Radio Shack TRS-80 Model 1 Repair.

This is the second time that this computer was repaired within 2 years.

Defect:

• Video Sync issues (Horizontal Driver) and then … garbage on the screen.

Replaced parts:

• Replaced 1 x CD4069 HEX Inverter (Z6)
• Replaced 1 x MM2102 RAM (Z62)

The Prism QL 14 is a Color Monitor for Sinclair QL. The monitor has an Scart input (RGB) but unfortunately that is not fully compatible with other devices that use the Scart output as video.

Some photos of the monitor cleaning:

I thank my friend Giacomo Vernoni for having given me this console that i was looking for a long times. This the link of the Giacomo blog where you can find a complete review of this console with some beautiful photos.

Gallery:

12►

Following Commodore’s acquistion of MOS technologies (famous for producing the later 6502 chip for the PET), the Pong-like TV Game consoles 2000K and 3000H made their appearance.

The 3000H console features two paddles (sliders), one internal and one connected by wire (with 2 additional optional sliders); 9VDC or battery power (6 AA batteries required, yes it can run on batteries!).  It generates its own sound with the built-in speaker and can play 4 games: Tennis, Target (with an optional light gun), Football and Squash.  There is also a gage for difficulty level (handicap), and another for the number of players and other settings.

The cool thing is that the core chip, the MOS 7601 (the last of MOS’s Pong-chip line) read game instructions from a special ROM which appears to be internal to the chip, making it stand out from the other Pong-clones that had the game hard-coded into the system’s logic

However, because graphics and sound are also generated directly by the 7601 and are hardwired into the chip’s logic, it meantthat special variants had to be created if a special display was required for an arbitrary application. Thus, the 7601 in the TV Game series, while being programmable in a crude sense, is hardwired to generate the graphics for the TV Game series’ internal games only and cannot be used into drawing other kinds of shapes.

Games available were the following four:

• Game mira (playable with an optional optical gun )
• Tennis
• Football
• Squash

source: computinghistory.org.uk

Repair Commodore Amiga 3000 Motherboard with Battery leakage

There was once a motherboard of an Amiga 3000/25 devastated of the Battery acid where missings all the socketed components and others are unsoldered and recovered for other things.

The situation was not exactly the best one, in other words … was going into the box of spare parts.

I made the impossible, i have cleaned, scraped and rebuilt many tracks of the pcb corroded by the battery acid and i must say that with lot of patience i have repaired the motherboard giving a new life to this Amiga 3000/25 that he had no many chance to come back to work

Ikari has released a new firmware for the SD2Snes Flash Cartridge (Super Nintendo/Famicom). The upgrade instructions can be found here.

Full Changelog:

• In-game button combinations are in effect. See the table below for the key mapping. Note that some games show glitches with the in-game functions in place. I added an additional feature to temporarily disable them in case of game glitches (e.g. Secret of Mana hangs at the Squaresoft logo, displaying only garbage). I’m not entirely happy with the button choice but it will do for now. ;)
• LED blink codes for file system errors – e.g. in case the SRM file cannot be saved this will tell you that something’s gone wrong. The blink codes are yet to be listed.
• Also the sd2snes will retry saving until it works so you have the chance to swap out the SD Card. In that case the directory structure must be present where the sd2snes expects to save the file.
• “Screen saver” – in the menu, the screen is darkened after some idle time to reduce wear on CRT and plasma screens.
• Memory sharing between SNES and the sd2snes CPU is greatly simplified (The FSM is reduced to only 5 states instead of 18) and timing is more relaxed. This should help with stability on a wider range of consoles.
• On-the-fly file browsing. Also shows a little “loading…” window when loading directories/files.
• Windows are now blue so they stick out better in front of yellow directory listings.
• Cx4 data ROM is now embedded in the FPGA configuration – no more need for the external file cx4.bin.
• Initial Satellaview clock is back to 18:00:00 from 18:05:30.
• SD cards can be hotswapped. Currently there is no automatic refresh of the file list so tapping reset on the SNES or changing the directory is necessary to get the new contents.
• The status line is moved upward a few pixels so hopefully it doesn’t get eaten by overscan.
• Navigation: When scrolling page-wise with the right D-pad arrow, the end of the file list is now aligned to the bottom of the screen.
• Navigation: The shoulder buttons can be used to jump to the beginning/end of a directory listing.
• Bugfix: some compatibility issues with a number of games. (Super Play Action Football (S-RTC interference), GP1 Part II (WRAM initialization), Human Grand Prix (mapper detection bug))
• Bugfix: properly initialize FPGA state machine (on some consoles the menu failed to start at all)
• v0.1.7 final will contain menu items for various configuration settings and a cheat interface.

