Gibberish video upon bootup of an early series Apple ii

13 posts / 0 new
Last post
Offline
Last seen: 1 week 1 hour ago
Joined: Aug 27 2018 - 03:13
Posts: 5
Gibberish video upon bootup of an early series Apple ii

What could be wrong with my Apple ii? When I turn it on, I only see gibberish video output. No speaker beep sound.

Am not sure if 1) am not using the right display - just attached it to a video grabber USB dongle. 2) my keyboard is not working hence the reset signal is not being sent to the computer for it to boot properly. 3) something else is wrong.

I had already replaced the power supply with a new one from Reactive Micro.

1978AppleII's picture
Offline
Last seen: 1 week 1 hour ago
Joined: Jul 5 2015 - 16:54
Posts: 208
Depends...

Depends on the exact Rev of the motherboard.

If it is a Rev 0 motherboard and still has the original Integer ROMs, it is normal for them to boot to gibberish - you just need to press the RESET key to get it to a prompt.

If its a later revision of the motherboard, could be lots of possible causes. Can you post a pic of what you are seeing on the screen?

Jennifer

Offline
Last seen: 1 week 1 hour ago
Joined: Aug 27 2018 - 03:13
Posts: 5
Rev 0

Ebay item
It's actually on auction now but you can see pictures of the computer here. If I don't get to sell it, maybe I should give it one more go to try to fix it.
I think my keyboard has a problem and it is not recognizing the reset signal. How do I check if keyboard is functioning?

Offline
Last seen: 1 hour 45 min ago
Joined: Aug 4 2018 - 21:59
Posts: 48
piedad wrote:Ebay item

piedad wrote:
Ebay item
It's actually on auction now but you can see pictures of the computer here. If I don't get to sell it, maybe I should give it one more go to try to fix it.
I think my keyboard has a problem and it is not recognizing the reset signal. How do I check if keyboard is functioning?

It wont be the keyboard, the motherboard has its own power on reset circuit. The symptom you describe can be caused by almost every chip on the board. It could be a faulty chip or a bad socket and on boards that old it might even be a fractured trace but that is less likely.

Offline
Last seen: 1 day 16 hours ago
Joined: May 24 2016 - 11:49
Posts: 14
Screenshot?

Did you have a chance to post a screenshot picture?

1978AppleII's picture
Offline
Last seen: 1 week 1 hour ago
Joined: Jul 5 2015 - 16:54
Posts: 208
Info

Yeah, it could be a number of different chips. Btw your eBay listing says its a Rev 3 motherboard, however if the 4 digit serial number written on the left rear corner is correct this should be a Rev 0 board. There were 2 iterations to the Rev 0 motherboards, the first 3000 or so had light green slots, the later 3000 or so had darker green slots which yours appears to have.

If you carefully remove the CPU chip and look beneath it - it will confirm once and for all what Rev motherboard you have.

Alternately if you look beneath the keyboard on the right hand side of the motherboard, you should see a large prototyping area on the motherboard if this is a Rev 0 - which isn't present on any other Rev motherboards.

Unfortunately in this condition my guess is you are looking at between $2000 and $4000 (tops) in this condition. You would almost certainly get more if you could get it fully working.

Jennifer

1978AppleII's picture
Offline
Last seen: 1 week 1 hour ago
Joined: Jul 5 2015 - 16:54
Posts: 208
Prototyping Area Pics

If you visit this site, the very first pictures are of the Rev 0 motherboards...

Apple II Rev 0 Motherboard

If you look along the bottom most row of chips, the large "open" prototyping area can be seen on the bottom right hand side of the motherboard. Later motherboards had a much smaller area.

Jennifer

Offline
Last seen: 1 day 16 hours ago
Joined: May 24 2016 - 11:49
Posts: 14
Original Rev 0’s

The original Rev 0’s had turquoise edge connector slots...
I was there and have two of them that have been in my possession since they were manufactured...

1978AppleII's picture
Offline
Last seen: 1 week 1 hour ago
Joined: Jul 5 2015 - 16:54
Posts: 208
Sounds about right :-)

AppleEmp393 wrote:
The original Rev 0’s had turquoise edge connector slots...
I was there and have two of them that have been in my possession since they were manufactured...

Yeah sorry, that's just how I describe them. (I am also slightly color blind) Smile

I have 1 early Apple II, A2S1-1491 which has those lighter color expansion slots.

Can you confirm when abouts they changed to the darker color slots? I think from the ones I've seen that its around the 3000 mark.

Jennifer

Offline
Last seen: 1 week 1 hour ago
Joined: Aug 27 2018 - 03:13
Posts: 5
Full details finally online

I finally found the time to take high-resolution photos and a video. You can read about this machine here: My Vintage Apple II.

Offline
Last seen: 1 week 1 hour ago
Joined: Aug 27 2018 - 03:13
Posts: 5
No number under the board

Please see pictures in my blog... I don't see any number on the board under the CPU chip. Why?

Offline
Last seen: 1 week 1 hour ago
Joined: Aug 27 2018 - 03:13
Posts: 5
Photos
1978AppleII's picture
Offline
Last seen: 1 week 1 hour ago
Joined: Jul 5 2015 - 16:54
Posts: 208
Number under CPU

I believe that the Rev 0 motherboards didn't have a number - only the later iterations.

Jennifer

Log in or register to post comments