From Newsgroup: comp.sys.cbm

On Mon, 30 Jun 2003 23:14:25 +0000, Daniel Karlsson took his/her keyboard and got this out:

Anyway. I have been looking at the schematics a little bit closer now (i.e. actually read it, not just coppied it from the paper to the drive, so to
say) and I have noticed that the parallel part isn't grounded. I have sometimes used the drive whith the C= (i.e. with the serial connection attached: 1541<->C64) while the parallel part still have been connected to the PC whith the PC running. Maby this might be it, what do you think guys?

This IS it. When the c64 is connected trough serial cable to 1541 and pc is connected to parallel port using just 8 wires there is NO grounding between
c64 and PC. In Finland there might be 115 volts between a c64 and a grounded pc. Remember that c64 and 1541-II are floating devices, where PC is grounded. This causes the sensible VIA to break in nanoseconds. There is a cheap ttl
chip on the serial line protecting the VIA, but on parallel line there is no ttl chips as buffer. So the VIA itself is the buffer now, and that causes
your chips to break. The new 65C22 chips those are produced by WDC should be compatible with 6522, but i have not yet tested that on any of my drives (I have some on stock).

And besides this it has never failed while in use and maby this points towards what I talked about before in this posting, with the grounding.
Then the sollution would be to completely disconnect the drive from the PC when using it whith the C=.

Yes. that is the solution. NEVER let the parallel cable connected alone to
1541 and pc WITHOUT the serial portion connected! The serial cable also gives the grounding that prevents the chip fail. When you disconnect cables FIRST remove the parallel cable THEN serial cable. And when connecting FIRST serial cable then PARALLEL cable. I remember from SC times that i might have seen
this kind of advice in SC documents. Nowadays i am using linux, and i am
using only serial portion (i do not want to modify my drives much, although I am enough skilled to that... just do not want to destroy anything)

Regards
/djk

--
Pekka "Pihti" Takala
Nothing can be so bad that you cannot find something good in it!
65XXX assembler programmer/developer, linux user

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From Newsgroup: comp.sys.cbm

Hi Daniel,
you discussed some "drawbacks" of the Commodore "parallel cable"
known from many floppy speeder systems and copy programs and
it's incarnation with Joe Forster XP1541 cable.
Some snippets from the discussion:
Daniel Karlsson wrote:

Joe Forster/STA wrote:

Daniel Karlsson wrote:

I have been using a XEP1541 cable to transfer disks to and
from my C= and I am now in on my 5'th or 6'th drive. The
thing is that this cable seems to eat VIAs for breakfast
or something. [...] I haven't seen any official note on
the SC home page that say that it's any risks in using
this cable

[...]
I believe that 1) your cable, 2) your PC may be faulty or 3) your power
outlet may not be grounded (properly). Just a guess: one of these leads
to more current or higher voltage (?) arriving at the serial port of
the poor drives.

Well I can't use it for now anyway, i.e. not as parallel. I haven't had time to unsolder the faulty VIA in the 1541-II yet. [...]
I've talked to Ed/WD and he says that he talked with you over IRC about this problem for a couple or three years ago. Maby you have forgotten or he is misstaking, but according to him you had said that one actually should use a 10 Ohm resistance over the parallel part to be on the safe side. To me it sounds to be a bit low. If one would use resistance to be on the safe side, why then just use 10 Ohm, but maby it makes sense to you or someone else in this group.

In my personal opinion such resistor won't give a much higher
protection to your VIA or CIA chips against overvoltages. They
may only reduce problems, when the both port chips are fighting
against each other (both ports configured for output, one
driving a High level, the other driving Low). Nicolas Welte
often stated here, that these driver fighting isn't really a
problem with NMOS technology, since they can only drive a high
current with a Low level. The chip driving the High will lose
the fight, but most probably won't damage.
But this all applies to the well known Commodore parallel cables
only, where a CIA (C64) is connected to a VIA (1541).
Whenever an external source is able to drive a High level at a
high current and the VIA fights against it with an output Low,
hmmmmm, may be not so good. But I am not the expert in this.
Since I tested many, many parallel port cards and floppy disk
drives with the Star Commander and never shoot a VIA in all my
different tests, I can only say, that the issue described above
is not really a problem, that damages your drives.

