Jump to content
IGNORED

Just bought an Apple II (Model A2M001 - mfg date Feb 1979). Can't type and boots to monitor prompt. Need help.


aguyandhisappleii

Recommended Posts

1 hour ago, MarkO said:

That can lead to the 74LS125 being Blown Up...    

 

I ALWAYS, remove the Disk ][ Controller and turn Upside Down, to plug in the Drive "correctly"..   This I learned to do after Blowing Up 2, of the 74LS125s...

 

The Clicking is the Apple ][ Power Supply, shutting down to prevent damage...

 

MarkO

Yes. I heard and am worried about that. When I get the chance, I'll open up the drive to see if I did indeed bust any chips. Since my Apple II was a non-autostart one, the drive never even spun even when I got it connected properly (I didn't issue the commands for accessing the drive - I also didn't know these older IIs don't automatically boot from the drive), so I'm hopeful nothing got blown up but I don't know if that's how it works. As for the keyboard, I'm going to buy a replacement for the encoder chip (an MM5740AAE/N) to see if that gets it working again. Since I have no other keyboards, chips, or Apple II hardware to test with, that's pretty much the best I can do.

Link to comment
Share on other sites

On 12/26/2022 at 11:02 PM, aguyandhisappleii said:

Yes. I heard and am worried about that. When I get the chance, I'll open up the drive to see if I did indeed bust any chips. Since my Apple II was a non-autostart one, the drive never even spun even when I got it connected properly (I didn't issue the commands for accessing the drive - I also didn't know these older IIs don't automatically boot from the drive), so I'm hopeful nothing got blown up but I don't know if that's how it works. As for the keyboard, I'm going to buy a replacement for the encoder chip (an MM5740AAE/N) to see if that gets it working again. Since I have no other keyboards, chips, or Apple II hardware to test with, that's pretty much the best I can do.

Two sites you need to know about for locating Electronics are "Find Chips" and "Octo Parts"..

 

Looks like there are plenty of replacements available...

https://www.findchips.com/search/74LS125

 

 

 

BTW, did you ever get an account to Apple Fritter??

 

MarkO

Link to comment
Share on other sites

7 hours ago, MarkO said:

Two sites you need to know about for locating Electronics are "Find Chips" and "Octo Parts"..

 

Looks like there are plenty of replacements available...

https://www.findchips.com/search/74LS125

 

 

 

BTW, did you ever get an account to Apple Fritter??

 

MarkO

I was just going to buy the part on eBay since they’re only a couple bucks. Is that a bad place to buy it from?

 

No, I never did, although it’s been a while since I last tried.

Link to comment
Share on other sites

Buying ebay chips from a seller that is not in China is probably safe.  Or at least safer than buying say, Ali Express chips.  Some sellers from China sell remarked/fake/bad chips.  For chips that are still in production today (like many of the "LS" logic chips, I prefer to buy from a known electronics warehouse like mouser or digikey.

  • Like 1
Link to comment
Share on other sites

On 12/28/2022 at 4:08 PM, aguyandhisappleii said:

I was just going to buy the part on eBay since they’re only a couple bucks. Is that a bad place to buy it from?

 

No, I never did, although it’s been a while since I last tried.

eBay??  Not necessarily..  You can start there..   

 

You should contact Apple Fritter again..

 

MarkO

Link to comment
Share on other sites

5 hours ago, nick3092 said:

Buying ebay chips from a seller that is not in China is probably safe.  Or at least safer than buying say, Ali Express chips.  Some sellers from China sell remarked/fake/bad chips.  For chips that are still in production today (like many of the "LS" logic chips, I prefer to buy from a known electronics warehouse like mouser or digikey.

My preference too, but eBay does favor the Buyer, so you do have a lot of leverage when buying things..

 

Jameco has the 74LS125s for less than a $1.00 each, but I believe you need a $5.00 order minimum..

 

MarkO

Link to comment
Share on other sites

I'm handling "spare parts for the future" by making sure I have several of each and every part on the motherboard. Easiest way is buying a few boards or complete computers and setting them aside. This is good for the custom chips and some discrete parts or the timing GALs. Of course if I pull from the spares then I have to refill it by buying it. But I don't have to put a fire out. The part goes on a list, and when it's convenient I buy it.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...