Alexandria, VA (metro DC).
Sent from my iPhone
On Oct 4, 2013, at 7:52 PM, "Dave McGuire" <mcguire at neurotica.com> wrote:
Where are you located?
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
On Oct 4, 2013, at 7:16 PM, Michael Holmes <mholmes10 at hotmail.com> wrote:
I have two VaxStation 3100's that I bought some time back but didn't have time to mess with until now.
Unlike my DEC 3000, the serial console is an MMJ port and not a DB9 serial port.
Does anyone have an excess or spare MMJ to DB9 adaptor, or know where I can purchase an inexpensive one?
I tired hooking up my multisync monitor I have hooked up to my DEC 3000, but I don't think the graphic card is set to a setting within the monitor's range, as nothing shows up.
Thanks in advance.
Mike
Where are you located?
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
On Oct 4, 2013, at 7:16 PM, Michael Holmes <mholmes10 at hotmail.com> wrote:
I have two VaxStation 3100's that I bought some time back but didn't have time to mess with until now.
Unlike my DEC 3000, the serial console is an MMJ port and not a DB9 serial port.
Does anyone have an excess or spare MMJ to DB9 adaptor, or know where I can purchase an inexpensive one?
I tired hooking up my multisync monitor I have hooked up to my DEC 3000, but I don't think the graphic card is set to a setting within the monitor's range, as nothing shows up.
Thanks in advance.
Mike
I have two VaxStation 3100's that I bought some time back but didn't have time to mess with until now.
Unlike my DEC 3000, the serial console is an MMJ port and not a DB9 serial port.
Does anyone have an excess or spare MMJ to DB9 adaptor, or know where I can purchase an inexpensive one?
I tired hooking up my multisync monitor I have hooked up to my DEC 3000, but I don't think the graphic card is set to a setting within the monitor's range, as nothing shows up.
Thanks in advance.
Mike
On Fri, 4 Oct 2013, Dave McGuire wrote:
On 10/04/2013 02:07 PM, Ian McLaughlin wrote:
Please note that a discharged CRT can build up a static charge again
just by sitting on a shelf. Always re-discharge the tube when coming
back to a tube you've left alone for a while.
This is dielectric absorption. It happens with all capacitances,
including capacitance in things that are not capacitors, like CRTs.
-Dave
I'm suddenly reminded of my largely unrelated habit of always touching a door handle with the back of my hand first and never the fingers or the palm.
--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects
On Oct 4, 2013, at 2:07 PM, Ian McLaughlin <ian at platinum.net> wrote:
On Oct 4, 2013, at 10:56 AM, Cory Smelosky <b4 at gewt.net> wrote:
Yeah. I know they're in the kV range. I'd appropriate discharge the CRT itself...but I lack the appropriate HV grounding wires.
A flat-blade screwdriver and an alligator clip lead. Clip the lead to the shaft of the screwdriver and to the metal chassis of the monitor. Work the flat blade under the rubber cup where the anode wire attaches to the CRT. Be prepared for a loud POP and a flash.
Be careful where you place your fingers while doing this.
Don't do it like my father did: he allowed his finger to wander onto the shaft of the screwdriver. Got seriously zapped, enough so that he jumped back 6 feet (from a squatting position). Not a CRT -- an 800 volt high current supply, B+ for a transmitter.
He wasn't hurt, but that taught me to be very careful with that procedure.
paul
On Fri, 4 Oct 2013, Ian McLaughlin wrote:
On Oct 4, 2013, at 10:56 AM, Cory Smelosky <b4 at gewt.net> wrote:
Yeah. I know they're in the kV range. I'd appropriate discharge the CRT itself...but I lack the appropriate HV grounding wires.
A flat-blade screwdriver and an alligator clip lead. Clip the lead to the shaft of the screwdriver and to the metal chassis of the monitor. Work the flat blade under the rubber cup where the anode wire attaches to the CRT. Be prepared for a loud POP and a flash.
Believe it or not I don't HAVE any alligator clip leads laying around!
CRT is now discharged.
If the loud pop scares you, then you can build a resistor into the grounding lead. I built one of these many many years ago, and it lives in my toolbox for just this event.
