Peter's z80.eu site blog
Short Mac SE/30 adventures 
Friday, February 8, 2013, 09:02 AM
Posted by Administrator
I realized that I didn't made anything meaningful with my Apple ][ Europlus, so I decided to exchange it for another vintage computer - an older Macintosh.
My first choice was a Mac SE/30, because this one can handle up to 128MB RAM, and it's capable to run A/UX. But....

A serious flaw of this model (SE/30) is an unreliable firmware ROM module/SIMM.
You can be lucky if you got a moment of a stable working condition, see here:

Unfortunately getting access to the logic board is not too easy. Opening the case would be very easy - except these two upper deep counter-sunk TORX screws:


This is a schematic picture of the place where you can find that ROM SIMM:

But to get the logic board in your hands, you had to follow a strange method of releasing the board itself from the frame. First you have to draw it a bit, but then you have to lift it on one side, to pull it in all - but SCSI, loudspeaker and floppy drive cable are still connected and will keep it in place. Very ugly.


After discovering that no sound is made from this macintosh, and because the ROM module makes often trouble, I decided to bring it back and take a Colour Macintosh (will be described in next blog entry).


Btw.: A good article about repairing a Mac SE/30 can be found at www.biwa.ne.jp
add comment ( 183 views )   |  permalink   |  related link   |   ( 3.1 / 921 )
New toy, an old, autonomous working Eprom Burner, a Needham's SA-20 ... 
Monday, January 21, 2013, 10:30 PM
Posted by Administrator
That was really tricky.
I buyed an old but autonomous working Eprom Burner, a Needham's SA-20 (Wilke Technology), and I hoped to work with it connected to my modern PC (which has a COM1 interface).
Unfortunately only a DOS program exists so far for it (but there is hope, source code of that DOS program is included). So I decided to give it a chance by using VMWare Player with installed Windows 98 SE. I tried also pure DOS mode. But it worked only partly and slow.
It seemed my key strokes were eaten somewhere, or another reason exists for a painful slow remote PC control via serial interface (115K baud,N,8,1 - that's fast enough usually).
Trying to use it with a Intel 486 driven Siemens Notebook and DOS from Windows 95B worked like a charm. But look at this beauty. It can copy 8 EPROMs at once !

If someone has an explanation for that strange serial interface behaviour, I would really please you to share your knowledge. Serial port setup in VMWare used "host device" mode.

I found also a very helpful site describing made expirience with a parallel port connection, so I tried only using it via serial interface.

See related link below for that article...
add comment ( 183 views )   |  permalink   |  related link   |   ( 3.1 / 5097 )
Commodore Plus 4 resurrected... 
Sunday, January 13, 2013, 01:00 PM
Posted by Administrator
An underestimated beauty, the Commodore Plus 4 (aka 264), was resurrected in two steps:
First I realized that the power supply was dead. Due to the fact, that these power supply cases were glued, not fixed with screws, I did not tried to open it (to repair it).
So I cutted the very rare foursquared power connector, and created an "power connector adapter", also because I did not planned to modify my Plus 4 (exchange the connector inside the computer).


After having the possibility to test it with a C64 power supply, I realized that it was still defective :-(
I got only a black screen at channel 36 (UHF) when powered on. It seemed that the video controller chip 8360, aka TED, was dead (also very rare unfortunately).
So I buyed another Plus 4 on Ebay, also partly not working.
The second one showed the BASIC free message at the beginning, but crashed early after typing in some BASIC commands. This can be related with defective RAM chips (4164).
But it was easier to exchange the working TED video controller, so my first Plus 4 was working again without any problems.
These TED / 8360 chips getting hot, unfortunately the original copper metal plate does not seem to cool it down enough:


A good replacement for this copper plate seems to be that item:


You have to use Thermal Compound for Cooler in the mid, but to fix it, you have to use "super glue" at the edges.
add comment ( 175 views )   |  permalink   |  related link   |   ( 3.1 / 891 )
Strange C64 cartridge "Story Machine" from Spinnaker Software ............ errorneous software selled from beginning? 
Saturday, December 29, 2012, 01:48 PM
Posted by Administrator
I am always looking to complete my cartridge collection for my C64.
Now I've obtained a cartridge named "Story Machine". Regardless of the poor presentation and functionality, I thought it should work as designed, at least you should save your work to disk and load it later again.
This is the cartridge:


And this is the strange result of 4 minutes work with it:


Up to this point, I was not really impressed, but I thought, it's a rare cartridge, so who cares. Then I saved the created "story" to disk and I tried to load it again.
This happens then:


What's that sh*t ?

Tested on VICE 2.22 also, with JiffyDOS Kernal and JiffyDOS C1541 ROM. Does it work better without JiffyDOS ?

Added later: No, it's not related with JiffyDOS. It's related with the cartridge software itself. It's just poor software quality, faulty, the developers never assured all works. See, this happens also:


All errors will appear only, if you save your work and later try to reload it.
If you do not save the story, but don't power off, you will be able to replay it.

Added later:
Strange PCB layout and used ROM chip for this cartridge:


You can grab the cartridge file >here<.
add comment ( 185 views )   |  permalink   |  related link   |   ( 3.2 / 76 )
Apple I auction ended with fantastic price... selled for ~half a million EURO 
Monday, December 10, 2012, 09:00 AM
Posted by Administrator
Almost unbelievable, what some are willed to pay.
An Apple I was auctioned for a price others would buy a house instead.
Original Apple I are very rare, also because only about two hundred devices were selled in 1976. A similarity to the later Apple II is easy to recognize, but only in terms of electronic design/circuits.


But only a few knows a very good replica is offered:
>> Briel Computers Replica 1 <<
You will got the (original) feeling for a fraction of the costs ;-)

Not really easy to explain - original, old MOS Technology KIM-1's are much cheaper, but have almost the same historical meaning.
P.S.: You can get a replica of a KIM-1 at brielcomputers.com too (named Micro-KIM) ...

Added later:
There was a second Apple I replica made, look here for more infos.
Thanks for the comment !

2 comments ( 188 views )   |  permalink   |  related link   |   ( 2.9 / 80 )

<<First <Back | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | Next> Last>>