Super Serial Card not working, but not dead either

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Joined: Jul 21 2017
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I'm trying to resurrect an old enhanced IIe. So far, I've gotten everything working again, except for the Super Serial Card. I'm able to run a few diagnostic tools, all of which see it as an unknown card. APEX II sees it as: 44 80 168 184 56. The correct values for an SSC are 44 80 169 184 56, so it's only off by one. I'm wondering if it might be one bad chip on the board somewhere I could replace. I have a second old IIe motherboard, which I've already used to cannibalize parts and repair a bad RAM chip on the 80col card.

Any ideas? While the SSC isn't working, I can sideload disk images with ADT and audio cables (hence why I want to get the SSC running!) Any tips on what to try next?

Thanks,
maniac

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Joined: Aug 18 2017
Posts: 5
Re: Super Serial Card not working, but not dead either

maniac wrote:

APEX II sees it as: 44 80 168 184 56. The correct values for an SSC are 44 80 169 184 56, so it's only off by one.

EPROMs loose their content. Try to program this chip again.

- Ralf

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Joined: May 17 2017
Posts: 14
Re: Super Serial Card not working, but not dead either

RalfK wrote:

EPROMs loose their content. Try to program this chip again.

Assuming the card has an EPROM. Apple also shipped these cards with masked ROMs.

speedyG's picture
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Joined: Nov 16 2011
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Re: Super Serial Card not working, but not dead either

Hello maniac,
first welcome to the community...
second gratulations to the succesful solved tasks yet.....
like mentioned by yourself there are dozends of cloned copycats of the SSC...
pictures from both sides of the card ( solder- and componentside ?
several cards have been modified back in time ( adapting to special printers )...
even if mods have later been removed there might be problems:
changed chips, bad solder joints.....
maybe thgat the bufferchips for the cables (1888 or 1889 )might have been damaged by former link to printer...similar is valid if the card was exosed to rough handling... that might have damaged the crystal...

speedyG

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Joined: Jul 21 2017
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Re: Super Serial Card not working, but not dead either

Follow up - looks like RalfK was correct, the EPROM lost its mojo at some point over the last 30+ years. I was able to read it using an Arduino Mega (neat write up if anyone is interested: http://danceswithferrets.org/geekblog/?p=496). I found the original image of the ROM on this site, and the read from my chip is way off: http://www.applelogic.org/APPLEASICs.html

Anyhoo, I have it out on the window ledge, hopefully erasing right now. I'll need to figure out a trick to get 25V into it for programming, but I'm going to try and load the image back onto the chip. Anyone have any experience trying to reuse old EPROMs like this, particularly with using sunlight to clear them? Should I go for it, or just trash the chip and buy a more modern pin compatible EEPROM instead?

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Joined: Aug 18 2017
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Re: Super Serial Card not working, but not dead either

maniac wrote:

I found the original image of the ROM on this site, and the read from my chip is way off: http://www.applelogic.org/APPLEASICs.html

I often use this site when looking for ROMs:
http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Interface%20Cards/Serial/Apple%20II%20Super%20Serial%20Card/

maniac wrote:

Anyhoo, I have it out on the window ledge, hopefully erasing right now.

Probably you need not erase the EPROM. If you want to program the same bits program it again without erasing before. An erased bit in an EPROM is '1'.

maniac wrote:

I'll need to figure out a trick to get 25V into it for programming, but I'm going to try and load the image back onto the chip.

My chinese programmer (TL866CS) does not offer Vpp = 25V. My actual solution is to program a 2732 which are available with Vpp = 21V or even 12,5V. Program the whole file in the upper and the lower half.

maniac wrote:

Anyone have any experience trying to reuse old EPROMs like this, particularly with using sunlight to clear them? Should I go for it, or just trash the chip and buy a more modern pin compatible EEPROM instead?

Probably sunlight will work after some days. It depends on the intensity. Don't trash this chip! This chip will work again. Get a 2732 if your programming adapter lacks Vpp = 25V. Or use an EEPROM.

- Ralf

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Joined: Dec 20 2008
Posts: 210
Re: Super Serial Card not working, but not dead either

You will never erase an EPROM with the sun- that's a myth. Leave it out for a year, you'll see. Smile

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macnoyd's picture
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Joined: Oct 15 2012
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Re: Super Serial Card not working, but not dead either

Not true. I did it in 3 weeks, but it was only an experiment and it wasn't a 100 percent complete erasure.
Almost though. Longer might have done it. But in the end, I agree, you need a UV EPROM eraser.

BTW, if you have the code and/or want me to re-burn it for ya, let me know.

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Re: Super Serial Card not working, but not dead either

I recently purchased an EPROM burner and UV eraser off eBay for about AU$75 total. I'm sure someone can help you out for much less than that, but for me it was worth it to do it on my own, as I've been stuck needing to reprogram a couple of EPROMs in the past year or two.

You could also investigate upgrading to a pin-compatible EEPROM which doesn't need the high voltage to be written to.