Anyway. I have been looking at the schematics a little bit closer now (i.e. actually read it, not just coppied it from the paper to the drive, so to
say) and I have noticed that the parallel part isn't grounded. I have sometimes used the drive whith the C= (i.e. with the serial connection attached: 1541<->C64) while the parallel part still have been connected to the PC whith the PC running. Maby this might be it, what do you think guys?

Yes, incorrect or missing grounding seems to be more a reason
for your failures. I just shot a VIA, when I removed the serial
cable between my C64 and a 1541 and the 1541 was not switched
off (only the C64 was switched off). Since I let the parallel
cable connected, when I removed the serial one and in combination
let the 1541 switched on, the missing ground connection may have
damaged the VIA.
There exist two important rules, really well known since the old
days:
Alway switch off all the components, when inserting the serial
and/or other plugs into the computer or your drives. The same
applies, when removing cables from your computers or drives.
If all devices are switched off, when doing the cabling, the
missing ground line of the parallel cable doesn't matter,
because the serial cable does the grounding.
You only risk damages, if you switch on one of the connected
devices and the serial cable is not connected.
I wouldn't call this a Star Commander specific problem, since SC
derived these problems in general from the old standards
(Commmodore parallel cable concept).
But improvements could be made nevertheless. I personlly already
use grounded parallel cables since 1986. Roßmöller always used
26pin flat cables, were every 2nd line is conncted to ground.
It's the same principle as with SCSI flat cables and brings up
a better signal shielding despite the fact, that there is an
additional ground connection with the parallel cable itself.
But such high quality made cables are pricey, recently I built
some 40pin VIA adapter sockets (with PCB, a precision pin
header and a precision socket) with 26pin flat cable connectors.
A complete cable (PCBs, sockets and precision pin header,
connectors, Userport connector, 26pin flat cable) costs me
something around 10 to 15 EUR for only the components!
A ready manufactured complete cable will surely cost something
around 50 EUR, if it is more or less professionally made...
Womo
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From Newsgroup: comp.sys.cbm

Hi Daniel,
somehow the quoting became disrupted... I try to repair this.
Daniel wrote:

Womo wrote:

There exist two important rules, really well known since the old
days:
Alway switch off all the components, when inserting the serial
and/or other plugs into the computer or your drives. The same
applies, when removing cables from your computers or drives.

If all devices are switched off, when doing the cabling, the
missing ground line of the parallel cable doesn't matter,
because the serial cable does the grounding.

You only risk damages, if you switch on one of the connected
devices and the serial cable is not connected.

--------------------------------------------------------------
I have never, ever, connected or disconnected anything to or from the computer or drive while they where stil switched on, exept from the NEOS mouse, but your supposed to attach that with the computer switched on. The thing is that I thought that the parallalel part of the connection _was_ grounded, so that it was no danger in: turning of the PC and the drive,> disconnect the serial part from the PC and connect the drive to the C128,
switch on the C128, the drive and the PC. Apparently this was wrong. It has worked to do so some times, sometimes not.

Oh, I see, so only the missing ground is most probably
responsible for the VIA defective.

Of course it isn't. It acctually hasn't anything to do with the SC at all
and it hasn't been my intention to blame anyone at all. My goal is just to solve the problem. But mayby Joe should take this discussion in count and change the design of the parallel part as decribed here:

I think, he will change the design, if we all get a proof
that the additional ground lines don't have other negative
side effects.
It is much more important to switch off the devices then,
that are going to be connected to each other. And good
connectors ensure, that the ground connection is made,
before any other of the pins is connected.

I suppose that it hasn't have to be as complicated as
to ground every signal, as it's not signal interference that is the problem here. Wouldn't just one ground line between the PC and the drive do the> trick? I can say that if I would build something like you suggest I would

If you want to solder the cable into your drive instead
of building a removable adaptor, I would also recommend
to connect the ground line(s) at the 1541 PCB board ground
as proposed. If you want to have a VIA adaptor, you could
use VIA pin 1 (Vss) instead. And yes, a single ground line
should work.
And take into mind, that you are a tester for this "new"
cable concept now :-) I can't guarantee any success,
neither can I guarantee, that you won't shoot some more
VIAs. Perhaps there's another reason for the failures we
all didn't recognize until now.

