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I'm trying to restore my original Apple I which I bought from Steve Jobs at the Homebrew Computer Club. I have a friend who is an expert engineer working on it. I have not run the board for 40 years but he has made good progress and got the board running. (see attached).
Here are my questions:
When I pulled the first RAM chip, the leads were very tarnished, probably silver plated. When I attempted to install the IC, several of the leads on one side were very weakly attached to the body, to the point insertion would surly break a lead. All of the remaining 7 DRAM parts look to be in similar condition and I would recommend changing all 8 of them. There is solder evidence on some of the DRAM socket pins that that they may have had trouble with poor connections in the past (see attached). He recommends finding the original Mostek MK4096N-11 RAM ICs if possible.
1. Does anyone know where to find these Mostek RAM chips?
2. If they don't exist can you recommend an equivalent chip?
3. He also recommends we add another 4K of memory. Is that a good idea?
4. Can someone remind me of if BASIC comes installed on the Apple I?
5. I recall the high res routines were available on Cassette tape. Was there other software?
6. I'm thinking about auctioning the board and wondered if anyone knows how important the Cassette board is in an auction? I have one but getting it working will take some effort.
Thanks for any insights you can provide.
Sincerely,
Mitchell Waite
1 & 2) I have some of these RAM chips that I extracted from an old DEC board. They were soldered onto the board, so the leads aren't "Factory perfect" but they are straight and solid with the correct dates. I haven't thought about selling them, but I do have 3 complete sets to populate Apple 1's. There are equivalent chips, but this will likely deduct from the authenticity of the board, although the board itself is the real prize.
Over and above the IC's, the sockets themselves show considerable corrosion and might be problematic. Consider cleaning those if you're conducting a restoration. (make sure there is no conductive (corrosive) film between the pins.)
3) Filling the memory will give you the best user option if you plan on making this a working demo. (IMHO)
4) Basic doesn't come with the Apple 1 but is available as a cassette download.
Or, you can enter it by hand here: http://www.brielcomputers.com/basic_dump.txt
5) ...
6) Including the original cassette board would be best if going to auction the Apple 1. (IMHO)
Wish I could afford an original ...
The leads on those ICs are solder plated Kovar but the solder oxidizes black over a long time. I'm not sure of the best chemical to clean the leads but contact cleaner helps. I have never seen those types of leads actually weaken from age.
I am an original owner of an Apple 1 and I know of only one other original owner so Apple 1's in the possession of original owners are very rare and desireable to collectors. If possible you should keep all parts you replace on the board with the board and keep a record of work done, you should have your friend document exactly what he did to get the board operational. I restored an Apple 1 for Woz and provided him a notarized report documenting the work done along with all replaced parts. You should be prepared to document the details of when and where you acquired the board.
Hello Goofy167,
I´d recommend to get contact to the member Corey986 here and listen to his advices....
he has most expertise with that topic and he restored in last years several Apple-1
boards previous - before they have been sold in an auction at Sotheby´s or other facilities.
So he is the one you want to talk with - due to the fact that he has most experience
in handling such old systems.... and therefor is familiar with that what you might call
the "normal disabilities by age" of that systems and handling trouble by keeping track to
preserve worth of the system .....
welcome to the board
speedyG
I live in Europe / Germany and am often handling with very old IC´s and i also
still make my own pcb´s by etching.....
At the one hand for example it´s very difficult to apply photograhical sensitive spray to copperboards
if they have smallest portion of oxydation on the surface and here they distribute the so called "Polibloc"
from the manufacturer "Seno". That bloc is like a "soft stone" and it removes any kind of oxydation but
with far less impact than if you would try to clean by wet sanding. You can even cut this block to
smaller pieces with normal knife.
Soon i discovered that this block also removes any kind of oxydation from old IC-pins perfectly
and leaving them in nearly factory fresh clean shine.
Unfortunately i have´nt discovered any distributor for this stuff in the U.S. or Canada till now.
A hint at least:
Check this link to the German distributor and sales information:
http://www.conrad.biz/ce/de/product/529419/Polibloc-Weiss-SENO-2003-Inhalt-1-St;jsessionid=9D24CA655D5E577D3BDD45A3B4A10C38.ASTPCEN28?ref=searchDetail
maybe you will be able to detect a source in USA or in Canada.
I´d recomend this "Polibloc" in every case of removing oxydation in a restoration task.
sincerely speedyG
First things first...
Welcome to Applefritter...
There are a lot of things that can go wrong on a 40 year computer. Too bad about those traces that affects the value. As I always say, all collectibles have a common thread. A perfect condition Action Comics #1 could go for millions and a poor condition one could go only a few tens of thousands. The only thing that trumps this is provenance.
For an auction, you need to show the system running basic and a basic program. This shows the system actually works, a barely working system can run the woz monitor, but it's a long way away from running basic.
For the RAM chips. They can get black crud. I have used an art eraser in the past, but you risk breaking the legs if you aren't careful. I have been told Tarn-X works by someone else on TI chips which have the same problem. To be honest most of the systems I have worked on have been in a controlled enough environment to limit the black crud to only the exposed areas of the chip and the actual connection points haven't been an issue.
