putting a second internal floppydrive in the STF..

[simbo]

all these lines are buffered so dont worry its still an ident issue


we can safly assume that pin 5 issues arent a problem

so i think pin 10 and pin 12 is all thats needed

and change back the drive b ident to 0

[ijor]

Can you read whole disks with both drives? (to verify that seeking is working correctly).

I suppose you are using DD disks and NOT HD ones? (if using HD disks, you should at least cover the second hole).

Do you have disks that you can read with a PC (or another ST)? If so, after attempting to format and writing on the ST, put them back on the PC. Can you read them as nothing happened to them? If so, you have a problem related to the WG signal.

It’s very unlikely you fried the FDC.

[Lando_C]

Both drives are strapped as factory, i'e drive 1/B.

But the twist in the cable makes this irrelevant, the only need is for both dirves to be strapped alike, and they are.

I am going to resolder the wires in the pbc holes tomorrow, maybe i got a cold solder somewhere (write data or write gate).

Would writing take more power than reading?

The screen (SM125) darkened slightly at floppy motor start when both drives are connected. I changed PSU and this went away, but still the same problem. I do think the old PSU is marginal, all the same.

[Lando_C]

known good disks that I tryto write to on the 1040 (in any drive) DO get garbled FAT and is unreadable on the 520 after that. they can be reformatted on the 520, so are not physically dmaaged.

the 1040 CAN read entire disks correctly (FastcopyIII scans disks without errors), auto progs load from A drive correctly, i can read files at will. (until i try to write to a disk, then it's fried, as I say.)

Would it help you if i run a sector editor on the 520 and look at the FAT to verify if its zeroed or garbage data on it?

[simbo]

yes possible cable problems
man you should use a socket and solder it in perminant

then use a fresh cable with twist

yes however are you using pin 10 and 12

and 14 or just 10 and 12

at the moment

[Lando_C]

right now, it connected like this:

cable 10 and 16 to hole 16 (motor on for both drives)
cable 12 to hole 10 (drivesel A)
cable 14 to hole 5 external (drivesel B)

[Lando_C]

wirie data lead was cold soldered, came out when i pulled on the cable.

I'll have to get a floppy cable with multistrand wires, these single strand wires are not good for soldering in the pcb holes.. theyre too thin.

Will be back with new results tomorrow, if i get hold of another cable to try.
now it's sleepytime, it's 1.05 AM

thanks for all assistance so far!

[simbo]

hum

i dont think your connection is correct

however cya soon
sleep well

[simbo]

here is a doc in german as your in sweden i am shure youll be fluent

take a read its short but maybe some german words i dont get there meaning


ATARI exrernal socket<> internal BUS
-----------------------------------------------
1-read data....................2-head load
2-head-select.................4-nc
3-masse........................6-drive sel 3
4-index.........................8-index
5-drive sel 0................10-drive sel 0
6-drive sel 1......6 or 5..12-drive sel 1 {connects to pin 6 revc or pin5 revd
7-masse......................14-drive sel 2
8-motor on..................16-motor on
9-dir select..................18-direction sel
10-step.......................20-step
11-write data...............22-write data
12-write gate...............24-write gate
13-track 0...................26-track 0
14-write prot...............28-write prot.
..................................30-head select
..................................34-ready
...............................1-33-masse


you can test quickly which one
if pin 5 in the socket connects to ground

connect a wire between pin 12 floppy socket and pin 6
if not connect to pin5

this also explains why some external drives missbehave on some stf /fm machines

[ijor]

Would it help you if i run a sector editor on the 520 and look at the FAT to verify if its zeroed or garbage data on it?

It doesn't matter if its zeroed or if it has garbage. If the problem is in the WD signal, then sectors written should become unreadable, or you should get a CRC error in the best case.

If the content of any sector is changed, but yet the sector status is good, then the problem is at some stage before the FDC.

[Lando_C]

Simbo, "masse" means ground. That doc is wrong, becuse in the rev D STF the drive sel B is on pin 5, not 6, since the external socket cannot be drive A, but an external drive is strapped for drive A (atari standard) from factory, just as Ijor said before.