get ruind :). Here in Sweden just the userportstecker costs 20 EURO with MWS... Wenn man nur nach Deutschland umziehen könnte. Aber wir haben die

In my opinion electronic parts for end users are too
expensive in general. Whenever I think about producing
some C64 hardware stuff for a handful of people I end up
with prices between 50 and 150 EUR, if I take
manufacturing costs and ensurances (2 years warranty and
other) into account...
My full respect goes to Joe and his friends who do a
really great job for this little money.
Womo
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From Newsgroup: comp.sys.cbm

Hi Agemixer,

Ouch. Why in the moon the parallel port has no grounding?

The cable looks like a bomb. Easily fixed...
[...]
If they first made a proper design of this cable, they would have no need
to type in such a bother...

It is very comforting to know that such omniscient individuals are
still frequenting this newsgroup. Perhaps, next time, you might
wanna join us in the development of a new cable if you're so aware
of all possible problems...

You should take into account that all the cables were designed to be
as simple as possible. Just wanted to mention this before you'd visit
the pages of the XP1541 cable and jump on us again, because it lacks
the two handshake lines that are present in the SpeedDOS parallel
cable that it was based upon...

Joe Forster/STA
sta@c64.org
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From Newsgroup: comp.sys.cbm

Hi Daniel,

But mayby Joe should take this discussion in count and
change the design of the parallel part

Agreed. As soon as we discuss this - with Nicolas, Womo and Mr.Axel -,
I'll do what I can about this.

As far as I remember, Mr.Axel had a reason to keep us from using
another GND connection - but I don't remember at all what the reason
exactly was! <:-) - and now Womo is also thinking about the two GND
lines possibly creating a "receiver loop" (whatever that is; I'm
stupid when it comes to electronics... <:-) ).

Joe Forster/STA
sta@c64.org
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From Newsgroup: comp.sys.cbm

Womo wrote:

Daniel wrote:

Hi Daniel,

Hi Wolfgang!

somehow the quoting became disrupted... I try to repair this.

Yes I've noticed that. OE doesn't ad quoting marks when I answer you. Od.
I'll try to compensate...

I suppose that it hasn't have to be as complicated as
to ground every signal, as it's not signal interference that is the

problem

here. Wouldn't just one ground line between the PC and the drive do the
trick? I can say that if I would build something like you suggest I would

If you want to solder the cable into your drive instead
of building a removable adaptor, I would also recommend
to connect the ground line(s) at the 1541 PCB board ground
as proposed. If you want to have a VIA adaptor, you could
use VIA pin 1 (Vss) instead. And yes, a single ground line
should work.
And take into mind, that you are a tester for this "new"
cable concept now :-) I can't guarantee any success,
neither can I guarantee, that you won't shoot some more
VIAs. Perhaps there's another reason for the failures we
all didn't recognize until now.

I won't test it until you have talked it trough anyway and no I would like
to use the fancier "game port on the 1541" solution. It looks much more professional and neat :). Anyway I have already made a hole for the game
port and this is the sollution I have used before so the only change would
be to ad ground to one of the pins of the game port and there are plenty of pins left over (11-15 is unused in the current design).

get ruind :). Here in Sweden just the userportstecker costs 20 EURO with
MWS... Wenn man nur nach Deutschland umziehen könnte. Aber wir haben die

In my opinion electronic parts for end users are too
expensive in general. Whenever I think about producing
some C64 hardware stuff for a handful of people I end up
with prices between 50 and 150 EUR, if I take
manufacturing costs and ensurances (2 years warranty and
other) into account...
My full respect goes to Joe and his friends who do a
really great job for this little money.

I agree in both parts, but it's no doubts about it: Electronic parts are
much cheaper in Germany than in Sweden or, maby, electronic parts are much
more expensive in Sweden than in rest of the "first" world.

Regards
/djk


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From Newsgroup: comp.sys.cbm

"Joe Forster/STA" <sta@c64.org> skrev i meddelandet news:8e5ecfb7.0307020909.170f492e@posting.google.com...

Hi Daniel,

But mayby Joe should take this discussion in count and
change the design of the parallel part

Agreed. As soon as we discuss this - with Nicolas, Womo and Mr.Axel -,
I'll do what I can about this.

