Recent content by robf2

Yes I tried the various rom search tools. I couldn't get WinRomIdent to run on my Win10 machine or my WinXP virtual machine. The dos version couldn't identify the ROM (or several from the standard MAME group). It was the same for the web based checker. -Rob

Well still no joy on getting the free rom working, but I don't think it is the chip compatibility anymore. I tried all three versions of the Rom images. None of them worked. My board is marked as 6/25, but strangely enough when I compared my standard D2 image against all MAME images, it is...

Well hot damn. I at least got the stock image to work on the 27c256. It turns out I had a hand edit error in the binary code. I had accidentally added an extra 0x00 byte ahead of one of the 8k duplicate blocks. And of course as luck would have it, Tron wanted to read from that part of the...

Ok so an update. I tried the 32k duplicate image and had about the same garbage screen result originally. I then tried the stock D2 image also duplicated to fill the 32k space. This time the behavior was a bit different. Instead of just garbage on the screen, it cycles through the first...

Ok, got it. That matches what I was getting at. Thanks for the info. Of course the schematic doesn't say what they did with pins relating to A13/A14/A15 lines (which are N.C./PGM#/VPP for the D2764 respectively). The other, more robust option would be wire these pins to gnd. However in the...

Ok, I understand the size difference, but are they not pin compatible at least for the lower address pins? Why is it necessary to fill the repeating 8k image for addresses that the CPU shouldn't try to address? It is just because the normally N/C pins are floating and could non deterministic...

27c256 suitable replacement for D2764 Eprom? Tron freeplay Hi all, I am getting my Tron ready for the NWPAS by adding the freeplay mod. I had thought I could use a 27c256 as a substitute for the standard D2764 ROM. However after trying both the freeplay rom image and the image read off of...

Yep, that is what I was leaning towards and was hoping to hear. I replaced it and it powered up fine. The board is noted as 1990 so I guess potentially the caps could be 25 years old. It seems wrong to have to recap an unused board :) -Rob

Hi all, I recently purchased what I believe to be a new old stock chassis. I installed it in place of another working k7xxx chassis with no changes to the power supply or CRT. To my dismay, the instant I applied power I was greeted with smoke from the flyback area. After careful inspection...

I also like this one for gradient testing -Rob

That was me. This is from the eizo calibration tool. I find it really handy for convergence testing. -Rob

The best way I can describe it is that it seems that the slot mask isn't consistent across the screen. It is like the columns of slots are not evenly spaced. This is sort of what it looks like to me when I set to one solid color; | | | | | | ||||||||||||||||||||||| | | | | | | |...

The thing is, it isn't in the corners, it is perfectly consistent from top to bottom and it gets progressively better as you go from the outside to the center. I will try to take some better pictures. Ok, now you are purposefully trying to confuse me :D -Rob

Creative degaussing did not change the behavior, although it did clear up the color blotch in the one corner. I spent some time with convergence (which wasn't far off to begin with) and the main issue still exists. Any other ideas? Is this a potential for rejuvenation? -Rob

Original Tube: Zenith G-AC3ADG25X Horz: 1.7 ohm Vert: 10.4 ohm Donor Tube: Sharp (Sanyo?) A63AHC26X Horz: 1.6 ohm Vert: 8.0 ohm Ok will give creative degausing a try. -Rob