Conference hydra::amiga_v1

   "DF1: BAD" is suspicious, since that is a floppy device designation.
    I believe you'll need to change your mountlist entry for the '23
    to something like DH1:. Just a guess ...
    

    I bought a Sony drive (720K IBM compatible drive) and got it to
    work by adding 3 chips for the "change" signal required by all
    Amigas.  I soldered the 3 chips one over the other to make it quite
    compact, but, basicaly it works OK.
    
    If you want the circuit,let me know. I can post it here.
    
    The only requirement is that the RX23 has a switch to detect
    the insert/removal of a floppy.  My Sony had one but I know 
    nothing about the RX23, does it?
    
    The 3 chips are standard SN74xx serie (inverter, flip-flop etc).
    
    Vince,

The Amiga floppy disk interface is incapable of handling HD (2 meg or 1.4 meg
format).  I got a query answered from C/A about this, as I was replacing the
internal 3�" drive in my A1000.  It seems that the bandwidth of the interface
can't hack the action (ie. it isn't fast enough to keep up with the higher data
rate that the HD drives generate).  You can install an HD drive, but you can
only use it in DD mode.  The entire disk interface would have to be redesigned
to be able to handle HD drives, no quick fix here.

As to your diskchange problem.  I'm not familiar with the RX23 in particular,
but I can tell you that several of the 3�" floppy drives that I have seen
(especially the newer generation of DD/HD compatible drives) have a jumper or
DIP switch to enable the sending of the diskchange signal when a disk is
inserted.  If there is no documentation to this effect with the RX23, try to
find a jumper or DIP switch inside the drive.  Changing the DIP or jumper
probably won't do anything dangerous (although I'd write protect my first test
disk), and who knows, you may find that it enables disk-change signalling.

 - Mark Jay Jones

    RE .2
    
    If you could upload that circuit it would be much appreciated.
    
    
    Shaun.
    

    pg 27 of the May 1990 AmigaWorld has an ad from Applied Engineering
    
    AE 3.5 Drive is the first high density external disk drive for the
    Amiga.  It supports both standard 880K and 1.76 MEG 3.5" disks.  Housed
    in a thick, high impact, Amiga-beige ABS case, the drive incorporates
    the finest Sony drive mechanism available.  The AE 3.5 also supports
    1.44 high density MS-DOS disk and features electronic disk ejection. 
    $189.
    
    for info call (214) 241-6060, 9am-11pm, 7 days.
    
    
    The drive looks like an Apple external disk drive, with an eject button
    added (or do they come with that now?).  My suspicion is that they are
    describing what the drive can do, not what it can do when hooked to an
    Amiga.  Know of any Amiga that supports electronic disk ejection?
    
    Or maybe they figured a way past the problem with some sort of
    buffering scheme.
    
    -Dave

    re: .2
    1) The RX23 is a Sony drive, so my hopes are high.
    2) It has three microswitches at the front. One to detect write-enable
    (i.e. located at the write protect hole), one to detect HD media (i.e.
    positioned at the opposite side for the 'extra' hole) and a third one
    which does nothing but detect the presence of a disk.
    
    re: .3
>As to your diskchange problem.  I'm not familiar with the RX23 in particular,
>but I can tell you that several of the 3�" floppy drives that I have seen
>(especially the newer generation of DD/HD compatible drives) have a jumper or
>DIP switch to enable the sending of the diskchange signal when a disk is
>inserted.  If there is no documentation to this effect with the RX23, try to
>find a jumper or DIP switch inside the drive.  Changing the DIP or jumper
>probably won't do anything dangerous (although I'd write protect my first test
>disk), and who knows, you may find that it enables disk-change signalling.
    
    Thanks Mark, this looks like it's worth a try, I'll get my screwdriver
    out tonight.
    
    FWIW, re: the little circuit, I'm trying the RX out by simply replacing
    the Chinon mechanism in my external drive, so all required circuitry
    should be there. Please do post the circuit though as it may come in
    handy for the future...
    
    
    					Alan T.

Since few requested the circuit here it is:

Fist thing first, the following circuit was "largely" inspired
(ok, I admit copied...) by M.Deegener and C.Balzer from a more 
complicated circuit (5 chips) used to make 1.2 meg drive seen 
as a 3�" drive.
Their plan was saying "non commercial disrib granted" on it,
so I don't feel guilty.  Thanks to them.

