Using an IBM 3270 Terminal as a monitor - UK Vintage Radio Repair and Restoration Discussion Forum

ghinzani · 1st May 2009, 8:47 am

One of my pals tells me years ago when his Dad took away his bedroom TV for some misdemeanour he resorted to using a 3270 type dumb terminal hooked up to a VCR to act as a modulator and he was able to watch TV? Is that bull?

I've looked at an old one Ive got hanging round and theres a cable input that close to an aerial socket but slightly smaller. Would it be possible to get a TV picture on it via a VCR or Freeview box with modulator built in? I know its masochistic but it appeals to me, it would look like a torture scene from Blakes 7 or the video effects on 1970s Top of the Pops for sure but it wouldnt half be cool if it worked.

Anyone have any insight as to if its a possibility? Have posted this question on a number of forums to get a bit of coverage, so apologies if you read it elsewhere.

Station X · 1st May 2009, 9:58 am

Some older VCRs had a composite video output, often from a BNC type socket. If the monitor will accept 625 line composite video then this will work. The Microvitec Cub monitors popular with BBC computer users had this facility.

It's also possible for some VCRs to output composite video from the scart socket, but you'd need an adaptor lead.

ronbryan · 1st May 2009, 10:22 am

I'm not sure that a 3270 terminal has any video inputs. My recollection is that they connected to the cluster controller via a co-ax cable that used the Bi-Sync protocol.

Ron

Nickthedentist · 1st May 2009, 10:59 am

As Graham implies, some monitors often had a composite video input, which could be fed from any VCR or DVD player. See this thread: https://www.vintage-radio.net/forum/...ad.php?t=19958

N.

G0PKH - Pete · 1st May 2009, 11:35 am

Ron is quite correct.

I used to service these years ago.
They do indeed connect to a cluster controller using coax.
Behind the coax socket is usually a very comprehensive logic board. In fact in the case of the 3270 series, this board actually attaches to the back of the monitor unit. And comprises the weirdest of ICs all especially made for IBM usually square aluminium cased devices too, with all pins directly exiting the bottom.

Quite unserviceable even then.

Pete

ronbryan · 1st May 2009, 12:02 pm

Nick

The type of IBM 3270 terminal I was referring to is depicted here.

http://www.columbia.edu/acis/history/3270.html

Later emulations of 3270 terminals may well use monitors that have a video input.

Ron

ghinzani · 1st May 2009, 1:10 pm

Thanks for the replies chaps, perhaps the below pics will help some more?

http://www.facebook.com/photo.php?pi...9&id=520022145

http://www.facebook.com/photo.php?pi...4&id=520022145

Nickthedentist · 1st May 2009, 1:29 pm

Thanks, Ron. The ones I've seen with comp inputs were not IBM ones anyway

Nick.

ghinzani · 1st May 2009, 2:52 pm

Does anyone know what size and where I can get a coax end to plug into it? If so I will bung it on some co-ax cable and try and feed a signal into it. Thanks

Station X · 1st May 2009, 4:13 pm

That looks like a BNC socket to me. Does it have two radial pins sticking out from the outer conductor? You can buy BNC plugs complete with leads from Maplin.

It would be a waste of time trying to feed the signal from a TV aerial or modulator in there though. It definitely won't work. A video signal might work, but there's no way of knowing. Is the socket labelled?

julie_m · 1st May 2009, 4:24 pm

You could always try connecting the centre pin to pin 19 on a SCART connector and the outer to pin 17. BNC to phono adaptors used to be fairly common, as both these connectors were used for video signals before SCART became standard.

Station X · 1st May 2009, 4:51 pm

This would do the job, but at a price:-

http://www.maplin.co.uk/module.aspx?moduleno=4702

Itmog57 · 2nd May 2009, 9:39 am

Hi

Believe it or not, we still use these at work..(The are so reliable. We also have the Mono ones, about 300 in total. and muggins here has to repair them) The BNC connector is not Video, It is used to connect to an IBM mainframe (AS400/RS6000) via a device controller (Think of it being like an Ethernet switch or hub) Some of the models also have an RG45 or a Twinax connector. The DB25 connector is for connecting a printer to.
I looked at the possibility of converting one of these myself but decided it was to much effort. You have to find the print tracks to cut to put the video signals in and build a sync separator to get the frame and line sync to the output stages. The other problem is the output (Vid and sync) is monitored by the digital logic chips and they usually shut down the terminal thinking there is a fault. (And there's the sleep mode as well). Witt a Keyboard connected hold the spacebar ot the setup button down and switch on, The setup menus will the appear.

