Hi y'all -
Back when I was a kid my first computer was an Apple II+ and I had an Echo II speech card for it. Somewhere along the way I picked up a IIe and traded away the II+. Thought I had kept the Echo II but when I dug the IIe out of my parents garage on a recent visit just before the pandemic hit I could not find it so seems not.
Being a bit of a hardware hacker, and I been lurking here a long time so I know there are plenty of y'all who are way more knowledgable than I, I got it in my head I should try and make my own Echo II clone.
There appear to have been several versions of the Echo II card. Some earlier ones used the TI TMS5220NL and later, I assume they were later, used what looks to be a custom echo chip manufactured by TI. That or it's just a rebranded TI Chip.
There appear as well to have been several versions of the TMS based Echo II. One had an additional two sockets on it. I assume for additional ROMS. There were also IIb and Plus versions as well which both used the TMS Chip.
For starters I'd like to clone the Echo II that did not have the additional chip sockets. Problem is I don't currently have an Echo II with the TMS chip that I can use as a pattern. I have some pix off the web and off eBay but I can't tell what the value of all the capacitors, resistors and the pot are. Also there are some traces I just can't make out.
So I was hoping someone here might have an Echo II they would be willing to take some photos of and maybe jot down the cap/res/pot values and send them to me. I've been trawling eBay for a while now and missed that last few that came up for auction. Well there is one now but it's Ike $400.00. :-/
Any help anyone can provide would be most appreciated.