Have Olympian LED Sign, ADT 502. It is 6502 driven with a ROM, RAM and VIA. Has a keyboard connector to enable entering the display message. Have no keyboard. Made a switch box and tried to get some operation but no luck. Was made by Cybernetic Data Prod which is no longer. Starting to dissassemble the ROM code. Need any info on operation and keyboard. Thanks.....

Welcome. Am working on a larger sign on an airplane right now, lets see what can be done.


1. Refer to the thread about the Microbot where we are dissembling and learning this puppy.

2. Take pictures of the front and back of the motherboard or boards. That will be a startup. Eventually, we will see about using a continuity meter to figure it out and create a schematic from it.

3. Can you dump the eprom out? Email it to me, I can host it if you wish.

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"My biggest dream in life? Building black plywood Habitrails"

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"My biggest dream in life? Building black plywood Habitrails"

Through Tony's link, I found this link:

http://www.dickwick.com/sign/

It has a DOS program and rom image. I'm not sure its the same display but it is made my the same company.

Kewl, let me see their rom, if 6502, defintiely a post and dissemble fun....

[EDIT] Tastes like 6502 in the rom....

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"My biggest dream in life? Building black plywood Habitrails"

I too have an Olympian LED Sign, ADT 502 that I am trying to repair. I have only gone as far as seeing the power supply works. It has an accessory module with a large Eprom 27xxx series. Any help or schematics would be appreciated.

Welcome ne0f1sh

Is "repair" your main goal -- simply to get the thing working exactly as it used to do? Repairs sometimes turn out to be quite easy, even when working without a schematic. But if the system is missing some components (such as the keyboard/programmer) and/or you wish to modify the way the system works then you're much more likely to need detailed information such as schematics and even ROM listings. So...

• what are your goals?
• how does the unit presently behave? Why does it seem to need repair?
• If you can provide some photos (and the numbers of the main IC's) this would help us help you

cheers,
Jeff

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In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html

Thanks Jeff, for your quick response.

Yes, I am just trying to repair this message board. It had previously been working just fine, and when it stopped, it looked like there was no power, no lights. This unit ran a continuous loop of messages, which I figure are on the E-prom located on the accessory module. I do not have a keyboard nor do I want to change anything.

Next time I am the shop I will shot some pics if that helps. I did notice that there was a slight haze on the inside of the plexiglass face about 3/4 way down the board. The power supply works, I saw about 12v at the filter cap.

Jacob

I too have an ADT-520 that is still working. Back in the day I was able to get a manual and a keyboard for it, but it didn't come with an accessory module - just the header. I've looked at the pinout and it doesn't make sense: The header is connected to the data side of the 6522, and only a single address line and reset on the 6502. The port side of the VIA seems unconnected to the 6502 - I didn't check if it was going straight to RAM. I don't understand how anyone could hook up a 2400 baud UART to the 6502 with this pinout. Anyone with an accessory module who can share a schematic or pics?

Can you post an attachment that can be opened with non-Microsoft software? Perhaps we may be able to help.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Open Office 4 opened it for me. Here's a snip of the spread as a jpeg:

I don't know how to make it large enough to be legible inline in this post, but you should be able to magnify on your end.

Mike

Here's a tab-delimited version

I opened it in LibreOffice Calc which is free for Linux.


The connection list is incomplete, but it looks like the 34-pin is not for the 6522, but instead goes to the CPU bus and not 6522 I/O lines.

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

I believe that I checked all the 34-pin header pins against both the 6502 and 6522 - only the ones that were connected are shown (I omitted the NC's in column 2). I also thought I compared the 6502 pins to the 6522 pins. I'll redo the table next week and maybe put together a schematic to make things clearer.

I'll have to see if I have an EPROM reader lying around - maybe the 6502 code will shed some light on what is expected from the accessory port.

Here's an updated pinout - I should be able to post a schematic tomorrow. I didn't bother pinning out the 6502 memory interface.
I've extracted the ROM image - I can send it to anyone interested in disassembling it.