Logical problem with Apple II europlus error and random freeze

have you checked the RAM?

Looks like a RAM issue to me.

Have you tried the power-on-self-test to see if you get any memory faults?

Hey AppleWoz,

Yes you can run with just the first bank of 16. In fact, while you diagnose things, it's recommended to run just 16k at a time as it's a lot faster to isolate.

When I was diagnosing my own Apple II europlus, this little machine code routine was my life saver. It allowed me to test my RAM and I was able to find the problem.

(It wasn't the RAM on the main board. It was on the 16k Language card)

https://www.applefritter.com/comment/61119#comment-61119

Hope this helps you too!

PS. One of the big problems I had with the europlus was how corroded all the pins and sockets were. I ended up cleaning all of the chips (Following ESD precautions)  carefully, applied deoxit to all the sockets and got it working!

Chesh

Could be many different things. First off, are all of the pictures you posted taken after the machine was first turned on AFTER BEING OFF FOR AT LEAST ONE MINUTE? If not, that could cause what you are seeing.

The other issue I see is that you are crashing into the monitor at locations in the F0 ROM. That could also be at fault. Please post screen shots after going into the monitor and typing F120L F150L <return>. Or after it crashes whatever address is displayed (minus 5-10 bytes).

If you can't type after the asterisk prompt, then the previous commands I suggested won't work. It's possible the F8 ROM is also not working. Assumnig you've already tried removing and re-inserting every chip (especially all of the ROMs) then I'd suggest one of the following approaches:

1. Use a scope or logic probe to test all of the CPU, data bus, address bus, and memory circuits.

2. Get a board that has a dead RAM test utility such as the MultiROM or ROMX. Both of these will also replace the ROMs with a known good image. This can run even if the RAM, ROM, keyboard, display, and I/O circuits are not working,

Hope that helps.

Have you tried just flexing the motherboard and reseating the ROMs to see if anything changes? If it does, you have a bad socket connection somewhere.

So like others have suggested RAM is a prime suspect but I'm gonna take a slightly different path...

First do you have a multimeter? Have you checked the voltages? With a IIe you should be able to test the supply without the main board connected. This is a good first step. Voltages should match the values printed on he supply (at least the US supplies always had the pinout voltages printed on the supply case).

If the supply voltages test fine, remove all cards from the system. I know this doesn't help with loading disks, but we're starting simple and working out...

What happens when powering up with no cards connected (this includes no disk controller nor memory expansion)?

Do you break to the basic prompt? That's the ] If not system does not go directly to the basic prompt you may need to ctrl-reset to break out.

In either case, you should not end up in the monitor (the monitor is the * prompt) 

If you land in the monitor (the * prompt) skip below to Monitor Crash

If you're good at probing a live system may be worth checking voltage on the main board. If you're not trained in how to do this safely don't do this.

Try the built in self test, either right-apple key when power on or both apple keys when powering on. I can't remember which is right for the euro-iie.

If you've run the self test and got the Kernel OK message it's time to dig deeper...  you can try adding a card at a time back in (when unpowered of course!) 

Monitor Crash

Could still be RAM, ROM or anything else.

Try the monitor memory test to check the lower 48K of memory... this is a litle difficult but follow exactly as described and when you see a <KEY> it means to press that key not type it out, so <SPACE> means press the space bar, <RETURN> is the return key.

If you're at a basic prompt ']'enter:

] CALL -151<RETURN>

At the monitor prompt enter:

] C050 C053 C054 C057 N 265:0 N 266<265:BFFEM 266<265:BFFEV 265:FF N 266<265:BFFEM 266<265:BFFEV 34:14<SPACE><RETURN>

The screen should clear black then white and repeat until you reset but the bottom 4 lines are text so they will alternate with the black/white change. If there is an error the system will beep and an address will be printed at the bottom of the screen this will identify where the first RAM problem exists. This is still a first few steps in a long process... will wait to hear how things pan out.

After typing all that  I noticed the other Jeff has been involved... I'll post anyway. =)

AppleWoz wrote:

 managed to give the command call -151 and it gives me this

Whoops, I jus tnoticed a typo in my previous message, I incorrectly had a BASIC prompt  instead of the monitor prompt. I copied the call -151 line for the formatting, but forgot to update the prompt!