How was your board stored? Did you ESR the caps or are you just hoping they won't fail or catch on fire while you are working? Did you reform the caps and what did you do for load on the supply? Did you chemically neutralize the board to prevent further problems?
Cheers,
Corey
I happened to have re-read my post and realized something I should clarify...
You may not have understood my comment on value. I think you are saying that you are an original owner. So it sucks about the cut traces that affects the value a lot, but being the original owner is part of the provenance and usually means you have great documentation to go along with the unit. Even better if you were connected to early Apple or Jobs and Woz.
Cheers,
Corey
OK, this thread has got me interested. I just ran out and bought some Tarn-X. I have some TI 74xx chips from the 70's with the black crud I was going to use on my Scelbi 8B project. I'll try the Tarn-X out on those and report back tomorrow. Maybe that will prevent the need for Goofy167 to risk mechanically cleaning the crud off the ram chip pins.
Cheers,
Corey
Remember, Tarn-X is an acid. Be sure you neutralize the acid left behind when cleaning.
Tarn-X also causes micro pitting of the metal surface and this pitting acts like a sponge and
will cause tarnishing of the pin much more quickly.
I was planning on a distilled water bath with a low percentage of tarn-X, then another soak in a new water bath then a soak in 99.9 percent ISP.
Figure any micro pitting is better than a broken pin. As I said I usually use an art eraser. This is an experiment for the exact situation about which is the pins are weak and you can't risk breaking them.
Cheers,
Corey
Thank you Corey for all your great advice. The board works, we got the monitor to show up though a few characters are missing which I think is do to some bad memory.
Tarn-X sounds like a great solution to the tarnished chips and will try it.
The original caps had a acceptable ESR so powering it up was not an issue.
What does chemically neutralizing the board entail?
There is a great story that goes with this board and when I finished writing it I'll post it hear as it will make good reading.
I'll email you later today. It's too complicated to explain and also requires the board be inspect to make sure components are still sealed.
Thanks to everyone for your recommendations. We don't think its wise to try and clean the board since its too easy to damage. Plus the more original the better, right?
We have the board running but have determined a number of small issues and parts that need replacement and would appreciate any advice.
1. A few of the memory chips are bad: The original is the Mostek MK4096N-11 16 pin 4K DRAM and we can't find this chip.
Is the following replacement okay?
NTE2104 - IC-MOS 4K DRAM
http://www.vetco.net/catalog/product_info.php?products_id=2793
2. We need a few DRAM sockets. They are 16 pin sockets. I have not located exact replacement sockets but these will work.
Close match
http://www.jameco.com/1/1/106-16lpd-pin-low-profile-0-3-inch-wide-ic-socket-high-pressure-contacts.html
Not as close
http://www.digikey.com/product-detail/en/assmann-wsw-components/A16-LC-TT/AE9992-ND/821746
Any thoughts on these sockets?
Mitch
Please don't put an NTE chip on an Apple 1!!
I'm sure you can find a Mostek chip with some searching...
What is wrong with the socket? They're not great sockets, but I've never seen one that needed replaced, unless it's the keyboard socket, but you said a few...
Qubie please tell me where on the Internet to find the Mostek 4K MK4096 DRAM. I can find 16K all over eBay but there are no 4Ks showing up for me. Maybe you have a better way to search?
Mitch
PS Whats so bad about using a replacement? Is it de-kosher-izing the board?
Just kidding about the NTE part. Not sure where you would find a Mostek part, those are nearly impossible to find nowadays.
I don´t know what you expected.... but if you expected to find electronic parts used in a computer from 40 years ago
in the electronic shop "round the corner" you´ll get quite disapointed....
it´s like searching for parts of a car manufactured in the time before WWII!
even at ebay such "obsolete" parts only show up 1 or 2 times a year from a recycling yard if you are lucky....
as far as i know unicorn electronics still has them in stock :
contact adress:
Unicorn Electronics
1142 State Route 18
Aliquippa, Pa. 15001
Order 800-824-3432
Fax 724-495-7882
RAM is offered at this page:
http://www.unicornelectronics.com/Apple1/apple1parts.html
another source of information on obsolete parts is:
https://www.rocelec.com/about-rochester-electronics/distributors/
speedyG
None of those sockets are a close match. You can't find the TI sockets anywhere except on eBay or a surplus provider and even then the part number for the socket is the same but they changed the design over time.
The sockets can be rebuilt. They can be disassembled on the board and repaired. Not an easy task.
My expectations re finding original parts are between "very difficult to find" to "impossible in my years left on the planet". I have a message into unicorn to determine if their $666.66 Apple 1 parts kit contains original parts or modern replacements (most likely) and I'll let the group know. Also will try the other source, thank you.
Mitch
Unicorn is pretty clear about what you get in terms of manufacturer and date code, so shouldn't be any surprises there. In terms of that RAM you'll get MK4096 with a 1977 date code which isn't perfect, but isn't terrible if you're in a hurry.
Wendell thank you for the great advice. I didn't realize that you were the Windell Sanders who was Apple employee #16. What an honor!