In-game button mappings:

• L+R+Select+Start = Reset game
• L+R+Select+X = Reset to sd2snes menu
• L+R+Start+B = Disable cheats
• L+R+Start+A = Enable cheats
• L+R+Start+Y = Kill in-game routines (in case they interfere with game operation).
• L+R+Start+X = Temporarily kill in-game routines (~10 seconds – if you need to get past a glitch but don’t want to lose in-game buttons)

Download: SD2Snes Firmware v0.1.7 Beta/Preview (1278)

source: sd2snes.de

Apple IIe Power Supply Repair.

Defect:

• Dead with clicking noise in background (This power supply works even without load)

Replaced parts:

• Replaced 1 x 200uF 10V Electrolytic Capacitor.

Removed as a precaution the RIFA filter capacitor.

Gallery:

Epson PX-4+ Easy Repair

Defect:

• Dead.

Replaced parts:

• Replaced 1 x Fuse 3A

Removed the internal Backup Battery (RB 301) 4.8v 90mA.

I must thank my friends which have contributed to the growth of my Repair Laboratory with donations of spare parts.

Donated items:

• 2 x Sega Dreamcast
• 1 x Sinclair 128+
• 2 x Amiga 500 Memory Expansion
• 1 x Amiga Powersupply
• 1 x Philips Multi Voltage Power supply
• 1 x Commodore CBM/PET Power supply (complete and working)
• 1 x 8088 Motherboard (Clone)
• 1 x Floppy Drive Controller (ISA Card)
• 1 x MDA/Parallel Controller (ISA Card)
• 1 x PC Clone (8088) Power supply
• 6 x Unknown Adapter/Interface
• 1 x Atari 7800 Motherboard
• 1 x Sinclair ZX Spectrum 48k Motherboard
• 1 x Pong Clone Motherboard
• 1 x Amstrad CPC 464 Motherboard
• 1 x Commodore 6499
• 1 x Power Supply C64/VIC20 (Clone)

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

Titles:

• Bozo’s Night Out +7HDG
• Vallation +6HD
• Foren Huren +Docs [pal/ntsc]
• Mag Max +8DGH +Pic
• Burnin’ Pen ’64
• Zappy Bird +2
• Ugh! +5DGM
• Eelona Preview +2
• Beyond the Night Run +3H
• Spike’s Peak 101% +7DGM
• I Can Remember +D
• Batman – The Caped Crusader USA + [ntsc/pal]
• Space Action 2 Preview
• Game Preview #1
• Game Preview #2
• Mad Ninja Preview
• Slug +30D +Fix
• King’s Valley Preview
• Burnin’ Pen ’64 [bugfix]
• Total Eclipse II -JEWEL-
• Mission Omega +1D

Download: All Games in One Archive (2897)

Commodore VIC-20 Repair

Defect:

• Black screen … then black and white image.

Replaced parts:

• Replaced 1 x 901486 KERNEL ROM (U12)
• To fix the problem of the image in black and white i have adjusted the “RED” trimmer (C48)

Commodore 16 Power Supply Repair

Defect:

• Output voltage in short circuit.

Replaced parts:

• Replaced 1 x 4700uf / 16v Electrolytic capacitor.
• Replaced 1 x 800mA Bridge rectifier.

Atari 2600 Repair

Defect:

• The second joystick port doesn’t works properly.

Replaced parts:

• Replaced 1 x 6532 RAM-I/O-Timer (RIOT)

This is another adapter (here the previous one) to replace the MPS 6550 RAM. This adapter replace a single MPS 6550 RAM chip in a Commodore PET 2001 with a standard 2114 RAM chip.

source: dasarodesigns.com

Commodore CBM 4032 (40 Columns) Repair

Defect:

• “Device not present” error when using the IEEE 488 port (Example Floppy Drive)
• Sometimes the computer show the prompt of the TIM monitor (Machine Language Monitor program)

Replaced parts:

• Replaced 1 x IC 6522 VIA (UB15)
• Replaced 1 x IC 6520 PIA (UB16)

These are my two Commodore PET 2001-8C (Chiclet). They are two different models, below i will list the differences.

On the left:

• Different front Label.
• PET Motherboard ASSY 320132
• Different Copyright Label on motherboard (1978)
• Uses the 2114 ram ic for the Main memory and for the Video ram.
• CRT tube with green phosphor.
• The transformer, the big electrolytic capacitor and the power connector are different.
• Datassette Motherboard ASSY 320275-B (1978)

On the right:

• Different front Label.
• Motherboard ASSY 320008
• Different Copyright Label on motherboard (1977)
• Uses the MOS 6550 ram ic for the Main memory and for the Video ram.
• CRT tube with white phosphor.
• The transformer, the big electrolytic capacitor and the power connector are different.
• Datassette Motherboard ASSY 320109.E (1977)