DC2N5-LC : a 'low-cost' powerful Commodore Datassette emulator ...and much more!

Code name : 'DC2N5-LC':

It's the last version (the fifth) of a standalone device designed by Luigi Di Fraia whose purpose is to make digital backups of Commodore tapes. It can also be used as a replacement for the Commodore Datassette 'CN2' allowing you to playback tape image files.The suffix 'LC' stands for 'low-cost' but don't get fool by it because it has nothing to envy to the other commercial devices.It features a connector for the datassette port , a slot for a microSD card, where tape image files can be stored, and a cardedge connector, where a Datassette can be connected, to allow tape content imaging.

As said, it can playback .TAP files (V0, V1 and V2 supported) but what makes this device so special is the .IDX file support that allows you to playback multiload/multiside games & programs (a counter and counter reset buttom have been implemented as well).For a complete overview of its features you can visit the site of the developer :

DC2N version 5 Low Cost

This is really a must for every Commodore nostalgic so, please, support the amazing work made by Luigi Di Fraia and grab a unit! (as I happily did...)

Time Soldiers repair log and 'ALPHA-INPUT84/87' reproduction

Bought on eBay from the States a Time Soldiers PCB which arrived to me some days ago (by the way, thanks to 'coolmod' for his mediation and forwarding) :

Auction described the board as “TESTED NOT WORKING-GARBAGE ON SCREEN-MISSING CHIP”

The missing chip was actually one of four program ROMs:

I programmed a blank EPROM and finally powered the board up.All I got was a partially dimmed screen in which I could recognize the power-on TEST which probaby failed since the board kept resetting:

As usually I do, I started my troubleshooting with a visual inspection.Board was in very good shape but flipping it I noticed scratches on solder side, some quite deep :

A couple of traces looked really severed under the microscope and my multimeter in continuity test confirmed it :

 

Patching the broken traces fixed board completely :

 

The repair was pretty easy, just a quick fix hence it gave me time to look for something on the board to reproduce.The long custom SIL marked 'ALPHA-INPUT84' was a good candidate :

 

  

This custom IC handles inputs and Time Soldiers, being a rotary joystick game, uses four of them (two for 8-way joysticks of both players and the other two the 12-way rotary joysticks).Later Alpha-Denshi games like Gold Medalist use a part marked 'ALPHA-INPUT87' that externally is identical but with slight internal differences :

 

 

The two parts are not interchangeable but I was able to merge both designs in a single reproduction part: :

 

Testing on PCB was successful on Time Soldiers PCB, all directions of both players worked with 8-way joystick (could not test rotary because I don't have them)

 

Another PCB and custom IC preserved!
 

Fire Shark repair log

Got for repair a Fire Shark PCB, a vertically scrolling shooter arcade video game developed and originally published by Toaplan in 1990 (known in Japan as Same! Same! Same)

I powered up the board for the first time and it booted into game.I could coin up and play, sound was present too but screen was filled by garbage (mostly letters and numbers)

 

I noticed that, when I put my fingers on some pins of the 'BCU-2' custom ASIC, the screen was cleaned up from garbage although background graphics were totally absent.This custom IC is, indeed, the tilemaps generator in QFP160 package :

Looking at pinout of the 'BCU-2' found on Out Zone schematics (which runs on similar hardware) I figured out the pins I was touching where a bus that exchanges data with the near 6264 RAMs (8k x 8bit devices) 

 

 

 

Probing with a scope the data pins of the RAMs revealed weak signals :

This lead me to think that the 'BCU-2' was really faulty so I decided to replace it with a spare taken from a donor board.The chip came off quite easily using my hot air station :

 

The spare was soldered in :

Area was cleaned by flux residuals and chip was inspected with a microscope for possible bridges.All was good and ready for the test.I powered up the board again and graphics were fully restored :

I played some games with no futher issue so I could declare the board 100% working.Another sucessful repair accomplished.