My Apple1 new fault

12 posts / 0 new
Last post
Offline
Last seen: 1 month 3 weeks ago
Joined: Dec 7 2023 - 07:08
Posts: 25
My Apple1 new fault

After my Apple1 power failure is resolved, now there will be only one@ no /after clearing the screen. Only one letter P plus@

 

 

I also checked that each voltage is normal, and the 40 pin of 6502, the voltage on the pins 34 of 6821 is 5 volts. Short keyboard 1-9 will turn 0V.

 

 

 

DRAM I use

 

 

 

Offline
Last seen: 1 month 3 weeks ago
Joined: Dec 7 2023 - 07:08
Posts: 25
I changed the bad 2504 just

I changed the bad 2504 just now, and the starting screen would be gone after rolling up.

 

Offline
Last seen: 1 month 3 weeks ago
Joined: Dec 7 2023 - 07:08
Posts: 25
The problem of rolling

The problem of rolling upwards was solved, and the loss of the back slope did not appear. Does anyone have related experience? I also checked the solder joints and replaced 6520 and 6502

Offline
Last seen: 1 month 3 weeks ago
Joined: Dec 7 2023 - 07:08
Posts: 25
After executing Clear Screen,

After executing Clear Screen, there will be a@,Automatically input after executing Reset

6502's 40pin will not change to 0V after the REST, and the measurement is 1V

 

 

 

Offline
Last seen: 2 months 1 week ago
Joined: Oct 9 2023 - 14:36
Posts: 12
Can you elaborate a bit more

Can you elaborate a bit more about what you're doing in the video? It sounds like you're pressing buttons in the background.What seems to be happening is that you start up the computer. Clear the screen. Then press reset? And reset keeps generating '\' ?

 

edit:A step by step reproduction of the steps would be very helpful. Action followed by response. As an example:Step 1: Applied power  - Screen came on with @_ repeated.|Step 2: Pressed "Clear screen" - Screen went blank and only a single @ was visible.

Offline
Last seen: 1 month 3 weeks ago
Joined: Dec 7 2023 - 07:08
Posts: 25
Jero32 wrote:Can you
Jero32 wrote:

Can you elaborate a bit more about what you're doing in the video? It sounds like you're pressing buttons in the background.What seems to be happening is that you start up the computer. Clear the screen. Then press reset? And reset keeps generating '\' ?

 

edit:A step by step reproduction of the steps would be very helpful. Action followed by response. As an example

 

1. I started Apple1 and appeared correctly @_.

2. I take a short 12-16pin and execute the clearing, just @

3. I picked up 1-9pin shortly and executed the reset, and it kept appearing\

What is the situation caused by this? Thank you for your answer

 

Online
Last seen: 58 min 46 sec ago
Joined: Feb 27 2021 - 18:59
Posts: 488
So?

Well, what were you expecting to happen?

The Wozmon is very simple (it is only 256 bytes of machine code) and does not display a prompt. The only feedback you get is a

"\

"

When the computer is RESET or the ESCAPE key is struck. This is all in the manual. Have you read it?

Offline
Last seen: 1 month 3 weeks ago
Joined: Dec 7 2023 - 07:08
Posts: 25
robespierre wrote:Well, what
robespierre wrote:

Well, what were you expecting to happen?

The Wozmon is very simple (it is only 256 bytes of machine code) and does not display a prompt. The only feedback you get is a

"\

"

When the computer is RESET or the ESCAPE key is struck. This is all in the manual. Have you read it?

 

Thank you for your answer, I won't appear after resetting it\@ 

 

Offline
Last seen: 1 month 3 weeks ago
Joined: Dec 7 2023 - 07:08
Posts: 25
robespierre wrote:Well, what
robespierre wrote:

Well, what were you expecting to happen?

The Wozmon is very simple (it is only 256 bytes of machine code) and does not display a prompt. The only feedback you get is a

"\

"

When the computer is RESET or the ESCAPE key is struck. This is all in the manual. Have you read it?

After resetting \ will always enter, not 

\

@

 

 

 

Online
Last seen: 58 min 46 sec ago
Joined: Feb 27 2021 - 18:59
Posts: 488
okay

So if the monitor outputs a "\" character, it means the code

FF1AA9 DCESCAPELDA #$DC"\".
FF1C20 EF FF JSR ECHO

Output it.

FFEF2C 12 D0ECHOBIT DSPDA bit (B7) cleared yet?
FFF230 FB BMI ECHONo, wait for display
FFF48D 12 D0 STA DSPOutput character. Sets DA.
FFF760 RTSReturn.

was executed. But instead of running the next instruction after the call at FF1F (GETLINE), the computer looped back to ESCAPE. This probably happened because it got reset again. To call a subroutine and then return, the 6502 needs to read and write to the stack in page $01 (addresses $0100 to $01FF). A fault accessing memory could therefore cause what you're seeing.

Offline
Last seen: 1 month 3 weeks ago
Joined: Dec 7 2023 - 07:08
Posts: 25
robespierre wrote:So if the
robespierre wrote:

So if the monitor outputs a "\" character, it means the code

FF1AA9 DCESCAPELDA #$DC"\".
FF1C20 EF FF JSR ECHO

Output it.

FFEF2C 12 D0ECHOBIT DSPDA bit (B7)

 

 
 
Now after my Apple1 is reset, it will not appear \\\\\\\
Only one will appear in resetting \@ 
 
No like a manual
\@ 
Offline
Last seen: 2 months 1 week ago
Joined: Oct 9 2023 - 14:36
Posts: 12
You should probably try to

You should probably try to stick to one troubleshooting thread.

UncleBernie already pointed out that you probably want to look at the cursor state machine circuitry: https://www.applefritter.com/comment/105880#comment-105880

Log in or register to post comments