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 (1086)

source: sourceforge.net

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 (974)

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 (1178)

source: wikipedia

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 (1178)

source: wikipedia

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

Titles:

• The Wasps and the Apples +T
• Petscii-Poker
• Petscii Poker &D
• Time of Silence V1.0
• Midnight Resistance +8DFHR
• Chest Bump 101% +MF
• Sprint 1 +2H
• Motorman Preview +M
• Lorella +3ME
• Vendetta [easyflash]
• Quadrant 4 +2
• Quadrofender +5  
• Athanor Preview
• The Evil Dead +3DGMH
• Storm Warrior +3D
• Scorched Earth Preview
• Wizard Saga Preview 2 +2
• The Last Breakout +
• Quadrofender +5F
• Gameboy Tetris V2 Preview +J
• Dragon’s Cave +19D
• Quadrant 4 +2F
• U91306 – Eidothea – The Daughter of Protheus [seuck]
• Zamzara Preview Pack +6
• Quod Init Exit v1.5
• The Soul Gem of Martek Preview +D
• Sunburst +14D
• Gulp!! And Arrow Graphics &D
• Jump Ninja Preview +
• Mining +2D

Download: All Games in One Archive (3982)

source: csdb.dk

Sorry, this entry is only available in Italian.

The Home Computer Asem AM 100 is a clone of the Apple II+ (Apple // Plus). This computer was manufactured and assembled by ASEM S.p.A. Artegna (UD) / Italy.

The AM 100 is fully compatible with all the software available for the Apple II and II+. I have personally tested many programs and i’ve never found problems of compatibility.

Unfortunately this computer is arrived faulty, the repair was more simple than i expected, thanks to the IC sockets located on the computer motherboard.

Works that have been made:

• Replacing IC 74LS161 which shows a vertical band on the screen.
• Removing RIFA filter capacitor located inside the PSU.
• 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
• General cleaning of the case outside/inside, monitor and keyboard.
• EPROM dump.

All these works are documented with photos that you can find below.

Gallery repairs:

12►

Under the cover gallery:

12►

Final photos:

Interesting discovery:

Inside the Floppy Drive reader (Apple clone) i have found the same mechanics (Mistumi / Newtronics) of the Commodore Floppy Drive 1541. See the first three pictures of the gallery: Under the cover.

Download: ASEM AM 100 full Eprom Dump (1189)

Tynemouth Software PET microSD & PET ROM-RAM-Tester replacement boards

PET ROM-RAM-Tester:

This is a board which plugs into the 6502 CPU socket on something like a Commodore PET and can selectively replace the onboard ROM (it includes a test software) or RAM.

PET microSD:

Disk drive replacement for Commodore Pet range of computers, the 2001, 3000, 4000 and 8000 series. It also works with vic-20/c16/Plus4/c64/128*

*IEEE-488 adapter required.

You can buy these boards from here.

Packaging:

source: tynemouthsoftware.co.uk

UK1541 is a real time drive emulator with cycle-exact 6502 instructions execution and VIA’s emulation just by tiny MCU, LCP1114, Cortex M0, 48Mhz (0,84 DMIPS/Mhz).

Developed by Krzysztof Switajski aka Kisiel/ICON.

Features:

• LCD TFT Screen 2,2“ , 320 x 240, True Color.
• MSP430.
• LPC1114.
• Infra Red receiver, for remote control.
• CR2032 battery holder.
• Mini jack connector as replacement for IEC port.
• DB9 connector for joystick.
• User Port connector, for power and signals like 8-bit parallel aka burst.
• Two buttons , MENU and RESET.

Features for the latest Core Version (1.1.4.012015):

• Core 6502 running at 1Mhz with illegal opcodes – 16kB Flash ROM, multiple custom roms not available now
• 4KB Ram, from $0000 till $0fff
• VIA port and timers emulation
• SD card 1 – 8GB, FAT32, formatted in Windows.
• d64 35 / 40 track with read and write (beta testing)
• Update from standard SD card.

Gallery:

source: wiki.projekt64.filety.pl

Forth, the Language.

Forth is a different language. It’s aged and a little weird.
What’s cool about it? It’s a very low-level and minimal language without any automatic memory management. At the same time, it easily scales to become a very high-level and domain-specific language, much like Lisp. Compared to C64 Basic, Forth is more attractive in almost every way.

It is a lot more fast, memory effective and powerful. Compared to C, specifically cc65, the story is a little different. It’s hard to make a fair comparison. Theoretically Forth code can be very memory efficient, and it’s possible to make Forth code that is leaner than C code. But it is also true that cc65 code is generally much faster than Forth code.

Download: durexForth v1.4.3 + Manual (993)

source: csdb.dk

Commodore VIC-20: latest games from VIC-20 Denial forum.

Download: All Games in One Archive (1488)

source: VIC-20 Denial Forum