Happy New Year

 General  Comments Off on Happy New Year
Jan 012018
 

Happy new year everyone to everyone that visits this place and a big thanks to all that have either contributed or made a donation.
Hope you all have a great 2018

 Posted by at 12:48 pm

Pooyan Diagnostic ROM

 General  Comments Off on Pooyan Diagnostic ROM
Dec 092017
 

This is an initial test release.

Reported to work nicely on real hardware.

http://www.ukvac.com/forum/pooyan-diagnostics_topic360411.html

This EPROM installs on the CPU board @ A4. This does not replace the original software but is only used as a means of testing the main-board, sound and video hardware. Detects STERN, KONAMI and POOTAN versions of the software.

Diagnostic mode is accessible by holding down player 2 start whilst powering on the game or enabling demo sounds via dip 8 of dsw2.

Version: $55BF

See current version for download

Some diagnostic ROMs added

 General  Comments Off on Some diagnostic ROMs added
Dec 072017
 

Thanks to the courtesy of ‘philmurr’ we can host all his test ROMs for arcade PCBs.They are specific for :

  • Galaxian
  • Moon Cresta
  • Mr. Do!
  • Phoenix-Pleiads
  • Scramble

ROMs have ben tested on real hardware.You can read more about on UKVAC forums :

  • Mr. Do! :

https://www.ukvac.com/forum/mr-do-test-rom_topic361108.html

 

  • Galaxian, Moon Cresta and Scramble :

https://www.ukvac.com/forum/test-roms-galaxian-moon-cresta-scramble_topic355745.html

 

  • Phoenix and Pleiads :

https://www.ukvac.com/forum/phoenix-and-pleiads-test-rom_topic360891.html

Thanks again to him.

 

 Posted by at 8:41 pm

‘For Sale’ Section

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Sep 242017
 

As you may now notice there is a new tab on the menu bar called ‘For Sale’.
At present this is just a simple gallery showing items that we may be selling at any particular time.

If your interested in any items then please contact the seller directly via the contact form

 Posted by at 6:03 pm

Commodore 1084S-P1 repair log (part 3)

 General, Monitor Repair Log  2 Responses »
Sep 112017
 

During my Hypersport’s repair I discovered a problem with the display of my Commodore 1084S monitor. Notice blue missing for “3 LONG HORSE” and “7 POLE VAULT”.

This will be the third time I’ve performed a repair on this old monitor which I’ve had since the early 90s for my Amiga 500 and 2000. At first I would suspect the AV7000 Supergun as the culprit. But subsequent tests would prove otherwise.

There’s definitely a better picture with composite or svideo from my c64 and Atari 8 bits but there seems to be a problem showing blue on the RGB input even though some blue is there ( turquoise , cyan.. etc ) in other images. Adjusting the blue gun and turning up the contrast just makes the backgrounds in Puzznic more blue. Where blue is supposed to be on the screen, it seems to not be present as though the signal were being cancelled out.  With no RGB signal to the monitor at all, it defaults to a blue screen instead of a white one.
Apologies for the sync bands.
I suspected the neck board transistors, so I pull out the one responsible for blue and tests with my multimeter show it’s fine. I even swap the transistors around to see if the problem would move to the other gun….  but it doesn’t.
I found this really good post on eab [ English Amiga Board ] by Loedown
IC502 TDA 3505 pins 12, 13, 14 are RGB in from Euro Connector /SCART, check voltages there to begin with when inputting a perfectly white screen. Then follow the voltages through to transistors TS604 – 606.
The schematic shows the analogue inputs go directly from the RGB connector to the Philips TDA3505 IC via some 100nf caps. Pins 12,13 & 14 are the input RGB signals. I measured 4.3v for red and green but 9.1v for blue. That seems a little too high for blue and the schematic indicates 4v for those signals.
I order some TDA3505s on eBay from atarifreakz and my package arrives a few weeks later.
 
Not wasting any time. I replace the chip and the picture is now perfect!
The Taito logo and blue shadow around the Puzznic logo is now visible. Notice the bricks and backgrounds are also showing up right compared with the previous screenshot.
 
I wonder if there will be a part 4 🙂
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