800xl won't go into self test mode

[Retrocactus]

I've had this 800xl in my garage for well over a decade. It appears to work fine (I'm using a newly made USB power supply cable and composite out cable) with my carts, Fujinet, etc. But I can't get it into self test mode to see if anything has gone bad. Holding OPTION down at boot (Fujinet not connected) just seems to freeze things on the blue screen with a cursor. 

 

Any tips to get it to work or alternate testing apps I can load to do it via Fujinet? Or should I just not worry about it since everything else appears to be working just fine?

 

It appears to be a Rev B (Peek 43234 returned 96) and is NTSC (I'm in Canada)

[reifsnyderb]

It sounds like the Option key is being detected.  I'd try re-seating the MMU (U3) and the PIA (U23) first.

Edited July 28, 2023 by reifsnyderb

[+David_P]

In BASIC, try this program:

 

10 PRINT PEEK(53279):GOTO 10

 

RUN

 

Check that the number is changing depending on which console key (START, SELECT OPTION) is being pressed.

 

[Retrocactus]

I should mention that the Option key definitely works…it’s needed for Fujinet to boot disk images and works just fine. 

[+kheller2]

Have you booted to basic and typed bye or dos?

[Retrocactus]

Just now, kheller2 said:

Have you booted to basic and typed bye or dos?

Yes. BYE doesn’t do anything. 

[reifsnyderb]

1 hour ago, Retrocactus said:

Yes. BYE doesn’t do anything. 

If the MMU or PIA isn't working properly, BYE may not work.  I'd re-seat those chips first and see if it changes anything.  If it doesn't, a PIA can easily be obtained and an MMU can either be obtained or programmed.