Regards

Ivor

Station X · 2nd May 2009, 10:47 am

So there you have it ghinzani. This terminal won't work as a TV monitor, so don't waste your money on a plug or lead.

ghinzani · 2nd May 2009, 7:53 pm

Thanks very much guys, so it will just have to stay sat there on the shelf looking pretty! Shame because Id really love a green screen monitor for TV... Any other uses for these dumb terminals? Fish tank?

ghinzani · 2nd May 2009, 10:33 pm

Quote:

Originally Posted by Itmog57

Hi

Believe it or not, we still use these at work..(The are so reliable. We also have the Mono ones, about 300 in total. and muggins here has to repair them) The BNC connector is not Video, It is used to connect to an IBM mainframe (AS400/RS6000) via a device controller (Think of it being like an Ethernet switch or hub) Some of the models also have an RG45 or a Twinax connector. The DB25 connector is for connecting a printer to.
I looked at the possibility of converting one of these myself but decided it was to much effort. You have to find the print tracks to cut to put the video signals in and build a sync separator to get the frame and line sync to the output stages. The other problem is the output (Vid and sync) is monitored by the digital logic chips and they usually shut down the terminal thinking there is a fault. (And there's the sleep mode as well). Witt a Keyboard connected hold the spacebar ot the setup button down and switch on, The setup menus will the appear.

Regards

Ivor

We used to use them regularly at my old work, especially as a fallback and I believe theres a lot of them out on sites at my new work - connected to mainframes and AS400s. To be fair we get so few issues with them I can see why they are not replaced, compared to the issues we get when using citrix and emulators. Also they dont suffer from Virus's. Long may they continue!

Jack Spark · 7th May 2009, 5:26 pm

I've installed many of these, as has been pointed out, they are usually used on IBM Mid range systems like the AS/400, which are/were very stable systems.
The peripheral equipment such as terminals weren't much different either, all solid pieces of kit and I'm not surprised to hear they are still being used today.

But in answer to the original question, any use as a video monitor?
Not without a great deal of time and effort and even then the results would be really poor.

Regards

J

1st May 2009, 8:47 am	#1
ghinzani Retired Dormant Member Join Date: May 2009 Location: Salisbury Posts: 5	Using an IBM 3270 Terminal as a monitor One of my pals tells me years ago when his Dad took away his bedroom TV for some misdemeanour he resorted to using a 3270 type dumb terminal hooked up to a VCR to act as a modulator and he was able to watch TV? Is that bull? I've looked at an old one Ive got hanging round and theres a cable input that close to an aerial socket but slightly smaller. Would it be possible to get a TV picture on it via a VCR or Freeview box with modulator built in? I know its masochistic but it appeals to me, it would look like a torture scene from Blakes 7 or the video effects on 1970s Top of the Pops for sure but it wouldnt half be cool if it worked. Anyone have any insight as to if its a possibility? Have posted this question on a number of forums to get a bit of coverage, so apologies if you read it elsewhere.

1st May 2009, 9:58 am	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Using an IBM 3270 Terminal as a monitor Some older VCRs had a composite video output, often from a BNC type socket. If the monitor will accept 625 line composite video then this will work. The Microvitec Cub monitors popular with BBC computer users had this facility. It's also possible for some VCRs to output composite video from the scart socket, but you'd need an adaptor lead. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

1st May 2009, 10:22 am	#3
ronbryan Octode Join Date: Jan 2003 Location: Guildford, Surrey, UK. Posts: 1,960	Re: Using an IBM 3270 Terminal as a monitor I'm not sure that a 3270 terminal has any video inputs. My recollection is that they connected to the cluster controller via a co-ax cable that used the Bi-Sync protocol. Ron

1st May 2009, 10:59 am	#4
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,864	Re: Using an IBM 3270 Terminal as a monitor As Graham implies, some monitors often had a composite video input, which could be fed from any VCR or DVD player. See this thread: https://www.vintage-radio.net/forum/...ad.php?t=19958 N.

1st May 2009, 11:35 am	#5
G0PKH - Pete Retired Dormant Member Join Date: Aug 2003 Location: Stansted Essex Posts: 263	Re: Using an IBM 3270 Terminal as a monitor Ron is quite correct. I used to service these years ago. They do indeed connect to a cluster controller using coax. Behind the coax socket is usually a very comprehensive logic board. In fact in the case of the 3270 series, this board actually attaches to the back of the monitor unit. And comprises the weirdest of ICs all especially made for IBM usually square aluminium cased devices too, with all pins directly exiting the bottom. Quite unserviceable even then. Pete

1st May 2009, 12:02 pm	#6
ronbryan Octode Join Date: Jan 2003 Location: Guildford, Surrey, UK. Posts: 1,960	Re: Using an IBM 3270 Terminal as a monitor Nick The type of IBM 3270 terminal I was referring to is depicted here. http://www.columbia.edu/acis/history/3270.html Later emulations of 3270 terminals may well use monitors that have a video input. Ron

1st May 2009, 1:10 pm	#7
ghinzani Retired Dormant Member Join Date: May 2009 Location: Salisbury Posts: 5	Re: Using an IBM 3270 Terminal as a monitor Thanks for the replies chaps, perhaps the below pics will help some more? http://www.facebook.com/photo.php?pi...9&id=520022145 http://www.facebook.com/photo.php?pi...4&id=520022145

1st May 2009, 1:29 pm	#8
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,864	Re: Using an IBM 3270 Terminal as a monitor Thanks, Ron. The ones I've seen with comp inputs were not IBM ones anyway Nick.

1st May 2009, 2:52 pm	#9
ghinzani Retired Dormant Member Join Date: May 2009 Location: Salisbury Posts: 5	Re: Using an IBM 3270 Terminal as a monitor Does anyone know what size and where I can get a coax end to plug into it? If so I will bung it on some co-ax cable and try and feed a signal into it. Thanks

1st May 2009, 4:13 pm	#10
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Using an IBM 3270 Terminal as a monitor That looks like a BNC socket to me. Does it have two radial pins sticking out from the outer conductor? You can buy BNC plugs complete with leads from Maplin. It would be a waste of time trying to feed the signal from a TV aerial or modulator in there though. It definitely won't work. A video signal might work, but there's no way of knowing. Is the socket labelled? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

1st May 2009, 4:24 pm	#11
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Using an IBM 3270 Terminal as a monitor You could always try connecting the centre pin to pin 19 on a SCART connector and the outer to pin 17. BNC to phono adaptors used to be fairly common, as both these connectors were used for video signals before SCART became standard. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

1st May 2009, 4:51 pm	#12
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Using an IBM 3270 Terminal as a monitor This would do the job, but at a price:- http://www.maplin.co.uk/module.aspx?moduleno=4702 __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

2nd May 2009, 9:39 am	#13
Itmog57 Retired Dormant Member Join Date: Mar 2009 Location: Leicester (Queniborough) Posts: 14	Re: Using an IBM 3270 Terminal as a monitor Hi Believe it or not, we still use these at work..(The are so reliable. We also have the Mono ones, about 300 in total. and muggins here has to repair them) The BNC connector is not Video, It is used to connect to an IBM mainframe (AS400/RS6000) via a device controller (Think of it being like an Ethernet switch or hub) Some of the models also have an RG45 or a Twinax connector. The DB25 connector is for connecting a printer to. I looked at the possibility of converting one of these myself but decided it was to much effort. You have to find the print tracks to cut to put the video signals in and build a sync separator to get the frame and line sync to the output stages. The other problem is the output (Vid and sync) is monitored by the digital logic chips and they usually shut down the terminal thinking there is a fault. (And there's the sleep mode as well). Witt a Keyboard connected hold the spacebar ot the setup button down and switch on, The setup menus will the appear. Regards Ivor

2nd May 2009, 10:47 am	#14
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Using an IBM 3270 Terminal as a monitor So there you have it ghinzani. This terminal won't work as a TV monitor, so don't waste your money on a plug or lead. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

2nd May 2009, 7:53 pm	#15
ghinzani Retired Dormant Member Join Date: May 2009 Location: Salisbury Posts: 5	Re: Using an IBM 3270 Terminal as a monitor Thanks very much guys, so it will just have to stay sat there on the shelf looking pretty! Shame because Id really love a green screen monitor for TV... Any other uses for these dumb terminals? Fish tank?

7th May 2009, 5:26 pm	#17
Jack Spark Retired Dormant Member Join Date: Aug 2008 Location: London, UK. Posts: 47	Re: Using an IBM 3270 Terminal as a monitor I've installed many of these, as has been pointed out, they are usually used on IBM Mid range systems like the AS/400, which are/were very stable systems. The peripheral equipment such as terminals weren't much different either, all solid pieces of kit and I'm not surprised to hear they are still being used today. But in answer to the original question, any use as a video monitor? Not without a great deal of time and effort and even then the results would be really poor. Regards J