cbmeeks

Yeah, that's a good point. I actually prefer the composite mod to my CV anyway. Although I added the F18a to my TI. I assume this is probably because you have to de-solder the VDP on the CV and that shouldn't be done unless you know what you're doing.

This is awesome news but how are games like Gradius and Donkey Kong licensed? Is it because CV had the rights at one time? I speak from personal experience with dealing with Nintendo and IP. With a single email they seized my server and my own personal content.

Pish posh. Lol

Ah. Yeah...that's not cool. That's a little scary because unless you frequent this forum, you may not know the good from the bad.

I'm confused. Is he making bootlegs and selling or selling his copies of SGM games he bought? I.e., did he buy a legit copy and then sell it?

I'm curious...how was 12 chosen? I'm sure Coleco did extensive market research. Lol

That's good to hear. I read most of the other thread but I can't remember what all you had planned. Would you mind a recap of the planned features? Thanks!

What's the latest on the new CV board replacements? I believe there were two of them right? The official threads seem to have tapered off or stopped altogether. Thanks.

Has there been any games designed that require the SGM and the F18a? Seems like that would be a powerful combination.

Great news!! I'm glad she is doing well.

I actually may do that. I hate having dead, vintage computers. Plus, I want to improve my diagnostic skills. My problem is that I have so many projects...lol

UPDATE The motherboard swap appears to be working. The computer has been running Parsec for 2.5 hours with no issues. Fully assembled. I ended up using the RF shielding and putting a dab of thermal grease on the small heat-sink. Overall, I'm happy that I have a F18a equipped TI. Just too bad that I now have a "parts" TI that doesn't work. Oh well...maybe I will buy a couple more to make up for it. ;-D Thanks for all the help everyone.

Looking forward to this!!!

OK, I looked at the slide-on heat-sinks mentioned by @Stuart. Those look great but I think the issue is that they require a clamp that goes under the IC so that it snaps on. I'm not sure that would work on the socketed clock chip. Unless there is another way it can clip on? Is there a thermal glue or epoxy that could transmit the heat and not melt? Thanks.

I like the idea of those slip-on heat sinks. I may go that route. One thing I noticed is that the original motherboard that did NOT have a heat-sink on the clock chip is newer than the motherboard that did have a heat-sink on the clock chip. Same goes for the chip itself. It seems newer too. I wonder if the newer revision runs a little cooler so TI thought a heat-sink wasn't needed? I went out and bought some snips that can cut metal. I was cutting through that RF shield like a hot knife through butter. LOL So I might just go ahead and put it back together and use the RF shield until I can order some of those heat-sinks. I actually don't want to use that shield. Seems way too easy to accidentally short something out. I'm sure the engineers at TI knew what they were doing but the whole TI seems like an odd design sometimes. And yes, I'm familiar with those weird, white voltage rails. I've never seen that before in any other computer. Not like that anyway.

UPDATE: I took the motherboard from my donor TI and plugged it into the power supply of the dead TI. And it worked. So I believe the PSU from the original TI is good. I swapped out one of the socketed chips from the good motherboard into the bad one and it didn't work. I didn't do the other three because it was proving to be difficult to pry them out and I didn't want to take a chance on damaging the donor TI *working* motherboard. I started thinking that whatever has caused the original TI to die could possibly cause it to happen again if I start swapping parts out. So I think the original TI motherboard is going to become my donor TI motherboard and I'm just going to swap the boards out. HOWEVER. There is something different about this board. The clock chip is socketed (the original is not) and the clock chip on this one had a smaller heat-sink block for it. The chips look to be the same model number. I won't be able to use the RF shielding on my F18a mod board because I don't have a cutting tool that can cut the metal shielding. ** EDIT ** I've been running this for 5 minutes and the clock chip is really hot. I don't think I want to run it without cooling. Any recommendations on how to attach a heat-sink when I can't use the RF shielding?

That sounds like a reasonable idea on the sound. Previously, when I turned it on I would get a really loud beep before the normal "welcome to TI" beep. That makes sense. The sound IC comes up in a random state and the CPU reads from ROM the silence commands. I checked pin 1 and it was -5v. I'm not sure how to test the reset. My scope shows it at low when the power is off and when I turn it on, it seems to stay low for a second and then go high. I don't know if it is actually holding low or just immediately jumping to high on power up. I checked the IAQ and it looked like a square wave of about 300KHz (IIRC) but it appeared to jump around a bit. I assume it was executing commands. Any other ideas on testing the CPU better? I actually have a spare CPU I bought on eBay. But I have to admit...I'm not sure I want to de-solder the old one. I'm pretty good at soldering but I always have a dickens of a time de-soldering. Not sure why.

