| Posted By
Chronos
on 2006-07-30
08:50:07
 |  annoying bug in my commie
hi!
i've a hardware problem with my commodore, when i pressing enter or making whatever which scrolls the screen, a "!" appears at 0f5e. the question is: is it a ted bug, or a memory bug??? i've posted a picture too..
i have another motherboard with the same bug, so if its a memory bug i can swap memory chips, but i want to make it sure...
It is possible to my video cable kills ted?
http://www.kepfeltoltes.hu/060730/annoying_www.kepfeltoltes.hu_.jpg
if anybody has any idea, please post! 
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Posted By
Lacoste
on 2006-07-30
09:57:46
 | Re: annoying bug in my commie
Maybe CsiO drawed it to your TV with a CD marker!
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Posted By
Chronos
on 2006-07-30
11:11:23
| Re: annoying bug in my commie
sure
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Posted By
Csabo
on 2006-07-30
14:28:22
| Re: annoying bug in my commie
My guess would be that it's a memory bug. $20 = space, $21 = exclamation point, just one bit difference. You could try filling that area with capital B letters, if the same position changes to C, then it's probably the memory. But that's just a guess.
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Posted By
JamesC
on 2006-07-30
15:03:25
| Re: annoying bug in my commie
You have an extra bit floating around in video memory. Remove the top of the case and keyboard, and then turn the bottom part upside down over the rubbish bin and shake out the excess bits.
I'm kidding. It's a RAM problem. Unless you want to replace RAM chips, your best bet would be to replace it and save this unit for spare TED/CPU/eproms.
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Posted By
SVS
on 2006-07-31
02:26:14
 | Re: annoying bug in my commie
You should try this:
a) Remove all the socket ICs
b) Reinsert (carefully) ad press them in their own sockets.
This because maybe there is a false (dirt) contact in one pin somewhere. If you're lucky the unplug/plug operations could solve the problem.
Hard blowing inside the empty sockets will help too.
Keep us informed
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Posted By
Chronos
on 2006-07-31
06:00:01
| Re: annoying bug in my commie
so it caused not my video cable??! or my power supply? i have another commie with ram chips so i will replace it soon..
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Posted By
Chronos
on 2007-03-22
16:20:22
| Re: annoying bug in my commie
next episode.. the project was suspended for a while, because i moved to a new house.. so, i badly need a working commie because i want to test bomberman on real "iron" before shipping it to the customers..
today i tried to reinsert the chips in the sockets and with another video cable (originally Video out - RCA) RF out to Coaxial, but it doesn't help.
if i starting the famous word processor, it give me three of the "!"'s
i have 2 another disassembled plus4 units, friday night i will try to mix the components ...
any new idea, advice something? its possible to something with the keyboard? if i good remember, i tried it once with another motherboard and with this keyboard..
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Posted By
TLC
on 2007-03-23
01:41:26
| Re: annoying bug in my commie
Hmmm.... this is a very interesting bug...
But it might well turn out otherwise (ie. not a dram problem). Those generally don't behave like "can be written, but just once, can be read, fail upon any subsequent attempts to write" or what... they're either blown or not, there's no such "sometimes bad, sometimes good" state. As it looks like, the Ram works well when it's written by the reset routine (else, you couldn't see the "Commodore basic..." etc. screen, maybe, it wouldn't even boot up (as some routines are called up by JSRs, a successful reset needs the stack ie. the ram)).
I'd first do a test by loading and running something from disk (something that can be started by Shift+Run/Stop, that is, you don't need to type too much ). If it runs, the drams must be perfect (even if the screen shows garbage occassionally). ...If it won't, you have a pretty weird dram problem, but nevertheless, it's easy to locate the faulty dram chip, as there are 8 drams in the computer, each holding one of 8 bits of 64K. (Desoldering would be a problem, and won't recommend it unless you or someone around you (someone you can ask to do it) is really experienced).
If it's not the drams, I'd check the FPLA, the keyboard circuit (6529B, TED and such) etc... and so on... you can find all schematics at http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/plus4 .
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Posted By
SVS
on 2007-03-23
08:50:07
| Re: annoying bug in my commie
The character "!" is hex value $21, while the character " " (space) is hex value $20. It could be that the word processor sends character space ($20) but the signal arrives as $20+1=$21 caused a bit more.
The dirty bit could be added by a fault of a hardware fault.
You should have to check the ICs of your machine.
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Posted By
Chronos
on 2007-03-23
18:33:09
| Re: annoying bug in my commie
a special thought about the keyboard of the plus4: its a f**ing piece of sh*t, especially the contacts, and the connector to the mainboard.. its an industrial junk! any idea to repair the connector .. the small metal stripes peel off from the plastic junk.. aaa, the c16 and c64 has great keyboard, the guy who engineered this one was a retarded monkey..
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Posted By
Chicken
on 2007-03-24
09:21:43
 | Re: annoying bug in my commie
Honestly, I like the plus/4 keyboard much better... if it's working  It's a "love or hate" thing, I guess. I remember watching APOS literally hacking his C16 keyboard... I could never type like that :D
Cleaning the key contacts and adjusting some springs usually helps a lot. On a friend's keyboard connector the metal contacts peeled off, too. We carefully glued them back to the plastic with superglue/instant adhesive. Do not apply the glue directly to the plastic. Make a small spatula from cardboard...
Gotta love inet :D Scroll a bit down to see what I mean...
http://cp.c-ij.com/english/3D-papercraft/help/tips.html
Just use LESS glue A single drop will do...
And make sure the glue is completely dry before you plug in the keyboard connector.
Or are the metal foil contacts completely ripped/broken off?
Maybe we should collect hardware maintenance hints and add them to the trouble-shooting section of the encyclopedia because I think these questions will come up again and then it's easier to find them.
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Posted By
Chronos
on 2007-03-24
14:46:50
| Re: annoying bug in my commie
lastly all my pain gone i tried to use csio's motherboard with this working keyboard and whoala i have a working machine. later i tried my synergy sid card, my 1541-2 with some programs loaded from a floppy disk and everything is fine! i carefully inserted the keyboard connector (just 2 contacts peeled off partly) and its ok. i have a quickshot 2 joy too, so the ultimate testbed is ready.. thanks for everyone to helping me!! just one question remains: if i have an X1541 cable, can i use it under Win XP? i used it 10 years ago..
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Posted By
Chicken
on 2007-03-24
15:06:40
| Re: annoying bug in my commie
Good news
Most sources say, the X1541 cable doesn't work with WinXP. However, somebody (ie Luca ) told me, that his X1541 cable works just fine.
I guess giving it a try won't hurt. But don't hit me if it blows up your system
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