Author Topic: how to drive CRT model MD1000-390? (Read 6481 times)

ali6x944 · « **on:** February 14, 2016, 06:52:19 pm »

how to drive CRT model MD1000-390 to display anything?
how to interface with it?

uncle_bob · « **Reply #1 on:** February 14, 2016, 08:33:37 pm »

Hi

That's an *old* CRT monitor.

I would bet that you feed it NTSC frame rate H and V sync pulses on individual pins. Video information would go in on it's own pin. All are 5V TTL inputs on the 9 pin connector. What ever it is, it will be very low resolution.

First thing to do would be to ohm out the 9 pin and find the ground (and any DC loads). Next step would be to power it up and see what pins have any voltage on them.

Bob

ali6x944 · « **Reply #2 on:** February 15, 2016, 06:07:13 pm »

Pins 1 and 10 were ground
Pins 2,3,5,6 were mesuering 0v
Pin 4 Vcc
Pins 9,7 were mesuering around -30v, -24.5v
Pin 8 was mesuering spot on -70v

All mesurments are all ground refrenced

uncle_bob · « **Reply #3 on:** February 15, 2016, 06:50:26 pm »

Hi

So all the stuff on the web that you see about this being a "TTL monitor" is dead wrong. At least it is dead wrong in terms of there being a TTL interface.

What you have there are good old vacuum tube grid voltages. It's a direct drive / high voltage drive monitor.

Best guess:

You will find horizontal deflection, vertical deflection and intensity(or blanking) in there. Focus could be on the connector or on the chassis. From the (now highly suspect) web pictures it should be magnetic deflection.

Next step would be to design up some high voltage drive circuits and start playing with the pins. Truthfully, if it was mine, that would cost me more than a black and white CRT monitor is worth (to me).

One quick question:

Does it show the manufacturing location anywhere on it? Franklin Park IL would be one possibility. If that's what it shows it would date the unit pretty accurately.

Bob

ali6x944 · « **Reply #4 on:** February 16, 2016, 04:12:31 am »

Its a display technologies inc monitor made in 1992 the tube it self is made by clinton electronic co in 1992 in the USA

uncle_bob · « **Reply #5 on:** February 16, 2016, 06:26:48 pm »

Quote from: ali6x944 on February 16, 2016, 04:12:31 am

Its a display technologies inc monitor made in 1992 the tube it self is made by clinton electronic co in 1992 in the USA

Hi

Ok so it's not a Motorola made monitor at all. They stopped making them in 1974 ... The part number and Google takes you to a Motorola unit.

Bob

ali6x944 · « **Reply #6 on:** February 16, 2016, 07:23:23 pm »

i know

ali6x944 · « **Reply #7 on:** February 16, 2016, 07:27:04 pm »

there is other similar products made by motorola, but i seem to never founded from display technologies inc for some reason?!?

ali6x944 · « **Reply #8 on:** February 16, 2016, 07:36:47 pm »

models like MD1000-190, MD1000-100..est....

ali6x944 · « **Reply #9 on:** February 16, 2016, 09:47:42 pm »

will i was wondering if i could drive it using D7220AD?

uncle_bob · « **Reply #10 on:** February 17, 2016, 12:27:52 am »

Hi

Some history:

Back in 1974 Motorola sold their TV plant in Franklin Park IL (technically Franklin Park North , but that is not really part of the story) to Panasonic of Japan. Panasonic changed a lot of things. I addition to TV's Motorola made a lot of similar "stuff". Once they were out of the TV business, others stepped in to sell replacement monitors. The key point: The old Motorola design was still what dictated the interface of the monitor. What came after was just a "clone" of the older unit. They made them to replace ones that died in old equipment.

NTSC video is not super hard to do as long as color is not involved. There were a *lot* of designs that did this back in the early 1970's. The problem you will get into is not so much generating the signal ... it's developing the high voltage drive "stuff" to interface to this monitor. Simply put, the most any chip will put out is 5V. You need several 0 to -70V signals to drive this beast.

Bob

ali6x944 · « **Reply #11 on:** February 18, 2016, 01:59:03 pm »

i saw this on the pcb :

ali6x944 · « **Reply #12 on:** February 18, 2016, 02:23:47 pm »

i don't know if it a high voltage drive high monitor, i searched in the datasheet and it didn't state any thing about pin 8 -SYNC. INPUT- drive voltage
the only other input is pin 10 -AMP. INPUT- which is rated for +10v max, -0.5v min, so I'm confused right now...
i well send photos of the pcb and ic parts numbers soon.

uncle_bob · « **Reply #13 on:** February 18, 2016, 06:05:53 pm »

Hi

Based on the voltages you measured on the 9 pin connector, that's a high voltage drive device. If you look those pins to any sort of logic (like TTL) you will quickly fry the logic gates.