By the way Christian, there is an error on your drawing since you sent
the output of U5,6 to Index,  it shoud go to change...(bus # 11.)
Errare humanum est.

	 	-------------------------------

I could use Dpaint3 to generate, but I am not too sure how to 
"upload" the IFF pic to the Enet. I've heard of trouble to
upload with VLT if not  a text file? Probably a bad setup in
my VLT though.

So I'll try "writing it down" It is probably faster for me anyway.

(I used wire-wrap wire, gage 30)
Take the switch solder tab (the one toward the back of the drive)
and solder wire "W1".

Take the Sel1 line (pin 21?) of the drive 34 pins connector, and
solder wire "W2". (double check in your Amiga book (prints at the
end) for that pin number.)My paper here doesn't mention it.

Take the +5V power and ground with 2 other wires (solder near the
power connector. (leave the +12V alone!) If you don't know what pin
    is the +5, the Gnd or the +12, forget that project...

And last take the pin 2 of the drive connector and solder a wire
"W3". (pin 2 is the change signal)

Bring all those wire where you want to install your chips.

Take 3 chips U1=SN7474
             U2=SN7400
             U3=SN7416               ______
Bend their legs staight i.e:  -------|    |------, if you didn't buy
surface mount chips.                 ------

Solder all 3 pins  7 together Solder the ground wire to it
Solder all 3 pins 14 together Solder the +5 Volt "   "   "
 Jump U1,2 to +5V also.

Solder "W1" to U3,8 and U2,13 and U2,1.

Solder W2 to U2,12 and U3,1

Solder W3 to U3,6.

Solder U3,9 to U1,3
Solder U2,11 to U3,3
Solder U3,4 to U1,1
Solder U1,6 to U2,5
Solder U3,2 to U2,2
Solder U2,3 to U2,4
Solder U2,6 to U3,5

I guess you may find some room inside the drive where you can "crazy glue"
them. I doesn't make such a bad job if you use "surface mount" chip, but
if you do you may require a very "tiny" solder tip.  Normal chips are
quite bulkier and easyer to work with, but may not fit inside your drive(?).

Have fun, let me know if I made any error in the above text. Although
I double checked...

I know that it is not a "professional" looking job, but what the heck,
it works for me.

Of course I deny any responsability of this circuitry. I bought a 
$40.00 Sony drive at a surplus and had nothing but $40 to lose, so
I tried it and it worked for me.  
Very good quality for $40.00

P.S: I just compared my 720K Sony and our DEC RX23...
One question though, I looked at the RX23 and I can't see any
difference in the module exept jumpers (very small surface
mount 0 ohm resistors) and also the fact that the RX23
do not use the normal power connector.  Anybody knows
where the RX23 get it's power from? Must be some pins on 
the 34 pin cable but how did you guys got it to work on 
the amiga?
The heads have a different part number though.

Vince.
    

    
>mount 0 ohm resistors) and also the fact that the RX23
>do not use the normal power connector.  Anybody knows
>where the RX23 get it's power from? Must be some pins on 
>the 34 pin cable but how did you guys got it to work on 
>the amiga?
    
    The RX23 I have, has exactly the same power connector as the Chinon
    drive I replaced ! I had to put a single twist in both the power and
    the 34 way cables though i.e. the two connectors are mounted
    "underneath" the Chinon board and "on top" of the Sony.
    
    				Alan T.
    

    I assume that there must be many flavour of RX23 then.
    
    I looked at some 30-xxxxx class part number.  What is 
    the RX23 model you refer? It may be fun to have a look
    at that one, and compare with my 720K Sony the jumpers.
    
    Thanks in advance,  Vince.

    
\\\    I looked at some 30-xxxxx class part number.  What is 
\\\    the RX23 model you refer? It may be fun to have a look
\\\    at that one, and compare with my 720K Sony the jumpers.
    
I got the same problem with RX23 on Ami, the part# is RX23-A
Let us know....
Regards.
Luca

    I don't know what the DEC part number will be, but I'll take a note of
    the Sony part numbers off the drive.
    
    I had a real close look at it last night and there are dozens of
    jumpers all over the thing..... some are 'made' (with 0 ohm resistors)
    and some are 'open'. All appear to labeled RJnnn. There are too many to
    use trial and error, as I originally intended, so I must get a hold of
    the specs.
    
    				Alan T.
    

    The RX23 is definitely a Sony and is labeled MFD-17W-5GD
    
    				Alan T.