Booting A1200 from Zip/Jazz drive possible??

[MarkAshley]

If you are a confident solderer, then the buffered version will be easy. When you go to RS get the components for the buffered version, and also a 14 pin DIL socket for the 7407 IC (so you don't have to solder it directly and risk damaging it). You will also need some veroboard (copper stripboard) and I can easily convert the wiring diagram from ppazip in to a stripboard layout including the correct pins to connect to the 7407.

If however you are not confident to do this, go for the unbuffered version as it does not require any components or striboard soldering, it's just soldering wires to connectors.

[Amiduffer]

Man, I really scammed out on some parts at Weird Stuff Warehouse in Sunnyvale. It's geek heaven. If you're in Silicon Valley, it's worth a visit, I even saw a A2000/Toaster for sale there once. Now I just need to go find the buffer chip and capacitor.

Now a have a few other questions about the schematic.

from Par18-25-------------18-25Zip right below, both the capacitor and buffer chip are connected from Par14, my question is, do you have to connect the Cap. & Chip to each of the wires 18-25

and
 
Par     5  6      Zip
11-----|>-------16
Par     3  4
12-----|>-------1
Par     1  2
13-----|>-------17

Joy     9  8
6 -----|>-------14

what do the right pointing triangles symbolize and the purpose of the numbers to the left and right above them. That's about it. Thanks for your time.

Amiduffer

[MarkAshley]

Have a look at this:

http://www.hardwarebook.net/connector/parallel/parallelamiga.html

As you can see 18-25 are ALL grounds. If I remember correctly, you don't need to connect them all. Try it with only one connected and see if it works.

If the adapter doesn't work then you may need to connect all of them. Jusdging by the diagram they are all connected in parallel to the capacitor and pin 7 of the 7407 IC. However, I really don't think this is necessary.\

EDIT:

I've just rethought this, and there are 8 data pins (2-9) and 8 ground pins (18-25). This makes me think they are all required to be connected, otherwise it will be unable to transmit on any of the data lines that do not have a corresponding ground. Since they are shown as connected in the circuit diagram, you should connect them.

I don't know what the triangular symbols mean on the circuit diagram. They look like logic gates, and the fact that they have numbers next to them suggests to me that they are meant to connect to the 7407. You may want to check with the author before building the device, assuming he is still contactable.

EDIT:

I have just confirmed that thos triangular symbols are transistors within the 7407 IC. So just connect it to the pins as shown in the diagram.

[Amiduffer]

Ok, thanks for all this help. This shouldn't be so bad once I can actually get some time to GET the materials and put them together. :inquisitive: It looks like a fun project.

I hope I can borrow my friends digital camera so I can post a picture of the final product.

[hppacito]

SOrry to interfere, but this can be useful.

The 7407 is an open collector buffer, so to make it work you will need a 1k resistor connected between the output and +5V (this resistor is named pull-up resistor).

Maybe will be better to use a 74244 or 74245 because they can drive more lines ( per package.

Hope it helps and is not redundant/off topic :-)

[MarkAshley]

Thanks for the info hppacito. I wonder why this is not in the original schematic? Maybe it's taken care of by the Parallel port's circuitry? I would suggest building it as designed, and if it doesn't work then try using the pullup resister.

[Amiduffer]

The treasure hunt was partially successfull! :banana:

I located:

Jumper Box
D25 plug
D25 socket
D9 plug
1uF capacitator

None of the Radio Sacks in Oakland had buffer chips or DIL sockets. A couple of electronic stores in Berkeley were recomended, and hopefully, I'll be able to be able to spend a little time up there. Wish me luck. :-)

[MarkAshley]

Why not try the unbuffered version first?

[Amiduffer]

Hmmmm :inquisitive:

I think it'll be the mess of unsoldering everything if the unbuffered doesn't work. :-D

Better safe then sorry. Hmmm?

[AmigaHeretic]

I made and used several of the unbuffered version back in the day.  Used them mostly on my A1200, but also CD32, A500, and A2000.  Never had any problems with the unbuffered version and never noticed any difference with the buffered version.

  I also made a boot floppy that only had a few files on it and it initially assigned everything to the Zip disk and then took off from there. ie  assign c: Zip:c etc. then when loadwb was called it loaded from the Zip.

   Basically did the same thing you want to, using a parallel port Zip drive as a hard drive. Just had to have the floppy in the drive initally is all.  Ah, the good old days :-)

[Amiduffer]

amigaguy wrote:
I made and used several of the unbuffered version back in the day.  Used them mostly on my A1200, but also CD32, A500, and A2000.  Never had any problems with the unbuffered version and never noticed any difference with the buffered version.

 Ah, the good old days :-)

Well, I'm looking forward to better days too. :-D

Ok, Mark suggested I go with a buffered version, and I had a hankering to try my hand at putting something together from scratch, so to speak. Especially, a project that's a little more complicated than soldering a wire together. I have all the componants I need to make an unbuffered connector, so that will be my project for Sunday, if I can't get the time during the week. :hammer:

[MarkAshley]

Good luck Amiduffer. Let us know how you get on!  :-)

[hppacito]

Don't forget to double check the circuit, just to be sure that all connections are were they should be. Brw, don't overheat the IC, better use sockets for them.

[Amiduffer]

Well....

my first attempt, would best be described as, ummm

messy. :roll: :oops:

It's like using muscles you haven't used in awhile. I haven't soldered in years!! But, I quickly caught on.

The current connectors aren't usable, but, luckily, I found this old electronic store in Berkeley (been around since the 50's) and got some 25pin male/female connectors for a couple of bucks. So, I'll try again tonight. :hammer:

[Amiduffer]

Here's the latest bulletin from the front lines... dit dit ditdit. :-)


[color=0000ff]Attempt #2[/color][/u]

I didn't get much sleep last night, but I got ALL of the straight connections soldered together with no problems. The 2-2, 3-3, etc.
Next is stripping wire in lengths to connect the odd connections since the supplied wire that came with the box isn't long enough.

Then, hooking up the joystick connector. Make sure the wire is the right length!!

Keep your fingers crossed! :-D  :-D  :-D

[Amiduffer]

More wires soldered. All that's left is to solder the 9pin to the wires connected to the main unit and it'll be finished!:nervous:

I'm surprised I didn't burn my fingers :shocked: I had to hold the wires just milimeters from the iron.