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tezza
September 25th, 2008, 01:20 PM
Hi,

Still working on getting this platinum 100% working. It is working but it has issues. The issue seems to be related to expanded (above 64k) memory and the possibly the 80 column mode. Here are the facts...

When Prodos 1.1 boots, it puts a string of "SSSSSS" where the white graphic lines in the display should be (see pic). Switching to 80 column display doesn't work but instead throws you into the monitor program.

This is what it looks like as it boots..

http://classic-computers.org.nz/blog/images/08-09-26-platinum%20issue-prodos-boot-faulty.jpg

This is what is should look like...

http://classic-computers.org.nz/blog/images/08-09-26-platinum%20issue-prodos-boot-good.jpg

The final menu screen is also messed up, with SSSSs being where the white graphic line should be.

Sounds like the 80 column, 126k Card in slot zero (the Aux slot), right? Or maybe the video IC? But consider this...


Swapping the card with a perfectly good one from my other platinum board exibits the same symptom (so it's not the card)
Substituting all the socketed ICs in the system doesn't fix the problem
The computer will autoboot standard (64k) Apple games (like Apple Panic) and play them perfectly ok. The graphics below 64k appear fine.

The problem seems to manifest itself when the system wants to use that extra memory. ProDOS 1.1 needs it, although even with the fault it does complete it's boot. It just there are S's intead of white lines on the display and it won't move into 80 column mode. The fact that it does recognise and use some of the memory would indicate at least some above 64k addressing is taking place. If you remove the card, Prodos simply complains that it needs 128k to boot.

A theory? Could it be badly oxidised connectors in the card 0 slot (this is part of the "haybarn" haul after all)? Certainly each connecting strip has a very black stripe of oxidation running down it (but then the slot in the good platinum looks similar). I tried to buff these up a bit with some fine sandpaper but that didn't make any difference. However, I did freshen up the connectors on the card itself in this way.

This weekend I'll get hold of some of that gel Dwight suggested for just this kind of problem (it should fix my ZX-81 expansion pack issue too).

Anyone got any other ideas or alternate theories? Or any other diagnostic tests I could do?

Tez

billdeg
September 25th, 2008, 06:08 PM
try a higher version of pro dos

tezza
September 26th, 2008, 03:45 AM
Hi,

A theory? Could it be badly oxidised connectors in the card 0 slot (this is part of the "haybarn" haul after all)? Certainly each connecting strip has a very black stripe of oxidation running down it (but then the slot in the good platinum looks similar). I tried to buff these up a bit with some fine sandpaper but that didn't make any difference. However, I did freshen up the connectors on the card itself in this way.

This weekend I'll get hold of some of that gel Dwight suggested for just this kind of problem (it should fix my ZX-81 expansion pack issue too).



Well, that didn't work--must be something else. Like the IOU chip. Soldered into the board ..arrgg :(

Tez

bugman2112
September 26th, 2008, 05:52 AM
This may be a stupid question, but did you try the built in self diagnostics upon boot? These actually work pretty well for diagnosing bad RAM and other issues. If nothing shows up there, other disk based diagnostics work pretty well. I recommend Master diagnostics //e and the apple dealer diagnostic disk. The fact that you can boot should make this easier to figure out.

Druid6900
September 26th, 2008, 11:08 AM
Maybe we should sticky this;

Apple //e in-ROM diagnostics

Press Ctrl-Open Apple-Closed Apple-Reset to run diagnostics and replace the defective IC shown on the screen.

tezza
September 26th, 2008, 02:45 PM
Maybe we should sticky this;

Apple //e in-ROM diagnostics

Press Ctrl-Open Apple-Closed Apple-Reset to run diagnostics and replace the defective IC shown on the screen.

It wouldn't hurt to sticky it. I do remember this being mentioned in another thread, but it slipped my mind. Thanks for the reminder.

Ok, doing this (after figuring that closed-apple was the option key on the platinum) the screen filled with pretty colours...these flashed and cycled and then just three letters...

IOU

Appeared in the middle of the screen. It was as I suspected.

I put my other platinum through the same test. The words "System OK" appeared in that case.

Reactivemicro.com is one source of can think of for chips like these. Anyone know any others?

Tez

bugman2112
October 3rd, 2008, 06:40 AM
I just found this site. Looks like they have many, including the IOU, in stock for the Apple. Looks like a great resource. I may pick up a few items just to have spares.

http://www.arcadecomponents.com/index.html

tezza
October 3rd, 2008, 12:37 PM
I just found this site. Looks like they have many, including the IOU, in stock for the Apple. Looks like a great resource. I may pick up a few items just to have spares.

http://www.arcadecomponents.com/index.html

Thanks for that link. I've already ordered the spares for elsewhere but I'll bookmark this in case I need it again. The prices are very reasonable.

Tez

channelmaniac
October 9th, 2008, 07:45 PM
Wow,

Thanks guys!

I found your post when searching for my company name in Yahoo. I like to do that to see how far the word has spread and to see what's being said.

I keep all my repair logs for various games & systems online on the NLG forums under a special section. Maybe it will help you keep some of the old systems alive.

http://newlifegames.net/nlg/index.php?board=19.0

BTW: I used to work for a grey market Apple repair depot back in the mid 90s and did a LOT of repair on the old Macs and Apple II series.

Raymond

Druid6900
October 9th, 2008, 07:49 PM
Not to worry, Raymond, I put your site down as a link to find parts for old systems long time ago on this site.

You probably don't remember me, but, I was in touch with you about getting some RAM chips for an Apple /// a few years back right before you got a load of computers that some guy was hoarding in a barn or something.

channelmaniac
October 9th, 2008, 07:58 PM
Yup!

This guy lived in a loft over a business and had little paths going from area to area. Everything else was filled with bits of Apple history. Slowly a friend of his has been helping him dig out from under it. I've bought a lot of bags of pulled chips from them as they have been selling boards to scrap metal folks.

I ended up with a couple of those 32k DRAM chips about 3 months ago but have no way to test them. He was supposed to have a couple of boards filled with them. I don't know if they'll ever find them.

Druid6900
October 9th, 2008, 08:00 PM
I found a tube of 20 a couple of years ago at a place that didn't know the true value of the chips, so, I have 32 x 1s to burn now LOL

channelmaniac
October 9th, 2008, 08:08 PM
Nice! Now I know who to send people to ;) hehehehe