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Connecting a QX16 to a QX10 monitor help needed!

vprada

vprada

Member
Joined
Dec 14, 2021
Messages
38
Location
Miami, U.S.A
I know this have been duscussed before but i didnt want to reopen an old thread... so here is my issue..

Following the documentation I found on the qx-16 tech documents and the qx-10 tech document I made a cable to connect the qx-16 video port to the qx-10 monitor.

I'm mapping the pins as follow

QX-16 ------> Q701A monitor.
7 ------- > 1
4 -------- > 3
5 -------- > 2
2 -------- > 7
2 -------- > 5

All dip switches on the QX-16 are ON ...

When I turn the QX-16 on, the Monitor comes UP (i made a cable to provide 12V to the monitor) but I don't see anything on the display... If I crank up the monitor's brightness knob I can see the raster but cant see any text...

I did check with the scope and I see the horiz and vert pulses fed to the monitor and also i see activity on the monitor's video input...

Any advice for any additional troubleshooting? Is there any way I can test the monitor to discard is broken? I actually believe the qx16 is booting but i cant see if it actually did....

Im looking forward to your replies...
Thanks in advance!

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It does appear that you were successful in getting power to the monitor, so that's not an issue. I would turn on the QX16 on again and you should see the power LED on plus the drive A LED come on. You should also hear the drive motors running. If you have a system disk, I would insert it into drive A, but only if the drive's LED is on and then push the drive button to engage the drive latching. At that point you should hear the drive attempt to read the disk. You don't need to press any keyboard key. If all that happens then most likely the computer is booting and you just have a video issue. If no attempt to read the disks then you have larger issue to solve.

Note: I am using an original QX-10 cable with my QX16, but I modified the monitor and so never looked up the pin outs for the cable. If you think you have a video issue, I'd double/triple check the pin out and also your wiring. Hopefully, you'll find the problem without needing to troubleshoot the QX16 itself.
 
DeltaDon said:
It does appear that you were successful in getting power to the monitor, so that's not an issue. I would turn on the QX16 on again and you should see the power LED on plus the drive A LED come on. You should also hear the drive motors running. If you have a system disk, I would insert it into drive A, but only if the drive's LED is on and then push the drive button to engage the drive latching. At that point you should hear the drive attempt to read the disk. You don't need to press any keyboard key. If all that happens then most likely the computer is booting and you just have a video issue. If no attempt to read the disks then you have larger issue to solve.

Note: I am using an original QX-10 cable with my QX16, but I modified the monitor and so never looked up the pin outs for the cable. If you think you have a video issue, I'd double/triple check the pin out and also your wiring. Hopefully, you'll find the problem without needing to troubleshoot the QX16 itself.
Click to expand...
Hey Don.. thanks for the reply.

I actually have the boot disk with CP/M. Power led is on. Disk led is on. When I insert the disk the machine starts reading the disk until it stops, and drive led goes off. I'm pretty sure I have vertical and horizontal sync, and I actually can see a little change in the monitor right when the drive stops reading the disk.. like a tiny change in vertical refresh.. I would assume that even without the disk, I should be seeing the RAM check and the "insert disk to boot" or some kind of message on that realm.

May I ask what did you change in the monitor ? did you just moved the cables inside the monitor ? that may be a better idea that trying to patch the cable ....
 
If you are hearing the drive seek then I'd guess the computer is booting. When you turn on the QX the my monitor displays a message with the bios version and the insert disk to boot message. So yes, that's what you should see.

I bought my QX16 without a monitor or cable and then started searching for both. I found a video cable on eBay, but searched for over a year looking for a QX16 monitor and gave up and picked up the next QX10 monitor that popped up and had to figure out how to power it up. I didn't have the pin out for the QX10 cable and so I set about adding 12vdc to the monitor. I used a bench supply connected to the internal fuse (I think) to power the monitor and crossed my fingers and powered up the 16 hoping to see video. It worked. It took maybe 400-500mamps to power the monitor and so I bought a 1 amp wall wart and added a jack to the monitor and that's how I'm powering my monitor still.

I haven't been doing much with the QX16 of late on;y because I have so many other projects I'm trying to finish. I really need to get a DOS machine going with some 5.25" drives so I can use IMD and such programs to create some CP/M formatted disks and add software to a few machines. I've been haven't problems getting a working drive and/or PC motherboard's floppy controller combo to function. I even purchased the TexElec 4 floppy controller board in the hopes that would solve my issues. Ditto with getting a greaseweazle to work - lack of working 5.25's. Some health issues and a colder than usual basement have slowed me down too.
 
I got my QX-16 last year and it took me a while to clean it up. Then I did a recap of the power supply and that didnt went well..I dont know if my recapping broke the power supply or if the power supply was already broken... I found a qx-10 monitor listed on ebay that I got thinking I could use it on the qx-16, but the person who listed the monitor didnt know if the monitor was operational or not..

long story short, i got a new power supply from mouser and replaced the broken power supply of the qx16 with a more modern equivalent. Now that the qx16 is powering up, Im trying to have the monitor working, and right now Im in a place where I dont known if the monitor is broken or if the Frankenstein cable I made up is the culprit of not having video when I turn the computer on...

I found the service manual of the monitor, and I'm planning to check some test points inside the monitor for wave forms... I'll write an update on how everything goes...

Once I have an OS working on the QX-16 I may be able to write a program to create an MS DOS disk... If I reach that point I will be more than happy to send you a dos disk for your qx16

Thank you Don
 
the background of your CRT should be almost black and not so bright that you can see the diagonal retrace.
If the "INSERT DISK" text was on screen you wouldn't see it. You need to lower the brightness whether externally
or internally. Are you seeing the vertical and hoizontal sync signals on the monitor jack ? Those would help set the black level.
QX10 monitor jack.JPG
 
I actually set the brightness to its highest and that's when I realized the monitor was turning on; at the beginning the screen was completely dark ...

I believe the monitor wont turn on unless there is a sync signal... unfortunately I dont have the knowledge to tell for sure if what im seeing on the video input is indeed a video signal or something else.

I dont quite understand the picture you posted..is that specific for the qx16?
 
No sorry it's for the QX-10 but illustrates the signals going to the mono monitor.
It looks to me like the QX16 is expecting a color display? This is the path from the QX16 to it's color CRT (more like CGA signals).
I don't think these can be cross connected ?
QX16 color.JPG
 
the qx16 supports both, mono and color monitors. In my case I'm trying the monochrome connection using a custom cable (the qx16 have an 8 pin din output, but the monitor have a 7 pin din output)... Im looking for a way to test the monitor as I believe the issue is the monitor and not the computer...
 
Don...I actually going to make a second cable and send it to you..no need to return it...Just send me tour address over pm... I really appreciate your offer!
 
I finally got the monitor to work, and the issue was actually the cable I made. I was following a diagram I found here in the forum that say you should use the green output pin for the video but that is actually incorrect, you should use the intensity pin (pin 1) as video output.

in summary this is the correct wiring to connect a qx-16 to a Q702A (QX-10) monitor

QX16 ----------------- QX10
===================
PIN 1 -------> PIN 1
PIN 2 -------> PIN 7
PIN 4 -------> PIN 3
PIN 5 -------> PIN 2
====================
Not necessarily accurate to use colors but in my case the connections went

Brown to Brown
Blue to white
Yellow to Green
Orange to Yellow




20260206_204232.jpg
 
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