This seems not to be working. It's been a while since I brought up CP/M on either of my Apple IIe and I think it had the 'enhanced' upgrade done since that time. Now on both of my enhanced Apple IIe machine the Appli-Card no longer works. Is this a known compatibility issue or has mu Appli-Card gone south (so to speak)?
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There is a bug in the Applicard which is known to kill the MMU in a //e under certain circumstances.
I never knew that, I'll be sure to only test the ones I have here in a 2+
Petar Puskarich and Ian Kim on the Facebook Apple II Enthusiasts group could fill you in on the details of the bug.
I bought an Applicard DOA and needed to replace the Z80 chip . It works on my enhanced //e just fine. Make sure it's a Z80B for 6MHz
Larry G
It does have a Z-80B in it.
The symptoms are, when booted with the CP/M disk the disk is read, then the system resets again. This will just loop indefinitely. The same thing happens on two different machines. I tried un-enhancing one of the machines, but the same thing occurred. Both machines work just fine with Prodos, so the MMUs are not the issue.
It could be a bad CP/M disk. I'll try making another at some point to see if this clears things up.
Are you sure it is the right CP/M disk? I don't think the one for Microsoft Softcard and compatible cards will work with an Applicard.
yes it has to be cp/m for the Applicard not SoftCard. The symptom of a dead AppliCard is the Applicard cp/m boot disk keeps rebooting like you're seeing.
Larry G
Yeah, it's the CP/M for the Applicard alright. As I said, it had worked just fine before.
So, at this point I've tried everything I can without starting to replace chips on the Applicard, including making a new CP/M disck, trying different Aplle IIes, de-enhancing, and re-seating all the chips on the Applicard. I'll find anopther Z80 and try that out.
Weird how stuff like this can just happed out of the blue.
I keep a large assortment of 74*** chips on hand for just such an occasion. (said in my best "Foghorn Leghorn" voice).
Here was another confirmed case of bad Z80 on an Applicard from last summer:
http://www.vcfed.org/forum/showthread.php?64332-Appli-Card-(Z80-Card)-disk-images-Apple-IIE&highlight=applicard
Larry G
[quote=retrogear]
Here was another confirmed case of bad Z80 on an Applicard from last summer:
http://www.vcfed.org/forum/showthread.php?64332-Appli-Card-(Z80-Card)-disk-images-Apple-IIE&highlight=applicard
Larry G
[/quote]
Those are exactly the same symptoms I'm having.
A new Z80 will be on the way shortly.
I finally received the new Z80s last night. That took a loooooong time, considering they came from the UK to Canada. Normally only about 1 week – not 3.
Anyway, popped a new one in just a minute ago and everything is hunky-dory now. It was the Z80 that was the issue.
Now my question would be - why would a Z80 ever die? I have never had this happen to any other CPU - ever! Not 8080s or 6502s (and it’s derivatives) or 6800s or 1802s or anything else. Does the Z80 have flaws? Is the Appli-card doing something funky?
I’m just not used to the concept of a chip like a CPU failing. It’s not like they should be under physical/electrical stress.
Weird.
Oh, and I really hate this new forum software. Why did the admins go with this? It's just awful!
[quote=BillO]
Oh, and I really hate this new forum software. Why did the admins go with this? It's just awful!
[/quote]
But we LOVE it ! <grin>
Regarding those dead Microprocessor chips... If you see enough of them, you're bound to see a few dead ones from time to time.
Memory & TTL chips, all the same. Sometimes "time" alone is the killer. I can only guess that with temperature variences, expansion and contraction of the materials that make up the chip and impurities during manufacturing all contribute to these flaws. I suppose that if the legs can rott off by simply sitting in carbonized foam, pretty-much anything can happen. Maybe that's why Ceramic chips usually hold up better to extreme environments.
I've run into dead or dying 6502s a few times. Any chip can fail
Dead or dying 6502?
Hah! Never!
I've blown up 1 or 2, but never seen one roll over and die. Even some of my own wonky designs have been tooting along for the best part of 40 years now. In fact I just designed 2 new 6502 systems in 2018. I must have had more than 120 6502/6507/ 65C02/ WDC65C02 processors go by under my eyes since 1978 or so without a single un-forced demise. Of course, it could be that I'm lucky that way. Lord knows I have a dearth enough of luck in my life.
I am that guy that gets to the end of his driveway every day and has to wait for 3 cars to go by before puling out onto the road ... the only thing is I live out in the woods and have about 5 cars total pass my driveway each day :-(