As far as I remember, Mr.Axel had a reason to keep us from using
another GND connection - but I don't remember at all what the reason
exactly was! <:-) - and now Womo is also thinking about the two GND
lines possibly creating a "receiver loop" (whatever that is; I'm
stupid when it comes to electronics... <:-) ).

Hi Joe!

I'll wait for the result of your discussion then. I'm not an electrician
ither so it's better to wait until the professionals have talked it through. Stupid of me not to talk with Nicolas directly but I didn't think of that.
If isn't possible to ground the parallel part separetely, maby you should
make note that one never should have the parallel part of the cable
connected to the PC if one disconnect the serial (XE) part, as Pekka Takala stated in another message. I hope that everything is going to work out, as I was going to help Ed and Joe/WD to transfere a couple of hundred disks in
the near future, and the parallel connection realy makes a difference :).

Regards
/djk


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From Newsgroup: comp.sys.cbm

Randy McLaughlin wrote:

In OE 6 select tools->options->send->(news sending format, plain text settings):

Make sure indent the original text with ">" (or what-ever)

95% sure he did this, as most of the time the indenting in his postings
works. I also had a few contacts where Outlook simply refused to do it,
without apparent reason. Daniel, I suggest you check out OE-quotefix, a
_very_ useful freeware add-on for Outlook. That'll put unreliabilities like this to an end.

http://flash.to/oe-quotefix/

(I can't stop slapping my own shoulder every day for installing this!)
;-)

Regards,
Steppe


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From Newsgroup: comp.sys.cbm


Joe Forster/STA wrote ...

It is very comforting to know that such omniscient individuals are
still frequenting this newsgroup. Perhaps, next time, you might
wanna join us in the development of a new cable if you're so aware
of all possible problems...

You should take into account that all the cables were designed to be
as simple as possible. Just wanted to mention this before you'd visit
the pages of the XP1541 cable and jump on us again, because it lacks
the two handshake lines that are present in the SpeedDOS parallel
cable that it was based upon...

Perhaps Agemixer was a little inelegant in his description of the problem.
But he did have a good point. Allowing a "floating ground" condition to
exist is poor design. Not only in computer equipment, but in other
electronic and electrical equipment as well.

In the case of computer and solid state electronic equipment, it can be hazardous to the equipment itself. With electrical equipment it can be hazardous to any humans that need to be around the equipment.

Best regards,

Sam Gillett aka Mars Probe @ Starship Intrepid 1-972-221-4088
Last 8-bit BBS in the Dallas area. Commodore lives!

Joe Forster/STA
sta@c64.org

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From Newsgroup: comp.sys.cbm


On 2 Jul 2003, Joe Forster/STA wrote:

Hi Agemixer,

Ouch. Why in the moon the parallel port has no grounding?

The cable looks like a bomb. Easily fixed...
[...]
If they first made a proper design of this cable, they would have no need to type in such a bother...

It is very comforting to know that such omniscient individuals are
still frequenting this newsgroup. Perhaps, next time, you might
wanna join us in the development of a new cable if you're so aware
of all possible problems...

Ok, sorry.. :)

But what could annoy more than a broken disk drive?

Well.. Let us think about it... If i would have constructed
that cable, i consider it is not safe enough and keep it for myself
only. No question of selling such a cable. Actually i would have
buffered all the ports to save the never-ending CIA and VIA chips :-)

Another issue comes up when i start to sell my stuff... A Finnish
consumer protection law takes a good part on such notions in law as involuntary manslaughter, breaking the property etc. I once knew a professional electrician under an accusation.

--
Agemixer/Skalaria - "First run, then load."

email: agespam@japo.fi pass: "C64 mailinki" to the Subject: line
Spam filter is on

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From Newsgroup: comp.sys.cbm


On 2 Jul 2003, Joe Forster/STA wrote:

Hi Daniel,

But mayby Joe should take this discussion in count and
change the design of the parallel part

Agreed. As soon as we discuss this - with Nicolas, Womo and Mr.Axel -,
I'll do what I can about this.

Ofcourse... I don't resist.