Today I took away the entire cable, cleaned up the PCB and sucked out all old solder i
could get, then resoldered with a fresh multistrand wire flatcable (so the wires dont break
when you wiggle them).

It works!

so, to make a conclusion:

cable 10 and 16 (both motor on) goes to hole 16
cable 12 goes to external drive socket hole 5 (or to L25 on the bridge bank (in my ST, different numbering on different revisions mobo)) (drive sel B)
cable 14 goes to hole 10 (drive sel A)

this will make the last drive (after the kink) on a modern standard PC floppy cable drive A
and the other drive B, if both drives are strapped as drive B (as most are from factory).

[Lando_C]

Now, i have read that you need ot make sure your drives have a "media change" signal that tells the ST when you have switched disks. How can I test if this works or not?

[Lando_C]

great, you could put this in your FAQ, Simbo!

Hmm.. so if I change disks the directory should be re-read and the window updated automagically? Then I havent got this working right.. I am used to having to press "esc" after changing disks. Is this a floppy protocol thing, or should there be an extra wire somewhere?

Could it even be on one of the odd pins?!

[simbo]

no this is the correct behaviour
one way to test it is to use a two disk game etc
and see if it detects disk 2 placed in

however i am shure it still needs the return key {and press any key... etc}

not shure but esc sound right

or click the window corner

i think if its reading and writing this part is working

the true test is copy one to the other and back again

[ijor]

Now, i have read that you need ot make sure your drives have a "media change" signal that tells the ST when you have switched disks. How can I test if this works or not?

Every PC HD drive has the media change signal, but it doesn’t matter here. The ST has no hardware support whatsoever for media change detection.

[simbo]

as per modern disk drive needs for signals

the standard older drives uses is bad

here is a defacto updated standards for the ide connection


change the internal header for a socket {look in the faq's in forum}

get a floppy cable

cut wire 10 join to wire 16 on the cable {leave wire 16 in place}

under pcb join as below

as for REV A and B i think you need to test pin 5 of the floppy external socket

for ground also pin 6
if no ground on pin 5 then pin 5 is the one

if ground on pin 5 pin 6 is the one

FOR STE JUST CONNECT 10 TO 14

AND ADJUST THE CABLE AS PER

adding the high density mod is a good idea also

for this just a logic chip and a xtal is needed

provided your machine has a wd1772 not not a 1770
if you have a 1770 change it for a 1772 - 02


you can test pin 5 and pin 6 external floppy port
to pin 10 and pin 12 on the st {not falcon or others above stfm}
using a diode check for zero ohms

then you can see where to connect what pin 10 to floppy pin 5 or 6

[ijor]

Simbo,

I know some people are interested in the "reverse" mod (sort to speak). They have their internal drive damaged, and then they want their external drive to appear as drive A.

This should be a simpler mod. Just somehow bring the drive sel 0 signal to the external floppy connector pin 5.

So may be you could post some instructions/diagram for this.

[simbo]

Simbo,

I know some people are interested in the "reverse" mod (sort to speak). They have their internal drive damaged, and then they want their external drive to appear as drive A.

This should be a simpler mod. Just somehow bring the drive sel 0 signal to the external floppy connector pin 5.

So may be you could post some instructions/diagram for this.

the external drive select comes from link w2 on some machines

or link w301 w302 in ste {look at the schematics }

or swap connection wire
{the pad pin 6 in stf rev c i have has a wire on the back print
you can cut this track

better if they have the jumper

but its just drive select thats different

try to find what machine it is


if you use pin 6 cut the track to it

and connect a wire from pin 10 of the floppy port {underside the pcb}

to this now disconnected pin 6

this will make the external drive is disk A now


here is a graphic


HOWEVER !!!


in rev d machines {no ground on pin 5 external socket }
all you need do is change the drive id inside the external floppy

[Lando_C]

here is how it looks at last:

http://www.update.uu.se/~ronny/ataridoubledrive.jpg