jdgabbard

I get that. What I'm saying is that I don't understand how the crystal could be out of spec, yet still offer the right pulse for the V-sync and H-sync. Of course, I could also not be lazy and actually look at the schematic and figure out the theory of operation. Best guess is that it's not out of spec enough to cause disturbance in the picture clarity...

Yeah, I've read through that page. I think I'm going to replace it. What I don't understand is that the CGA card doesn't have its own oscillator. So even the H-sync and V-sync would run off that signal, unless I'm missing something. And there is no problem with those, I get a sharp picture. Just no color.

That's kind of where I stand. It's one thing to emulate hardware, you're replacing older unavailable components or making transfer between modern PCs more efficient. It's another thing to emulate machines in a virtual environment. Not that it doesn't have a place. Take NES emulation, or any other console for that matter. But, in my mind it's for hipsters. If you get off on writing the code and accomplishing the goal, so be it. But I'd rather play in real hardware.

I don't have it in front of me, but I believe it's the newer board for the IBM card. It is brown...not that this helps with the ID number. However the other card is a Color/Mono Paradise CGA card. It displays shades for colors, but not color. And has a 16mhz onboard XO oscillator. I'm guessing that it is for the Mono. From what I can see when adjusting the Cap and your description above conceding the crystal frequency, it is likely a faulty variable cap. I'm going to have to find a replacement. The closest I can find in the proper footprint is overseas. I may have to breakdown and order it.

That would definitely make sense. I'll have to source a part, the footprint is too large for the adjustable caps I have on hand. The cap appears as it does partial work, since I do see the horizontal sync change just a tad bit (wavy lines to the right of characters).

So I have been working on getting my IBM 5160 restored. Most things have been cleaned or repaired at this point. I had to remove a few capacitors that were shorted internally, sand the badly pitted case, repaint, etc. The biggest problem I had run into was how to get an image on the screen. It had a Paradise Hi-Res card in it, which had a cga 9-pin connector. But I do not have a CGA monitor. Which created a problem. So I bought a later IBM full size CGA card with Composite out. This worked ok, but it did not display any color. I tried fooling with the trimmer pot on the motherboard. Unfortunately, this only served to adjust the horizontal sync. Colors display horribly, mixing both fore and background colors and was completely unusable. After doing more research I discovered that most CGA cards have a header on the board for Composite out. The IBM card does, I looked, and the Paradise card does as well. The paradise card is obviously a newer card, being half-size and offers both color and mono mode by means of a switch. And also an addressable LPT port. Ensuring that the card was installed correctly I sat down at my bench and fabbed a bracket with a RCA socket, and a wired connector for the composite header. Connected everything up, and fired up the machine. After a few seconds the video initialized, and I began to see the ram check. But this is where my luck stopped. After making sure that the board and the card are configured correctly with the main board dip switches and the jumpers on the card I can not get this card to display colors. It displays them in greyscale. Which is better than B&W, but not what I want. I have a RCA broadcast monitor that I can't wait to get colors on, but I have also tested against another CRT and a modern LCD. All with the same results. I know that the motherboard crystal is probably slightly out of spec. But the system runs fine, and if it were really bad I would just get garbage on the screen with the IBM card which uses the system clock for timing. The Paradise card has its own 16mhz XO oscillator, so color timing shouldn't be an issue. From what I understand these card do display color on the composite out. So I'm at a loss. I have used mode.com to configure the various video settings between BW40 BW80 CO40 and CO80. I can obviously tell the difference in display modes, but still no color. Any idea?

When the original came out we at the time didn't have a PC at the house. We had in the past, a 286 machine if I remember correctly. However, I was pretty young at the time, 4-5th grade. I would go down to my father's office and play on his 486. He was real good about getting me started in PC gaming. One day he showed me the game, and it really locked in my desire to completely switch over from consoles. Although,I had always played games on computers, I was at this time mostly playing Genesis games. Shortly afterwards we bought a pentium platform. Which continued to be upgraded wit the newest and most expensive hardware available until I got out of High school in 2001.