I might do that. I'm sort of a hoarder with my vintage collection so I always cringe when I have to "steal from Peter to pay Paul". But I may not have a choice on this one. Shoot. I might just buy another couple TI's. LOL But, the engineer in me wants to solve this! UPDATE: Now this is weird. Remember the continuous tone I mentioned? Well, I turn on the console and get a high pitch tone. Turn it off and back on and then I get a low pitch tone. Back and on again and it's high pitch. I did it like 10 times and each time it toggled between high and low tone. I could see a random tone. But a continuous toggle of high/low?

Update 2: I swapped in another TMS9918ANL and got the same thing. I can't prove the other 9918 is good or not and I bought it from eBay a long time ago. Black screen, continuous tone. :-(

Update: I put the TMS9918 back in. I connected it via RF and get a black screen with a very loud, continuous tone from the speakers. I have other TI's but I really would hate to gut one of them if I didn't have to. One of my TI's could be my "parts TI" but I'd like to find the real fault if I could and see if I can get a replacement chip. Any ideas now? Thanks.

Nope. Nothing connected. I've downloaded the datasheet to the TIM9904ANL that I have. Well, the datasheet I found was for the TIM9904A but I guess that should be good enough? There was only the one heat sink block installed. 1) Do I need the keyboard attached to the motherboard to get the normal screen? I'd rather not take it back out if I don't have to. I currently have the main board and the PSU on my table. ** UPDATE ** I got the following frequencies from the clock chip. O1 (12), O2 (11), O3 ( 8 ), O4 (9) = 3 MHz. However, it was an "inverted" 3 MHz meaning the duty cycle looked more like 20% high, 80% low. I forgot to record the exact duty cycle but I can. XTAL2 (19) = 12 MHz but closer to a sine wave than a square wave. But I think this is normal because my scope is only 100 MHz. XTAL1 (18) = Unreadable. Just a wavy mess with no signal to lock on. OSCIN (17) = Flat 5v. Couldn't detect a frequency. OSCOUT (16) = 12 MHz. (same as above) O2 TTL (15) = 3 MHz duty cycle appears to be more high than low. Pretty much reversed from the O1-O4. O1 TTL (14) = 3 MHz same as O2 TTL. VDD (13) = 12v VCC (20) = 5v Not sure what the other pins are for. Also, I should note the chip feels warm. Not hot but certainly warmer than the others. But I suspect that's because of the many clocks and 12v? Thanks again

I reseated the socketed chips. Still doesn't work. Yes, the metal shielding had a block screwed on. But I'm not using the metal shielding at the moment. Which chip is the clock chip? I have an o'scope but I don't know what to check. Thanks

So, I installed the F18a in my TI-994/a about a week ago. I've had the computer disassembled on my desk and have tested it out over and over. All was great. Today, I installed the motherboards back in the case and permanently mounted the VGA connector. Everything was working great. So I thought I would let it "burn in" for a while. I left it running for about 1-2 hours and came back and the screen was black. Now, when I turn on the computer all I get is the power LED and the splash screen to the F18a. The audio is a loud continuous tone and nothing else works. I disconnected the speech synth too. The area above the PSU was pretty warm but not too hot to touch. I'm going to let it cool down for a while and try again. Have I lost my precious TI? Oh, one other thing. I didn't put the RF shielding back on because I don't have a way to cut the metal. But I've used it assembled for a few hours but only a few minutes at a time. Any help is appreciated. Thanks.

This sounds funny to me. But play Star Trek on the TI with the speech synthesizer. When the game starts, it says "Welcome aboard. Captain..." LOL. Seriously, it sounds like the game is saying you're not a real captain. Who does he think he is?

Thanks for the information. I just may perform that upgrade. I am looking to buy the new 99 Flash ROM too. So between the 32K RAM, the F18a (that I own) and the 99 Flash ROM, my plans are to play some awesome games. Unfortunately, even though the TI994/a was my first computer, I don't know much about it (I was 9 at the time). For example, I still don't get the difference between ROM and GROM.