Resistors I have plenty of. ;)
Please note that a discharged CRT can build up a static charge again just by sitting on a shelf. Always re-discharge the tube when coming back to a tube you've left alone for a while.
Also, Brian's advice about the hand in the pocket is important. Current is looking for ground. If your other hand is holding the chassis, then the shortest path to ground is across your heart. Not good. From your hand down your leg to ground, while not good, is at least not across your heart.
Ian
--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects
On 10/04/2013 02:07 PM, Ian McLaughlin wrote:
Please note that a discharged CRT can build up a static charge again
just by sitting on a shelf. Always re-discharge the tube when coming
back to a tube you've left alone for a while.
This is dielectric absorption. It happens with all capacitances,
including capacitance in things that are not capacitors, like CRTs.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
Ian McLaughlin <ian at platinum.net> writes:
On Oct 4, 2013, at 10:56 AM, Cory Smelosky <b4 at gewt.net> wrote:
=20
Yeah. I know they're in the kV range. I'd appropriate discharge the =
CRT itself...but I lack the appropriate HV grounding wires.
=20
A flat-blade screwdriver and an alligator clip lead. Clip the lead to =
the shaft of the screwdriver and to the metal chassis of the monitor. =
Work the flat blade under the rubber cup where the anode wire attaches =
to the CRT. Be prepared for a loud POP and a flash.
CRT is now discharged.
If the loud pop scares you, then you can build a resistor into the =
grounding lead. I built one of these many many years ago, and it lives =
in my toolbox for just this event.
Please note that a discharged CRT can build up a static charge again =
just by sitting on a shelf. Always re-discharge the tube when coming =
back to a tube you've left alone for a while.
Also, Brian's advice about the hand in the pocket is important. Current =
is looking for ground. If your other hand is holding the chassis, then =
the shortest path to ground is across your heart. Not good. =46rom =
your hand down your leg to ground, while not good, is at least not =
across your heart.
It was Dave's advice but I would have stated it if he had not. In college,
a friend and I used to repair TV sets we found placed out for junk colection
and then, we'd sell them for beer money! ;) I took my fair share of shocks.
One discharge was through my thumb and there's still a tell-tale mark there.
--
VAXman- A Bored Certified VMS Kernel Mode Hacker VAXman(at)TMESIS(dot)ORG
Well I speak to machines with the voice of humanity.
On Oct 4, 2013, at 10:56 AM, Cory Smelosky <b4 at gewt.net> wrote:
Yeah. I know they're in the kV range. I'd appropriate discharge the CRT itself...but I lack the appropriate HV grounding wires.
A flat-blade screwdriver and an alligator clip lead. Clip the lead to the shaft of the screwdriver and to the metal chassis of the monitor. Work the flat blade under the rubber cup where the anode wire attaches to the CRT. Be prepared for a loud POP and a flash.
CRT is now discharged.
If the loud pop scares you, then you can build a resistor into the grounding lead. I built one of these many many years ago, and it lives in my toolbox for just this event.
Please note that a discharged CRT can build up a static charge again just by sitting on a shelf. Always re-discharge the tube when coming back to a tube you've left alone for a while.
Also, Brian's advice about the hand in the pocket is important. Current is looking for ground. If your other hand is holding the chassis, then the shortest path to ground is across your heart. Not good. From your hand down your leg to ground, while not good, is at least not across your heart.
Ian
Dave McGuire <mcguire at neurotica.com> writes:
On 10/04/2013 01:47 PM, Brian Schenkenberger, VAXman- wrote:
Does the VT320 have a similar pot for width and height? The width and
height are off on mine.
Inside on the board. Google for the VT320 service guide and it should tell
you the alignment procedure.
Cory, be very careful in there. You are technically astute, and I
know you have a serious knack for this stuff, but there are voltages on
and around that board that are unconditionally lethal.
A finger-to-finger shock will hurt, but a hand-to-hand shock can kill
you. Keep one hand in your pocket or behind your back when the other
hand is inside that chassis. Also, never do this kind of work when
you're the only person in the building.
Sage advice!
Use a non-conducting adjustment tool to trim those pots; not a metal shaft
screwdriver.
--
VAXman- A Bored Certified VMS Kernel Mode Hacker VAXman(at)TMESIS(dot)ORG
Well I speak to machines with the voice of humanity.