Pentium IIs are great for setting up a DOS gaming station in my opinion, for games 1990-1999 that is. Anything older, you'll likely want a (3/4)86 with the turbo feature so you can slow it down. But in my opinion, the 90s were the golden era of PC gaming. Don't get me wrong, there are thousands of fantastic computer games that do not fall into this genre. However, this period is when PC gaming REALLY took off. To give you an idea of how modern those old systems were, I'm posting this from my own 90s gaming rig. See the attachment and specs below. PII @ 350mhz 384MB RAM Voodoo2 2000 PCI 3dFX card 80GB IDE HDD 100m/b Ethernet card (Attached to Netgear Wireless adapter) SB16 PCI Card CD/DVD-ROM 1x 3.5" Floppy Windows 98 (Says ME, has the Unofficial SP3.4 upgrade) This machine can not only play basically every DOS game from 90-99, but practically every Windows game from the 9x era. All while still being able to surf the net, download updates as they are made available and install any utilities that are needed to keep it running (an an example the WinME Defrag, which runs 10x faster, and does a better job). P.S. I appologize for the size of the attachment. Due to the resolution of this PC it is almost unreadable when resized. screenshot.bmp

Well, if the code is for a 20v8 it likely would compile and work on a 22v8 with minor changes to the code. However, you would likely soon fine it didn't work (depending on pins used...I haven't looked at the code in a while and I'm on my phone). It depends on the features used. Alternatively, you could buy this and have a few to experiment with... https://www.ebay.com/ulk/itm/230505069621

The JEDEC created SHOULD be compatible. There may be an issue with the routine used by the programmer to write the fuse map. An example is that the TL-866 supports GAL16V8 and 22V10, but doesn't mention any PAL versions that I'm aware of. The PAL family is reprogrammable, however, the chip may have been written to many times. Hard to say.

My recent experience proves that Lattice gals work fine with WinCUPL. My guess, you have something wrong somewhere else on the board. If the code compiles correctly it should burn to a Atmel or Lattice fine. My recent research shows that the JEDEC files produced are pretty much universal within the variants of a particular chip. Here is an example of a Lattice chip that is running a JEDEC that was written and compiled using WinCUPL: http://atariage.com/forums/topic/254989-dual-bcd-to-hex-7-segment-driver/ Now, they do have different programming protocols, so you'd have to program them with the specific chip setting. However, barring that, the only other issue I could say would prevent it from working is it not being correct for your version of the board. If it is for your version, you have a different hardware issue. Faulty capacitors are notorious for causing problems...

Ziggy, I apologize that I'm just seeing this. It's hard to say... I could probably try compiling and test that it works on a similar chip (22v8). But whether that is the code that is supposed to go onto your particular board or not is a whole other story, and I don't have that machine to work with. So it's probably of no use to you.. I've still been messing with GALs. I just posted a link to an instructable I wrote on one last night. But I know nothing of Amigas. One thing to note is that the chip it calls for is different from what your link calls for. However, I'm sure its only a different variation that is pin compatible. So as long as your used the proper chip selection for compiling and burning the JEDEC I would assume it would work. At a glance it looks like the code would work, and that it is simply combinational logic.

I'm not sure if anyone has a use for this on this forum. But I just got done posting an instructable on using a single PLD to drive two 7-segment displays with true hex values (not the crazy characters some display drivers use). The project uses a GAL22V10, with a clock signal, and takes a 8-bit binary number, and outputs to two displays by way of multiplexing with two enable/sink pins to select the display that is intended to write to. Here is the link: http://www.instructables.com/id/Dual-BCD-to-Hex-7-Segment-Driver/

Well, technically the Pocket C.H.I.P I am posting with was bought in 2015, but i just got it a few days ago. So it counts, right? Other than that I snagged a IBM 5160, a Packard Bell 286, a IBM Aptiva 486SX, and a CoCo Model 2. So i guess its been productive.