The chip you found is the sort of thing you might find inside the TV or monitor it's self. If you were a TV designer doing one from scratch it is a chip you might consider.

The next step would be to trace out the circuit board and see where the wires all go. That will give you a good idea of what is what. After that its off to circuit design land to build a bunch of high voltage drivers and interface whatever you have to them. I'd bet the result will be a raster scan system that runs about 400 lines resolution. On a 20 year old CRT you may be able to read what ever it spend it's life displaying in the burn on the phosphor once you get a raster up.

Bob

ali6x944 · « **Reply #14 on:** February 18, 2016, 06:55:23 pm »

see the CRT:
https://drive.google.com/open?id=0B5vW-k7HbsL4bERFUnNRc2pCVEE
i also found amazingly 2 555 timers, i will try to reverse engineer it, i will post pics and values for all the parts soon...
thanks for explaining

ali6x944 · « **Reply #15 on:** August 21, 2016, 06:59:10 am »

Hi,
I think I found a similar crt made by motorola in 1981 but unlike mine it is a twelve inch crt but it has similar schematics and pin labling as mine so here it is:
https://drive.google.com/file/d/0B5vW-k7HbsL4TUFYQlVMOGZOOWs/view?usp=drivesdk

ali6x944 · « **Reply #16 on:** August 24, 2016, 05:54:13 am »

Help please

ali6x944 · « **Reply #17 on:** August 25, 2016, 04:44:40 am »

Anyone???

uncle_bob · « **Reply #18 on:** September 01, 2016, 03:19:28 pm »

Hi

If the manual applies to your set, you just hook it up like the manual shows. You put a NTSC video signal and TTL sync's into it and it runs.

Bob

philpem · « **Reply #19 on:** September 01, 2016, 08:29:57 pm »

Quote from: ali6x944 on August 21, 2016, 06:59:10 am

Hi,
I think I found a similar crt made by motorola in 1981 but unlike mine it is a twelve inch crt but it has similar schematics and pin labling as mine so here it is:
https://drive.google.com/file/d/0B5vW-k7HbsL4TUFYQlVMOGZOOWs/view?usp=drivesdk

Look at page 14 (and pin 17 too) of the PDF and there's a pinout for the edge connector. It looks like it more or less matches up, but the pin numbering you're using is backwards (you said +12V was on pin 4, Motorola put it on pin 7).

The high negative voltages are for the "remote brightness" pot -- which makes sense. You put a 100K pot on those three terminals so the user can control the brightness from the front panel.

Apply +12V and ground to power the thing up...

Now you've got three signals left --

- Horizontal drive (HSync) -- page 17 says this is TTL
- Vertical drive (VSync) -- page 17 says this is TTL
- Video -- this is probably analog, but the monitor may take TTL too

Chances are, you can probably run this thing from an NTSC or PAL output, if you hooked up a sync separator (LM1881 followed by something to split the composite sync into H and V).

ali6x944 · « **Reply #20 on:** September 02, 2016, 05:13:02 pm »

Thank you very much ...
You are the best guys I have known:-+
Thanks a lot for all the support

ali6x944 · « **Reply #21 on:** September 03, 2016, 05:12:13 pm »

Last question thuo...
Dose the 100k pot need to be high wattage one say a 1w or higher or I just could use ¼watt pot without releasing the magic smoke

??

amyk · « **Reply #22 on:** September 04, 2016, 01:11:05 am »

Ohm's Law...

ali6x944 · « **Reply #23 on:** September 04, 2016, 05:20:01 am »

Oh god, I totally forgot thanx m8

uncle_bob · « **Reply #24 on:** September 04, 2016, 10:10:50 pm »

Quote from: ali6x944 on September 03, 2016, 05:12:13 pm

Last question thuo...
Dose the 100k pot need to be high wattage one say a 1w or higher or I just could use ¼watt pot without releasing the magic smoke ??

Hi

P = E^2/R

If E = 100, then E^2 = 10,000

If the pot is 100K and the supply is 100V, you are fine with a 1/10 W pot. The 1/4 W version would be a well derated part.

Bob


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Author Topic: how to drive CRT model MD1000-390? (Read 6481 times)

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