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intric8
Seattle, WA, USA
Website

Posted Tue Nov 23, 2021 9:57 am

I had the pleasure of corresponding with Greg Tibbs - the designer and inventor of the Rejuvenator upgrade board for Amiga 1000 computers - for about a year and a half.


But first, I had to actually find him. And he was one of those folks who was very intentionally "off the grid" - no Facebook, no Twitter, no LinkedIn. Nada. I combed through multiple State business records, contacted Eric Schwartz and the Dayton Amiga Users Group members, Ben Williams of Black Belt Systems (Greg used Ben's software to draw the Rejuvenator schematics on his Amiga 1000) and even Scott Bennett of Expert Services - the original manufacturer and retailer of the board.

After several months of intense searching I finally found a name with an address on a very sketchy looking "white papers-styled" website.

Resigned to failure, my last recourse of action was to write all of my intentions down to reverse engineer the board in a letter (remember those?) and put it in an envelope. I then mailed it to the address I'd found online. I assumed it would be undeliverable and bounce back to me in a week or two stamped, "Return to Sender." My thought was I'd keep that sealed envelope in case I was ever later sued over the project so I could unseal it in open court showing that I'd tried my best. That was my legal defense. :D

In the email at the very end I left my phone number and one of my personal email addresses.

About a week went by.

Then, on May 11, 2018, at 2:34 PM PT I received the following email, which gave me chills and made the hair on my arms stand straight up:


Hello Eric,

I received your letter today.

Yes, I am the person you are looking for. I designed the Rejuvenator.

I quit designing Amiga products after getting stiffed by two companies. That was a long time ago. I threw away my last unpopulated Rejuvenator circuit board about a year ago. Scott Bennet (formerly of Expert Services, which I believe is defunct) held on to the master artwork. The last time I talked to him, about 2000, he was going to try to get someone else to manufacture it. Expert services put all the money into their retail store account against my wishes and they spent it on store stuff and all I got was an A3000 for my efforts ( on a 50-50 profit split deal. They owed me over $50K. So there was no need or desire to stay in contact with them. I designed the original HAM-E for Blackbelt Sysatems and they quit paying royalty payments after it hit the market. I got rid of my A1000 in the early 2000s. The circuit board was designed on an Amiga using BlackBelt Systems PC board software. All the floppies went bad and there was no other media. I do not have the schematics anymore nor any electronic or written documentation. If you want to reverse engineer it, then go ahead. You have my blessing.

The original A1000 Rejuvenator was a 4 layer board. I wanted all the parts on one side for manufacturing costs. The only issue is there has to be connection to the custom chip sockets and those six rows of pins were hand soldered. I used holes in the board for the pins to go from the motherboard through to the Rejuvenator connectors for the reason the two 40 pin chips could overlap the connectors and save board space and that to add the A2000’s video slot and leave room, it had to fit closer to the motherboard to allow space for the video card. There was only one revision and there was one bug on an internal layer at the video card connector where one of the digital colors was shorted to the ground plane. Once discovered, the pass through hole that was shorted was drilled out and the color signal wire run to the video card pin using a jumper wire.

There was one wire to go from the daughterboard to the motherboard to sync the main timing clocks after a reset. There was a 7474 D latch triggered by the motherboard reset signal.

The DRAM chips used were unpopular in DIP format and were discontinued after a couple years. ZIP ram may be still be available. To prevent ringing, the dram data lines had to have 33 ohm resistors in line.

There was one or two Custom PAL chips to control the timing and the real time clock and the ROM chip. The PAL chips were done on a PC on 5.25 inch floppies, but they are long gone.

The biggest issue was power distribution. The Commodore daughterboard kept areas separate, but Commodore engineer George Robbins told me to merge them into a single power plane in the Rejuvenator. That was bad advice as I used heavier power traces than the motherboard and it created a mild instability The required jumping the motherboard power traces at the CPU to really fix. This showed up most when sidecar devices were connected. The original prototype was hand taped two layer board and it worked better than the fancy 4 layer board.