Well, I will try to answer your questions and provide you with a little more info. And assume you're talking about electrolytic capacitors. 1) it is likely that one or two events occurred. One, that portion of the genesis hadn't powered up yet. Ie, it is something that is controlled by the system and is not just a cap on the power supply. Two, the capacitor simply didn't have enough time and current to fail. I've accidentally switched caps around when I'm prototyping, they usually get warm then the circuit starts acting erratically. 2) They are every important, and have many functions. But regulating voltages is not one of them. Depending on the type of capacitor and it's placement in the circuit it could be for stabilizing the power supply (when parts of a circuit turn on it can cause a sudden drop in voltage), act as a filter to block noise around integrated circuits, a filter to block DC and allow AC to pass, etc. Really, you could spend a long time studying capacitors and still learn more about how to use them. Heck, you can even use them as a analog delay. 3) No the electrolytic capacitor would shortly fail usually resulting in it exploding, leaking the the electrolyte over the circuit board (bad, causes corrosion), and possibly cause a short on the power supply causing the system to stop working. As for caps going bad, it's because electrolytic and tantalum capacitors tend to go bad with ECs leaking electrolyte, and tantalum caps shorting out internally. In either case, depending on the severity of the damage the system may or may not work.

Man, that's cool. I like seeing projects like this. As for what it can be used for, I could go on, but mostly DIY computer systems. Lots of people build 4-8 bit computers out of discrete components. Hell, I even have an ALU that I hand coded on an EPROM. That was fun doing all 4K of calculations by hand...

Another thing, there are some unofficial updates available. Many people suggest downloading and installing them. But now that I'm thinking about it, I always had problems after installing the. And I would have to revert back to a standard install, and simply use the latest official updates which can be found online. That my suggestion.

I'd keep 98SE. I had 2k, along with all the other windows systems. After 98SE the next stable OS in my opinion was XP. You want something that will be stable. And there are drivers for USB mass storage, which makes file transfer easy. On my machine I have a couple of ISA cards as well as PCI, they work fine. Of course I have 384MB of memory. Also, I highly suggest getting a Voodoo card for OpenGL games (read Quake). A standard VGA card will work fine, but the graphics are not as good. Also, 98SE will recognize very large HDDs. I have an 80GB drive in mine, which comes in handy for putting many games from the mid to late 90s on. Many of them, once decompressed, would be in the area of 1GB a piece.

Now, I've never made a cassette cable for a TI-99/4A, but I have made cables for other computers. It appears that for a single cassette you'll need the following connections: Pins 6&7 are the motor control pins, pin 3 is Mic, pin 8 is the audio in (headphone), and pin 9 is a ground. The ground for Mic and headphone would likely be tied together. I'm not sure what pin 4 does. So if it were me, I would wire my cable like this and test Mic -> 3&9 HPs -> 8&9 Motor -> 6&7 But without my TI handy to do some probing, this is a best guess.

Although, I will say that isa is notable slower than pci. But one or two cards isn't going to bog down a system that much.

Not sure how much of that I believe. 16-bit Soundblaster ISA cards were still the most desirable back during that era. If there were negative performance issues I would think that people would have chosen something different.

Ok, I understand, it's an issue with the colors. I guess another alternative may be to check pin 7 on the computer. From what I'm reading, there may be composite video on that pin. I guess once I get done moving this week I can break out my oscilloscope and check it to see. There isn't a jack on the board, and if my memory is correct, there isn't a place on the board. So it's possible that pin 7 is occupied, I suppose.

Seems rather pricy for something that looks to do the same thing as the lower price item mentioned above. (I checked they go for about $20 USD.) It does have a nice enclosure. I can fab an enclosure, I've been working with ABS for quite a while now... is there any specific advantage of this unit over one of the others? Or is this just a unit you have used and recommend?

Yeah, as I mentioned above, it's outside the budget at the moment. I'm moving, and a) I don't want to lug it a move, and b) finances are a little tight until I get settled. So I'm looking for a cheaper alternative. Hey! I didn't see that before. Looks like a .200 spacing. Should be fairly simple to wire up with a DB9 connector and shroud. Or just do something panel mount in an enclosure. I think those were pretty cheap too, like $30 if my memory serves me.

I'm familiar with the different modes:composite, RGB, also many had a B&W mode. The particular board in this PC offers color and B&W, but no composite. As for the converter board, from what I have read, those are made for arcade RGB, which uses a slightly different format. A passive cable and a suitable crt could be possible, but they're hard to determine if they will work while in the wild. Those are the reasons why I'm particularly interested in whether there is a terminal mode for RS-232