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Apple ii+ ram issue?

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New2vtgpc

Experienced Member
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Oct 22, 2019
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122
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Iowa
Ok so earlier i restored an apple ii+ (bell and howell). Resocketed chips, deep clean etc...
I had no drives so I used an audio cable and the Apple disk server to play some games...but only a few games worked (me pacman, space invaders)
All other gave errors (garbage on screen). After getting a drive and controller card, I tried making the diag floppy but kept getting checksum errors, I finally got a floppy to format and it copued some data but them errored out...but when ibtried to read it back, a cap blew on the 16k add in card.
Could that faulty cap been the issue? I know caps are cheap, but I dont want to waste time fully recapping this card and have it still be junk when i can try and find a different one and hope for a working card...
So am I on the right track of this 16k card being just a bad cap? Or could my issues be more?
 
Most of the caps on a 16 K card are decoupling ones so I don't think this is an issue. But you don't provide many detail about the card : what model is it ? There are tons of card. A picture would help.
Anyway, you can try to test the base 48 K RAM using this method :
1. Go to the monitor (CALL -151)
2. Type in the following code (don't forget the space between 34:14 and Return).
C050 C053 C054 C057 N 265:FF N 266<265.BFFEM 266<265.BFFEV 265:0 N 266<265.BFFEM 266<265.BFFEV 34:14 (Return)

The Apple II will go to HGR mode and display white and dark graphic screen along with question marks and inverse @ characters at the bottom of the screen.
If some RAM chips are bad, faulty addresses will be printed on the bottom of the screen.
 
Last edited:
trash_44fr said:
Most of the caps on a 16 K card are decoupling ones so I don't think this is an issue. But you don't provide many detail about the card : what model is it ? There are tons of card. A picture would help.
Anyway, you can try to test the base 48 K RAM using this method :
1. Go to the monitor (CALL -151)
2. Type in the following code (don't forget the space between 34:14 and Return).
C050 C053 C054 C057 N 265:FF N 266<265.BFFEM 266<265.BFFEV 265:0 N 266<265.BFFEM 266<265.BFFEV 34:14 (Return)

The Apple II will go to HGR mode and display white and dark graphic screen along with question marks and inverse @ characters at the bottom of the screen.
If some RAM chips are bad, faulty addresses will be printed on the bottom of the screen.
Click to expand...

I wondered about the cap thing. It was just odd it popped one while trying to read a floppy,. The machine came from a school and had a sticky note saying "bad card" but only had the 16k card. As for the model its just a generic 16k, not language or Microsoft branded like most.
Can I test the fist 48k with the card out? Theres a socket for a ram chip, but the only spare I have causes some faint lines on screen when I use it
 
OK, so it seems you have a bad RAM chip on row D, probably the one located at D7. You can try to swap two chips, D7 and D10 for exemple. In this case, the error should be xxxx-FF (7F).
You have to replace the bad chip. The test won't print any error with workings RAM chips.
 
trash_44fr said:
Most of the caps on a 16 K card are decoupling ones so I don't think this is an issue. But you don't provide many detail about the card : what model is it ? There are tons of card. A picture would help.
Anyway, you can try to test the base 48 K RAM using this method :
1. Go to the monitor (CALL -151)
2. Type in the following code (don't forget the space between 34:14 and Return).
C050 C053 C054 C057 N 265:FF N 266<265.BFFEM 266<265.BFFEV 265:0 N 266<265.BFFEM 266<265.BFFEV 34:14 (Return)

The Apple II will go to HGR mode and display white and dark graphic screen along with question marks and inverse @ characters at the bottom of the screen.
If some RAM chips are bad, faulty addresses will be printed on the bottom of the screen.
Click to expand...

Hi I ran this on my Apple ][ Plus and after a while it still shows the inverted @ along the bottom (4 rows). Can I assume I have no bad RAM?
 
Probably ;--) If all the RAM ICs are okay, you should see 4 lines at the bottom of the screen filled alternatively with question marks and inverse @ signs. The test is running forever, unless you missed the space after 34:14, until you stop (reset) the machine.
If a RAM failed the test, there is an output with numbers, something like this :
Code: 
445E-FF (DF)
445F-DF (FF)
4559-FF (DF)
455B-DF (FF)
 
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