Sorry, I know that was confusing. The astrick is the monitor prompt and that's where you should enter this as shown to run the memory test:

C050 C053 C054 C057 N 265:0 N 266<265:BFFEM 266<265:BFFEV 265:FF N 266<265:BFFEM 266<265:BFFEV 34:14<SPACE><RETURN>

Jeffmazur is right, this is a ROM-related fault -- not RAM.  The printed messages depicted in IMG_5137 and IMG_5133 indicate that the CPU executed a bad byte from the F0 ROM, but that doesn't necessarily mean the ROM chip itself is bad.

Most likely, there's a faulty 74LS138 at motherboard location F12 activating more than one ROM at the same time.  Several photos suggest bus conflicts caused by activating multiple ROMs at the same time -- and two of those photos suggest a specific conflict between the E0 and F0 ROMs.  (eg: the second photo in comment #10)

Inexpensive test:

There are four 74LS138 chips in the US Apple II, so the Europlus is undoubtedly similar.  The evidence suggests the chip at F12 is bad, but you might be able to "borrow" one of the other ones as a test:

• H2 - expansion slot device selection (not required if all slots are empty)
• H12 - expansion slot ROM selection (not required if all slots are empty)
• F12 - motherboard ROM selection
• F13 - motherboard IO

Make sure the expansion slots are empty, then try borrowing a 74LS138 from location H12 or H2 to replace the suspicious one at F12.  If that enables you to start the computer and use BASIC, then the original 74LS138 was faulty and needs to be replaced.

jeff d wrote:

Try the monitor memory test to check the lower 48K of memory... this is a litle difficult but follow exactly as described and when you see a <KEY> it means to press that key not type it out, so <SPACE> means press the space bar, <RETURN> is the return key.

If you're at a basic prompt ']'enter:

] CALL -151<RETURN>

 

At the monitor prompt enter:

] C050 C053 C054 C057 N 265:0 N 266<265:BFFEM 266<265:BFFEV 265:FF N 266<265:BFFEM 266<265:BFFEV 34:14<SPACE><RETURN>

I also decided to try the memory of mine.Thanks for sharing

Comprobando la memoria

tulack wrote:

I also decided to try the memory of mine.Thanks for sharing

That's exactly what should happen with good RAM! Clear black (0) then white (FF) and repeat until there's an error or user resets/powers off. This baiscally tests for stuck bits, could use other values like AA/55 or even A5/5A for fun with other charactes/colors. 

Please tell me more about the board! Thought it was a Europlus, but it doesn't look like one.  So many things missing like the slots and ROMs or maybe that's a ROMX installed ot the right? 

I really don't know what I'm looking at here. lol

Oh wait, you're not the OP... is that a II clone board? 

It is definitely a clone board.  It looks like it was probably made from Mike Willegal's Rev0 gerbers with the Logan Greer added Trademark violations (Apple logo).  It's using a substitute for the ROMs and the CHARGEN ROM also.  I don't see any bodges to fix Rev0 bugs,byt they may be done on the back side of the board.  Also note that they used a different power supply connector than Apple.  I don't know why people start with Rev0 boards, they have a lot of problems like video syncing, etc., and limitations like only 4 colors in Hi-Res.  Starting with something at least Rev 7 if not one of the later RFI boards or sone of the clone designs like Unitron would really be better in a lot of ways.  Some of the clone designs integrate useful things like the 16k RAM card, direct EPROM support and sometimes larger density EPROMs like 2732 or even 2764.

softwarejanitor wrote:

It is definitely a clone board.  It looks like it was probably made from Mike Willegal's Rev0 gerbers with the Logan Greer added Trademark violations (Apple logo). 

 

Yes 

softwarejanitor wrote:

It's using a substitute for the ROMs and the CHARGEN ROM also.

Yes

softwarejanitor wrote:

I don't see any bodges to fix Rev0 bugs,byt they may be done on the back side of the board.

I didn't know about all those errors.  It was a personal challenge.  I've never done anything like this before.  She didn't have any knowledge of electronics.

https://www.applefritter.com/content/construction-my-apple-ii-rev-0-replica