Longhorn Engineer

Same here. Still no product. They are coming don't you worry. It took a long time to source a good number of those FMS6410 chips.

And thats how my mods look.

Not me. My ebay ID is rekarp2.

Little update. I just got finished with my exams. Filling orders again. I got some FMS6410's. I have enough to cover all orders I have but to make sure I don't run out I set the paypal cart to "sold out" on my website. When I figure out how to get around the FMS6400 issue I will open it back up.

Mod will be exactly the same. So, when you send my replacement board, will it be a different design? Will I need to do anything different to my 7800 besides what I've already done? Thanks for the info. No it will install exactly the same as the old 7800 and 2600 mods. Only difference will that the 7800 will be slightly easier to build.

Ok after talking with Fairchild who are the manufacturers of the FMS6400 the replacement is the FMS6406 which is currently still in full production. Current boards can work with it as long as pin 2 is lifted/broken off from the chip. I am redesigning the 2600 and 7800 mod schematics and PCBs to reflect the changes. One change is I am moving the layout around a bit to make them easy to put together and the 7800 mod will get a larger package chip for the chroma switch.

Well back to my original question, do you have a stash of 6400s? I'd like to order a bunch of bare pcbs but only if you have 6400s to go with them, how many can you put aside for me? I only have enough to fill my current orders. I only have 20 or so 2600 and 25 or so 7800 PCBs. So a redesign using a different chip is completely doable. And yes horseboy the FMS6400 is the only one that is obsolete completely now.

http://www.onlinecomponents.com/buy/FAIRCHILD/FMS6410CS/?ref=fc For a stand by. Make sure pin 2 (the NC) is lifted. I don't know what will happen if thats connected to the +5V that is on that pin on the board. Looks like I need to change the design due to obsolete parts.

Yah I just got an email from mouser about it. The FMS6410 is a suitable substitute but I won't update the parts list till I know for sure.

No it seems that the same console with the same mod will display a perfect signal on one TV and on another only a B/W signal. This happens on PAL areas. Seems to happen only on TVs that are both PAL and NTSC compatible. PAL only TVs seem to not have this issue.

The PAL stuff is tricky. Sometimes it works great and other times you only get a B/W image. Seems to depend on the display.

Thanks! Orders are still shipping! I know some people have been waiting but they are shipping!

Maybe this will be useful. http://spatula-city.org/~im14u2c/intv/tech/images/schematic.png Pin 9 on schematic is GND. Is it ground on the USB adapter? I wouldn't imagine that they changed the pinout drastically.

I would be willing to help out a bit Al if it was during the summer or during the winter break.

Sorry Al. I will be at ACL

PM sent: That B&W issue has only happened twice now. Seems that little tiny chip doesn't like boards being flexed during shipping. I thought I fixed it by shipping the mods in the stiffer packaging but that seems to not have worked. Reflowing the chip will fix it. If you can't manage to do it Deteacher then I will send a replacement for a swap. Parker

I think for the PAL the Chroma line needs adjusting. edit// you are picking the chroma directly from the TIA chip correct?

Sorry, I had 1 week to do this lab so I have been stuck on campus for most of the week. I had 1 week to write a simulator for the LC-3 computer. I finished a day early. Getting to emails now. Parker

Well if you take the delay away from the buffer and transistor (~20-30ns). Should improve?

Chroma is received as an Analog signal from the TIA chip so it would not "pass through" the buffer chip. Parker Gotcha. I tend not to think of Luma as digital, though of course here it is since it's just two level. I was scratching my head over that. I thought maybe there was something going on along the lines of CMOS magic, though I didn't see it. Now I see it's just a two level signal. I guess then the question would be, why not use analog amps on both channels (luma, chroma) to maintain the phase relationship? Luma has no real need for a digital buffer. You're just looking to drive a low impedance line, so a pair of low gain amps (a max gain of 2 should make up for any losses) should do the trick without causing timing problems. A reasonably high frequency dual op amp would probably do it. You'd just want to make sure the slew rate is up to par, probably about 250V/uS or better. Anything that can give that good a slew rate will have plenty of bandwidth for old fashioned NTSC or PAL video. Alternatively, a 4016 or 4066 could be used to delay the analog signal if you don't mind adding another component alongside the 4050. Anyway, I'm not trying to tell you how to do it, just suggesting options. There are a number of things to manage in any design, I'm just looking at your phase relationship problem here. Good idea. I will consider it when I am finishing up the 5200 design. Parker

Seconded, the LE 7800 mod I picked up is by far the best out of the many DIY and others that I've used. Thanks Remo

you can try adding some 1k resisters in series then joining the two signals.

Chroma is received as an Analog signal from the TIA chip so it would not "pass through" the buffer chip. Parker

Not when you solder really small painful things