Goofy167,
I would try Unicorn electronics for most/all Apple I parts.
http://www.unicornelectronics.com/Apple1/apple1parts.html
They are generally a later date than 1976, for example the 4K DRAM i purchased are 1977, although I have since located some gold/ceramic 1976 Mostek parts that look a treat.
Cheers, Martin...
of course you noticed posting #17 in this thread ???
Ahoy speedyG,
Having read through the answers, there was some sort of delay in updating my browser.
When I replied I was the last answer and your reply was not present.
I have cleared the cache and hopefully will prevent me from supplying redundant information.
My sincere apologies.
Martin...
Hi Martin
Thanks for the link to the Unicorn RAM chips with the 1977 date stamp. I totally missed that.
Mitch
Hello Mitchell,
It was the first given link in the mentioned posting # 17.
sincerely
speedyG
Thought I'd give a progress report on getting the Apple 1 board working. We are getting there, right now waiting for a set of date 1977 MK4096 memory chips from Unicorn. If any of you brilliant fritters have any ideas on the problems below I would love to hear your thoughts.
Mitch
3-6-16
Progress report:
Still have a problem with the terminal display showing about 1/8 of the characters incorrectly on power up. Repeated power cycling causes more, up to 50%. Of the characters to display incorrectly. The problem is probably related to the speed the power supplies rise and fall causing some data retention not clearing the display MOS memory. Swapping the MOS shift register memories does not change the problem. The problem may not affect the operation of the system monitor… TBD.
Decided to connect the keyboard and add the missing clear screen switch to the KB interface board. Powered up and the clear screen switch worked but no monitor cursor. After some troubleshooting, fount the keyboard reset switch was broken and permanently resetting the board. Replaced the switch with a temporary switch and powered up but still no cursor.
The micro clock and data lines are showing signals but some of the address lines look suspect. It is possible the RAM chip was hit with ESD static during handling and the rework or other RAM chips could also be bad… replacement will tell so we are back on hold for now. (MW: Larry was able to add a wire to get the broken pin fixed.)
2-28-16
Yesterday, I powered up the board after replacing the crystal. While checking the power supplies, +5 was good, I noticed the 12V transformer was getting very hot. Discovered a shorted diode in the power supply, which I replaced with the same type I had. After correcting the short, the transformer appeared to have develop an internal short between a turn or two. Fortunately, I had a similar 28V transformer and replaced the defective one. As a safety precaution, I also added a series fuse in the AC supply. At that point the +/- supplies were up and running. The power supplies had no ripple noise and the electrolytic caps appear good (they are good quality Sprague parts).
Next, I connected the video to my capture board and found the expected flashing “_@_@” pattern but many of the characters were incorrect. I removed some of the ICs and cleaned the pins with contact cleaner and the problem reduced to only a few limes of incorrect characters. I am about half way through the cleaning process at this point.
I hope to get some time on the board later today.
LB
OK, I have to ask.
Which video capture setup are you using? I've been trying to find one that works with the Apple-1 video for years and none of the ones I have tried worked.
Cheers,
Corey
This is the progress report on the Apple 1 we are restoring. I'm wondering if anyone has any insights as to what our problem is. We think the 6820 PIA may be bad. But finding an original looks hard right now so we are going to try the 6821. Will this work? The following is from Larry Brown the engineer doing the restore.
Thanks, Mitch
I’ve been working on the board for a few days but have not had much success. The processor appears to be running and the video display also appear to be working but the data from the character data 6820 PIA to the video display doesn’t seem to work. Also the keyboard data doesn’t seem to reach the processor but it appears to be polled so there in no interrupt to confirm for sure. The PIA IC also has several wires running to the IC socket in the breadboard area so static damage is a possibility.
At this point, all I can come up with is to replace the 6820 PIA. Apparently they were long ago out of production, replaced with 6821 and the newer 68C21. Next thing to do is order a test 6821 IC. If it fixes the problem, we can search for a vintage part. Just in case, a spare 6502 would be good to have. This is turning into quite a project.
6821 PIA
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_43596_-1
http://www.ebay.com/itm/2x-MC6821P-EF6821P-DIP-40-PERIPHERAL-INTERFACE-ADAPTER-PIA-HD6821P-/121376978673?hash=item1c42a1b6f1:g:B5gAAOSw7I5Ts78f
Supposedly pin compatible 6502
http://www.mouser.com/ProductDetail/Western-Design-Center-WDC/W65C02S6TPG-14/?qs=sGAEpiMZZMtVFuKNr6IGvpdkwXR9vVB1
LB
Hi Corey
Larry has his Apple 1 plugged into a NTSC video board on his PC. Is that what you need details on?
Mitch
That may be the difference. I'm looking for a usb solution that works with a Mac. I'm pretty sure a hauppague video card would work.
6821s amd 6521s work, but they may come out of reset a little differently than the original 6820, so the systems initial response to reset may be a little different than what you would experience with a 6820. I would stay away from the modern WDC parts for the Apple 1 application, as they are designed for much higher bus speeds (14MHz) and the fast edges may result in problems on the Apple 1 bus.
Jameco has 1Mhz 6821's listed for 3.95 each.
regards,
Mike W.