reliably write to disks formatted with one of the other model series. A different of one extra ‘header’ byte is what causes this write incompatibility.

Gallery:

Comparison Commodore Floppy Drive 2031 (Low Profile) & 2031 (High Profile):

Fix the Commodore Floppy Drive 2031 (High Profile)

Removed the filter capacitors RIFA in the power plug.

Download: Commodore Floppy Drive 2031LP/HP Rom (1314)

source: wikipedia

Like the Pig do not throw anything away.

Recovered components:

• 2 x KM416C254 (256K x 16Bit CMOS Dynamic RAM with Extended Data Out)
• 10 x KM48C2104 (2M x 8Bit CMOS Dynamic RAM with Extended Data Out)
• 5 x HYB514171 (256k x 16Bit Dynamic RAM)
• 2 x Piezo Buzzer
• 1 x NE556 (GENERAL PURPOSE DUAL BIPOLAR TIMERS)
• 1 x EZ1085CM (3.0 AMP POSITIVE VOLTAGE REGULATOR)

Gallery:

There is nothing simpler than burning the Kickstart ROM at home :D

Gallery:

Below you can download the Amiga Kickstart 3.1 rom already ready for programming, the only thing that you have to do is the “Byte Swap” with your programming EPROM software.

Download: Amiga 500/600/1200/2000/4000 Kickstart 3.1 ROM + Docs (688)

NOTE: Download REMOVED (DMCA infringement)

Replacing electrolytic capacitors Commodore Amiga 600/1200.

Gallery full Recap 2 x Commodore Amiga 1200:

Gallery full Recap 1 x Commodore Amiga 600:

All computers that i use for experiments or tests must at least be cleaned and disinfected.

Works that have been made:

• General and accurate cleaning.
• Accurate cleaning with a magnifying lens of the AMIGA logo with isopropyl alcohol. I have used also a toothpick to remove the black color from the corners.
• Full Recap of the motherboards.
• Removed the two pieces of metal.
• Fixed the RGB video connector (totally broken).
• Replaced the keyboard with another one less yellowed.
• Added a Gotek Floppy Drive with HXC Firmware.
• Kickstart ROM 3.1.

Photo gallery before cleaning:

Photo gallery after cleaning:

Repair Motherboard (ASSY 326298) Drean Commodore 64

Defect:

• Black Screen.
• Missing Video Signal.

Cause of the Missing Video Signal:

• The motherboard of this C64 to work with the PAL-N video (Argentina) has been modified. Some pcb tracks are cut off and the modulator has been replaced. There are also a few bridges to retrieve the S-VIDEO output (luma / chroma).

Video Restoration:

• I have made a bridge with a wire for recover the composite signal that has been removed (tiny blue wire).

Repair:

• The cause of the black screen are 2 x MK 4564 ram in short circuit.

Photo gallery of repair:

The Commodore 2031 and Commodore 4031 are single-unit 5¼” floppy disk drives for Commodore International computers. They use a similar steel case form to the Commodore 9060/9090 hard disk drives, and use the IEEE-488 interface common to Commodore PET/CBM computers. Essentially, both models are a single-drive version of the Commodore 4040.

The Commodore 2031LP is functionally the same as the 2031, but used the lower-profile tan case of the second version of the Commodore 1541 floppy disk drive intended for home computer use.

These drive models use a single-density, single-side floppy data storage format similar to that used by the Commodore 1540 & Commodore 1541 drives, but with a slightly different data marker indicating which model originally formatted the disk. The low-level disk format is similar enough to allow reading between models, but different enough that one series of drive models cannot reliably write to disks formatted with one of the other model series. A different of one extra ‘header’ byte is what causes this write incompatibility.

Gallery:

Repair/Restoration Commodore Floppy Drive 2031LP

Defect:

• Lock lever of the Floppy Drive broken.
• When the Floppy Drive is powered up, red LED stays on and spindle motor runs continuously.

Repair/Restoration:

• Replaced the Lock lever with a new one taken from a Commodore Floppy Drive 1541 (spare parts)
• Replaced the ROM (UAB5 901484-05) with a EPROM MCM 68766 supplied from my friend Giacomo Vernoni.

Note:

The Eprom programming was done with a EPROM programmer Promenade by Jason-Ranheim Co. for Commodore 64.

Repair/Restoration Gallery:

Download: Commodore Floppy Drive 2031LP/HP Rom (1314)

source: wikipedia