As far as I remember, Mr.Axel had a reason to keep us from using
another GND connection - but I don't remember at all what the reason
exactly was! <:-) - and now Womo is also thinking about the two GND
lines possibly creating a "receiver loop"

Please, let me know too :-)

--
Agemixer/Skalaria - "First run, then load."

email: agespam@japo.fi pass: "C64 mailinki" to the Subject: line
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From Newsgroup: comp.sys.cbm


On Wed, 2 Jul 2003, Daniel Karlsson wrote:

In my opinion electronic parts for end users are too
expensive in general. Whenever I think about producing
some C64 hardware stuff for a handful of people I end up
with prices between 50 and 150 EUR, if I take
manufacturing costs and ensurances (2 years warranty and
other) into account...
My full respect goes to Joe and his friends who do a
really great job for this little money.

I agree in both parts, but it's no doubts about it: Electronic parts are
much cheaper in Germany than in Sweden or, maby, electronic parts are much more expensive in Sweden than in rest of the "first" world.

And Finland...

... the price can be compared with the product quality ;-)

No electronics manufacturers, no hobbyists.

--
Agemixer/Skalaria - "First run, then load."

email: agespam@japo.fi pass: "C64 mailinki" to the Subject: line
Spam filter is on

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From Newsgroup: comp.sys.cbm

Allowing a "floating ground" condition to
exist is poor design. Not only in computer equipment, but in other electronic and electrical equipment as well.
In the case of computer and solid state electronic equipment, it can be hazardous to the equipment itself. With electrical equipment it can be hazardous to any humans that need to be around the equipment.

I agree. On the other hand, adding additional grounds to equipment
that already has grounded components can create problems too. A "ground
loop" can introduce hum and noise into a system (including computer
equipment) that's very difficult to deal with sometimes. My stereo at home
runs off one outlet and my DSS receiver off another. Connecting the two for better TV sound from the amplifier produces an intermittant hum in the
sound and an annoying "lockup" problem (picture freeze) in the DSS. Microprocessors hate ground loops.
I recently ran into a similar ground fault problem when one Commodore
user complained of a wavy C64 picture on his 1702 monitor. Both computer
and monitor checked out OK. Turns out he is running his equipment from
several AC outlets. Each CBM device has a three wire power cord so each is grounded. The little bit of difference in electrical potential between
outlet grounds is enough to create that picture distortion. I suggested he
run all his hardware from one outlet by using a power strip. It adds surge protection as a bonus. I'll follow my own advice for my stereo system...
when I get some time. :-)

Ray

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From Newsgroup: comp.sys.cbm


On Wed, 2 Jul 2003, Daniel Karlsson wrote:

I'll wait for the result of your discussion then. I'm not an electrician ither so it's better to wait until the professionals have talked it through. Stupid of me not to talk with Nicolas directly but I didn't think of that.
If isn't possible to ground the parallel part separetely, maby you should make note that one never should have the parallel part of the cable
connected to the PC if one disconnect the serial (XE) part, as Pekka Takala stated in another message. I hope that everything is going to work out, as I was going to help Ed and Joe/WD to transfere a couple of hundred disks in
the near future, and the parallel connection realy makes a difference :).

If i had that cable, i should have done it already... The disk drive components inside are getting rare. You can always remove it later, if it
is for some trouble...

--
Agemixer/Skalaria - "First run, then load."

email: agespam@japo.fi pass: "C64 mailinki" to the Subject: line
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"Agemixer" <agespam@NOSPAM.japo.fi> skrev i meddelandet news:Pine.LNX.4.44.0307030048480.12074-100000@aapo.japo.fi...

On Wed, 2 Jul 2003, Daniel Karlsson wrote:

Yes I'll do this, I just don't follow your numbers. I use a parallel

game

plug sollution as decribed here: http://sta.c64.org/parport41c.html with this parallel cable: http://sta.c64.org/xp1541c2.html. Now I suppose

that

you mean that I should connect line 18-25 on the cable with GND

somewhere in

the drive. Is this what you mean? If so what place in the drive would be

the

best to use as ground, or is it egal (what's that in english) where I

take

ground (i.e. could I e.g. use the grounded C3 as ground for the parallel connection?

