Easy trick to improve a little bit the video quality for the Commodore 64.

The fix can be made without removing the modulator. Obviously the RF output doesn’t work anymore.

Gallery:

Hex file for upgrade/mod the Vogatek A51099 Arcade Supergun 16F505 controller chips by MCJ Design 2007

Installation instruction:

• Simply program the hex file onto 2 * Microchip PIC16F505 chips.

Features:

• Press “A” on Megadrive/Genisis controller on the first power-up (this fixes random key outputs if the 2nd Controller is not used).
• PCB mod (detailed photo in the archive). Press Start + C to add coin/credit.

Gallery of the firmware upgrade:

Download: Hex file for upgrade/mod the Vogatek A51099 (1013)

Repair Sinclair Spectrum +3 Power Supply

Defect:

• Dead.

Problems:

• All pad of the transformer output are broken.
• Broke the fuse holder and therefore the fuse it moves inside the power supply.

Repair:

• I have made bridges to restore the connection between the pcb and the transformer.
• Replaced the fuse holder.

Gallery of the repair:

Someone has to do this tedious job and also i advise you do not postpone the capacitors replacement.

Macintosh Recap:

• 1 x Macintosh Portable
• 1 x Macintosh SE (battery removed)
• 1 x Macintosh LC520
• 1 x Macintosh Color Classic

Gallery of the Macintosh Recap:

A new donation from Paolo Cognetti.

Donated items:

• ZX Spectrum + (Complete/Boxed) with keyboard problems
• Philips MSX Printer VW-0010
• Philips MSX QuickDisk VY-0002
• Apple II/II+ Joystick
• ABT Apple II+ External Keypad
• ZX Spectrum + Manual
• SCSI Iomega ZIP Drive + Cable
• Some ZX Spectrum Tape Cassette
• Macintosh Plus Motherboard
• Some PCMCIA Cards

Thanks Paolo.

Repairing Radio Shack TRS-80 Model 1 ..for the third time

Defect:

• SHIFT keyboard switch broken.
• Garbage Screen on boot (already repaired).
• Flat cable of the Keyboard broken (already repaired)

Repair:

• Replaced the keyboard switch with a new one taken from a keyboard (the good one) of the Texas Instruments TI-99/4A that helps me many times.
• Replaced a 2102 Video SRAM.
• Rebuilt the keyboard flat cable.

Gallery of he repair:

We had a few problems yesterday with the firewall which has caused a bit of site downtime. We’re very sorry now the problem was fixed.

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 v1.5.2 + Manual (1017)

source: csdb.dk

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 v1.5.1 + Manual (981)

source: csdb.dk

Jungle King Coin-op – Taito Original – Insert Coins Workaround-Fix

Defect:

• The game works only in Demo mode because doesn’t work the insert coins switch.

Solution:

• I followed a guide that i have found online where recommend to cut the pins 3-4-9-10 of the IC 74LS08 (IC28) which is just below the little ROM PCB (no bootleg). This problem or bug is present on both version, original or bootleg of Jungle King.

Gallery:

source: wiki.aussiearcade.com.au

The HxC Floppy Drive Emulator is a software and hardware system created by jfdn aka Jeff.

The aim of this project is to replace the floppy disk drive by an electronic device emulating the floppy disk drive (list of supported Computer/Hardware).

There are two differents emulators:

• A USB version which allows to connect the floppy disk drive interface of the computer to a PC via a USB cable.
• A SDCARD version which allows to emulate floppy disks which images are stored in a SDCARD.

Release notes for the HxCFloppyEmulator software v2.1.4.0:

• New Loader : *.ANA AnaDisk file loader.
• New Loader : VFDDAT file loader.
• New Loader : Densei Sirius VFD DAT Loader.
• New Writer : *.DIM writer.
• New Writer : *.ADZ writer.
• New Writer : *.TRD Writer.
• New Loader : Atari ST *.STW Loader.
• New Writer : Atari ST *.STW Writer.
• New Writer : Atari ST *.ST Writer.
• New Writer : Atari ST *.STX Writer.
• STX Loader/Writer : Flakey bits mask support added, Loader/writer improved.
• SCP Loader/Writer : Loader/writer improved.
• D88 Loader : Gap3 setting corrected.
• Dos disk browser : More disks layouts.
• libhxcfe : New track support : AED6200P.
• XML format definitions : Mictrotan 65 TANDOS.
• Flux Stream Analyzer : Possible segmentation fault corrected.
• Flux Stream Analyzer : Input filtering reduced.
• Kryoflux Stream Loader (*XX.X.raw) / analyser : NFA over index support added.
• Track editor : Add & Remove track functions added.
• Track editor : RPM & Bitrate change functions added.
• Track editor : Insertion function added.
• Track editor : Negative offset support.
• Disk viewer : Image CRC32, library version and file name displayed.
• Disk viewer : Track(s) type displayed.
• Disk viewer : Cells density displayed.
• Progess bar added for the loaders/writers.
• SD/USB Emulator setting window : Advanced pinout settings added.
• Code sources fixes/changes for GCC, Clang and VS2015 x86 & x64 compilation support.
• And many more fixes and improvements..

Download:

• HxC Floppy Emulator Software v2.1.4.0 (1957)

source: hxc2001.free.fr lotharek.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 v1.5.0 + Manual (976)

source: csdb.dk

Batch of repairs in one week (report):

• 1 x Amiga 500 (Green screen of death – Replaced 4 x DRAM)
• 1 x Amiga 500+ (Leaked battery acid – Cleaning / Replaced GARY socket)
• 1 x Amiga 600 (Distorted Clipped Saturated audio – Replaced LF347 / Total Recap / Cleaning)
• 2 x Amiga 600 (Total Recap / Cleaning)
• 2 x Amiga 1200 (Total Recap / Cleaning)
• 1 x Texas Instruments PHA-2037 (Missing Pb Component Video Signal – Replaced LM318)

The problem is quite simple to find. You have to make some measurements on the LF347 (Op AMP) with the computer running and without sound.

You have to measuring pin 1 and pin 7 and should have a voltage of about 2.5V if the voltage as in my case is of 11.30v and 11.37v. Something is not working.

After replacing the LF347 with a LM324 or better a TL084 the right voltages are back and the sound works again.

Gallery of the repair:

*UPDATE*

After a couple of days, i have realized that the Amiga 600 still had some problems with the sound, although subtle but annoying and after a few measurements i have concluded that the LM324 is not fully compatible and cannot replace the LF324 (at least on the Amiga 600/1200).

After removing the LM324 and replaced with a TL084 everything has started to work much better than before.

I have done an accurate cleaning of the leaked battery acid on the mainboard.

I have also replaced the GARY socket destroyed by battery acid and rebuild a pcb track with a wire.

Gallery of the repair: