CGA to SCART - UK Vintage Radio Repair and Restoration Discussion Forum

paul.brett · 17th Aug 2007, 4:58 pm

Hi guys,

I picked up a CGA to SCART converter at last weekends Kings Lynn radio rally, and decided to try it today using my Amstrad PC1640HD30-MD.

Removing the signal lead (DB9 male) from the computer end, I put the new cable into the socket, and the Amstrad turned itself off.

I re-connected the Amstrad MD display, but the unit refused to come on.

I thought it was a total disaster, as the Amstrad would NOT come on at all after that. A few minutes later, and I heard a faint 'click' inside the monitor, and when power was re-applied, it sprang back to life.

Now my questions:

1. Is it likely this CGA to SCART unit is faulty in some way?

2. Should I have altered some of the dip switches on the Amstrad before trying it? (It is being used with a MD mono monitor and the moment).

Maybe something a little more standard than the Amstrad (with power for the base unit coming from the monitor) would have met with more success. I fear for the safety of my treasured IBM PC and AT. What do you think?

Paul.

Nickthedentist · 17th Aug 2007, 5:06 pm

Hi Paul,

Was that my dad's old PC1640 with the dodgy HDD that you collected from me a year or two ago?

Anyway, I am 90% sure that this used to run OK with a home-made PSU (from J Bull Electrical) and an ancient, green-screen IBM monitor. My PC1512 definitely did (I bought it NOS with no monitor, so had to improvise).

In view of this, it suggests that the power supply in the Amstrad monitor is designed to shut down if the signals plug is removed from the PC. So maybe if you rigged up an external supply, you might find everything works ok.

I do have a photocopied manual for the PC1640 somewhere. Would you like it (assuming I ever find it)?

Nick.

paul.brett · 17th Aug 2007, 5:09 pm

Nick,

Do you know, it hadn't even occured to me to read the manual? (I do have one.) That's laziness for you!

From the chain of events, I guess you're right about the signal lead requirement. Maybe I will risk a quick go of the unit with my IBM PC.

Cheers.

Paul.

Nickthedentist · 17th Aug 2007, 5:13 pm

Quote:

Originally Posted by paul.brett

Do you know, it hadn't even occured to me to read the manual? (I do have one.)

I really meant the service manual, i.e. the one with circuit diagrams in it. But the user manual has got pin connection details in it too, I think.

Do you have both?

Dave Moll · 17th Aug 2007, 7:29 pm

The user manual gives the DIP settings for the various monitor types, but I can't find a pinout for anything other than the serial port.

Dave Moll · 17th Aug 2007, 10:09 pm

The pinout for the power connector is in the Technical Reference Manual:

plumbweiss · 17th Aug 2007, 11:07 pm

But surely the Amstrad monitor PSU is used to supply the PC, meaning the PC wont power up without its own monitor??

Nickthedentist · 17th Aug 2007, 11:19 pm

Quote:

Originally Posted by plumbweiss

But surely the Amstrad monitor PSU is used to supply the PC, meaning the PC wont power up without its own monitor??

Two separate connectors... so in theory, you should be able to leave the power one connected to the original monitor, whilst connecting the signals one to any monitor of your choice.

plumbweiss · 18th Aug 2007, 2:35 pm

Doesnt the monitor PSU just fall into standby if no video is present?

Dave Moll · 18th Aug 2007, 6:15 pm

My 1640 starts up fine without the monitor data cable plugged in. Once I plug it back in the display is as expected.

17th Aug 2007, 4:58 pm	#1
paul.brett Tetrode Join Date: Dec 2005 Location: Wisbech, Cambridgeshire, UK. Posts: 97	CGA to SCART Hi guys, I picked up a CGA to SCART converter at last weekends Kings Lynn radio rally, and decided to try it today using my Amstrad PC1640HD30-MD. Removing the signal lead (DB9 male) from the computer end, I put the new cable into the socket, and the Amstrad turned itself off. I re-connected the Amstrad MD display, but the unit refused to come on. I thought it was a total disaster, as the Amstrad would NOT come on at all after that. A few minutes later, and I heard a faint 'click' inside the monitor, and when power was re-applied, it sprang back to life. Now my questions: 1. Is it likely this CGA to SCART unit is faulty in some way? 2. Should I have altered some of the dip switches on the Amstrad before trying it? (It is being used with a MD mono monitor and the moment). Maybe something a little more standard than the Amstrad (with power for the base unit coming from the monitor) would have met with more success. I fear for the safety of my treasured IBM PC and AT. What do you think? Paul.

17th Aug 2007, 5:06 pm	#2
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,861	Re: CGA to SCART Hi Paul, Was that my dad's old PC1640 with the dodgy HDD that you collected from me a year or two ago? Anyway, I am 90% sure that this used to run OK with a home-made PSU (from J Bull Electrical) and an ancient, green-screen IBM monitor. My PC1512 definitely did (I bought it NOS with no monitor, so had to improvise). In view of this, it suggests that the power supply in the Amstrad monitor is designed to shut down if the signals plug is removed from the PC. So maybe if you rigged up an external supply, you might find everything works ok. I do have a photocopied manual for the PC1640 somewhere. Would you like it (assuming I ever find it)? Nick.

17th Aug 2007, 5:09 pm	#3
paul.brett Tetrode Join Date: Dec 2005 Location: Wisbech, Cambridgeshire, UK. Posts: 97	Re: CGA to SCART Nick, Do you know, it hadn't even occured to me to read the manual? (I do have one.) That's laziness for you! From the chain of events, I guess you're right about the signal lead requirement. Maybe I will risk a quick go of the unit with my IBM PC. Cheers. Paul.

17th Aug 2007, 7:29 pm	#5
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,130	Re: CGA to SCART The user manual gives the DIP settings for the various monitor types, but I can't find a pinout for anything other than the serial port. __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

17th Aug 2007, 10:09 pm	#6
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,130	Re: CGA to SCART The pinout for the power connector is in the Technical Reference Manual: Attached Thumbnails __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

17th Aug 2007, 11:07 pm	#7
plumbweiss Retired Dormant Member Join Date: Nov 2006 Location: Manchester, UK. Posts: 157	Re: CGA to SCART But surely the Amstrad monitor PSU is used to supply the PC, meaning the PC wont power up without its own monitor??

18th Aug 2007, 2:35 pm	#9
plumbweiss Retired Dormant Member Join Date: Nov 2006 Location: Manchester, UK. Posts: 157	Re: CGA to SCART Doesnt the monitor PSU just fall into standby if no video is present?

18th Aug 2007, 6:15 pm	#10
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,130	Re: CGA to SCART My 1640 starts up fine without the monitor data cable plugged in. Once I plug it back in the display is as expected. __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)