Ok, i cleared my head up a little.. The addition for grounding would look like this:

The drive part:

VIA ground, pin 1 <-----------------------> 1541 parallel port
(pins 13..15)

The cable part:

1541 parallel port <-----------------------> PC LPT connector
(connector pins 13...15) (connector pins 18...25)

1 wire is needed for both both 1541 and cable for the grounding.

I'm with you here, I think.

...

In a respond to some other's statements, I don't see any trouble with this "extra" grounding... Unless the cable does not act like "bus". I suppose
you have a bus-like cable anyway.

Now this is just a recommendation, not an advice... :-)

So you need: 1541Par <---> 1541Ser <-----------------> LPT
instead of: 1541Par <-------------> LPT <---------------> 1541Ser

Now I'm lost again :). I can't really read your artwork here. Do you mean
that both the cables you have written should be read as Y-formed cables? My current cable is Y-formed with the LPT as joint connection separated in a serial cable (XE1541) and a parallel cable with 8 data lines to the 1541.

What is a bus-like cable? (Se explanation below if it seems like a silly question :)).

...type of cable. Of course the latter cable is "longer".

Ofcourse both would do, but take care it is a bus: always wire the
ground the similiar route the cable was originally constructed. If you get
a triangle instead of one route, it is not a bus... if the wires are not equally long, this MAY cause trouble... not recommended in "high" frequencies. I know this will be obvious to you, but just a reminder...
:-)

Not at all actually :). Mind you I'm _not_ an electrician, I'm a philosopher
in spe, but I think I understand what you mean. We want to connect pin 1 of
the VIA and pin 2 of the serial port via two separate (physical) lines to
LPT pin 18-25, right? In my mind this seams to be a straight (electronical/logical) line from the PC to the drive, even though it is separated in two physical lines. I presuppose here that all grounding points
in the drive are connected with each other so that it doesn't matter if we
have two physical lines, with the same resistans, going from the 1541, as
long as they are connected to the same grounding signal at the LPT (18-25). Then the grounding signal should be equaly distributed over the two lines.
This make think of another thing. If one would do it this way, what will
happen with the grounding if one would do the same thing as I have been
doing, i.e. use the serial part connected to the C128 while still having the parallel cable connected to the PC LPT and all three devices were up and running? The C128 ground would be directly connected to the LPT ground via
the 1541. Would this be wise or could this damage the C128, the 1541 or the
PC or course trouble in any way?

...

Ignored the last part :).

Regards
/djk


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Randy McLaughlin wrote:

In OE 6 select tools->options->send->(news sending format, plain
text settings):

Make sure indent the original text with ">" (or what-ever)

95% sure he did this, as most of the time the indenting in his
postings works. I also had a few contacts where Outlook simply
refused to do it, without apparent reason. Daniel, I suggest you
check out OE-quotefix, a _very_ useful freeware add-on for Outlook.
That'll put unreliabilities like this to an end.

http://flash.to/oe-quotefix/

(I can't stop slapping my own shoulder every day for installing
this!) ;-)

That's the program I used to use. Thanks for remining me to install
it and the link. Works much better now :).

Regards
/djk

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Ray Carlsen wrote ...

Allowing a "floating ground" condition to
exist is poor design. Not only in computer equipment, but in other
electronic and electrical equipment as well.
In the case of computer and solid state electronic equipment, it can be
hazardous to the equipment itself. With electrical equipment it can be
hazardous to any humans that need to be around the equipment.

I agree. On the other hand, adding additional grounds to equipment
that already has grounded components can create problems too. A "ground
loop" can introduce hum and noise into a system (including computer >equipment) that's very difficult to deal with sometimes. My stereo at home >runs off one outlet and my DSS receiver off another. Connecting the two for >better TV sound from the amplifier produces an intermittant hum in the
sound and an annoying "lockup" problem (picture freeze) in the DSS. >Microprocessors hate ground loops.

If one outlet has an intermittent ground connection that could cause your problem. An intermittent connection on the hot wire or the neutral wire
will show up as flickering lights. But a bad ground often won't be noticed until you interconnect equipment on both circuits.

Hope I worded that well enough to make it understandable. I'm kind of tired tonight.

Best regards,

Sam Gillett aka Mars Probe @ Starship Intrepid 1-972-221-4088
Last 8-bit BBS in the Dallas area. Commodore lives!





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