Another issue is where to get the two custom chips needed, Fat Agnus and ECS Denise. Without FA, at least, there is no Rejuvenator.

If you want to talk, I can be reached at 937-xxx-xxxx.

Greg Tibbs




The fact he remembered all of those tiny details 30 years later tells you something about his keen intellect.

I called him later that day and we spoke on the phone for an hour.

And that was the beginning of our correspondence. The public release of all of the files last weekend of his Rejuvenator kind of hit me funny. Part of me was so excited to have hit this incredible milestone after three years of trying. And another part of me felt like looking back; like, I wasn't ready to entirely let go. I just wish he'd been here to see this.

I had originally planned on getting on an airplane when this day arrived so I could meet him in-person somewhere in Ohio and buy him dinner and listen to his Amiga stories. He was only in the community for a little while, but while he was there he was Fast and Furious.

I have at least one more story of his I'll share next time if you all like this kind of thing.

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Zippy Zapp
CA, USA

Posted Tue Nov 23, 2021 10:13 am

intric8 wrote:
Tue Nov 23, 2021 9:57 am
I have at least one more story of his I'll share next time if you all like this kind of thing.
Yes please. I love these kind of stories and details. Very sad for him not being able to see it but I know if it was me I would be honored that someone carried on the legacy decades later...

Nice work. An A1000 is something that has been on my list for some time. This project puts it even higher. Might have to let go of an A1200 and an A500 to make room.

User avatar
nonarkitten

Posted Tue Nov 23, 2021 10:23 am

What's heartbreaking about this, is that not only was he shafted and gave up on the Amiga, he never had the chance to see his creation come to life again. Perhaps even more telling that this thread of use and abuse within the Amiga development community exists to this day, forty years later, all the way from the bottom up.

User avatar
intric8
Seattle, WA, USA
Website

Posted Tue Nov 23, 2021 10:44 am

nonarkitten:
he never had the chance to see his creation come to life again
Not to total completion, no. He did get to see the board reverse engineered, just never the total package with the 4 PAL chips, which we originally thought might be read protected even though he was certain that wasn't the case. Ultimately, he was right.

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Sophia82
Website

Posted Tue Nov 23, 2021 11:24 am

Too bad things didn't work it as he planned. Sometimes it goods to give more faith in your engineers/designers instead of only cutting costs etc. I had a great time reading this correspondence and I'd love to read more of this kind of stories. Not too long ago I came back to getting into Amiga hardware and I'm so happy I did so :)

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obitus1990
New Orleans, LA, USA

Posted Tue Nov 23, 2021 3:02 pm

intric8 wrote:
Tue Nov 23, 2021 10:44 am
nonarkitten:
he never had the chance to see his creation come to life again
Not to total completion, no. He did get to see the board reverse engineered, just never the total package with the 4 PAL chips, which we originally thought might be read protected even though he was certain that wasn't the case. Ultimately, he was right.
Great story, thanks for sharing it, Eric.

So the PALs were not read-protected? What kind of protection did they have on them, if you don't mind saying (or repeating if it's already been said, and I've lost track)?

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EzdineG
Springfield, MO

Posted Tue Nov 23, 2021 5:04 pm

They weren’t protected. It just took a very specific time-correct piece of equipment to read them.

Modern readers were returning all 1’s, which appears just like protection.

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Dynamic_Computing

Posted Tue Nov 23, 2021 7:38 pm

Fantastic story! It is so wonderful that you were able to reach out to him after all those years, and he could at least glimpse his design coming back to life. I was not aware that he designed the HAM-E also! I know there is a story in there about how Commodore killed that project, but nobody seems to know all the details. It was rumored back in the day to being way to close to AGA, and they did not want that damaging their A1200 sales, but that may have just been rumors.





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