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1982 Kaypro II no display

That's looking more like a bad video output/high-voltage board. Maybe others more-experienced with video can tell. Looks to me like you don't actually have a true raster image on the CRT. If you are, you'll see a faint pattern of horizontal lines (with brightness turned up), and possibly retrace lines, something reminiscent of this:
1645579733547.png
Of course, the lines will be much closer together as there are several hundred of them.

The aurora in your video in the lower left corner looks more, to me, like the electron beam never making it through it's normal scan - i.e. stuck in the corner.
 
Could that possibly be fixed by replacing the components on the output board, or this tube toast?
 
Someone with video/HV experience would need to answer that. I suspect one (or more) of the transistors on the HV circuitry board has failed, or something like the flyback transformer. I'm just repeating buzzwords now, though. Need an expert in that field.
 
Someone with video/HV experience would need to answer that. I suspect one (or more) of the transistors on the HV circuitry board has failed, or something like the flyback transformer. I'm just repeating buzzwords now, though. Need an expert in that field.
ah ok cool, i'll pull the board out and give it a good look over. regarding what i mentioned about 2114 srams for the video display, is it normal for them to run quite warm? They get up to ~50c or so after about 10 minutes
 
ah ok cool, i'll pull the board out and give it a good look over. regarding what i mentioned about 2114 srams for the video display, is it normal for them to run quite warm? They get up to ~50c or so after about 10 minutes
I'm not sure what's normal, but those RAMs are being accessed continuously so they may heat up. I'm not sure what's normal for those, either - some of those older RAM chips did run warm. My 2X contains 6116 chips which are CMOS and probably run a lot cooler.
 
ah ok. i may order some more just to be on the safe side. I did have a thought to maybe rule some things out too. looking at the pinout of the connector to the crt and the tech specs- it consists of 3 pins: vert sync, horiz sync, and video. From what i can tell it outputs a pretty standard 15khz horizontal and 60hz vertical signal. In theory, could i hook it up something like a gbs8200 via the vga port?

Also, if there was an issue with the crt itself, wouldn't i not be able to see the garbage on the screen i mentioned prior? That should indicate the crt itself is able to propery draw things on screen, no?
 
ah ok. i may order some more just to be on the safe side. I did have a thought to maybe rule some things out too. looking at the pinout of the connector to the crt and the tech specs- it consists of 3 pins: vert sync, horiz sync, and video. From what i can tell it outputs a pretty standard 15khz horizontal and 60hz vertical signal. In theory, could i hook it up something like a gbs8200 via the vga port?

Also, if there was an issue with the crt itself, wouldn't i not be able to see the garbage on the screen i mentioned prior? That should indicate the crt itself is able to propery draw things on screen, no?
I was wondering the same thing - could you connect the video to a more-modern display. I don't know enough to know what's possible in that area. I have heard about various devices that are designed to convert legacy video signals.

I was curious about what you said previously about seeing garbage characters displayed briefly. I wonder if the video could be operational for the first few frames after power-up, and then whatever is broken fails and the electron beam is no longer scanning correctly.
 
It looks like the beam on the CRT is below the edge of the tube which is quite weird. Most of the times when the vertical deflection fails the beam is centered.
If you type something in and press Return/Enter a few times, the text does not scroll up ?

You can also try adjusting the vertical height potmeter on the CRT board and see if that brings the text into the visible area.
Warning! there is high voltage nearby the output transformer and the potmeters are (often) below the CRT.
If in doubt, adjust the potmeter a tiny bit left/right while the system is off and switch on to see the effect.
 
It looks like the beam on the CRT is below the edge of the tube which is quite weird. Most of the times when the vertical deflection fails the beam is centered.
If you type something in and press Return/Enter a few times, the text does not scroll up ?

You can also try adjusting the vertical height potmeter on the CRT board and see if that brings the text into the visible area.
Warning! there is high voltage nearby the output transformer and the potmeters are (often) below the CRT.
If in doubt, adjust the potmeter a tiny bit left/right while the system is off and switch on to see the effect.
I'll try messing with it when i get off work today. when i type things in the aurora seems to widen, and pressing enter a few times it seems to get brighter then go dark until i clear the screen and try again
 
Some joker didn't put a big magnet in the bottom of the case did they? Or the yoke really, really misaligned?
Don't see any magnets anywhere near the tube. May be a dumb idea, but if i run a magnet across it could that try to move the image up? Regarding the yoke adjustment, it's possible, what's the best way to go about adjusting it?
 
We might already be past this point, but especially if your phone has slo-mo it might be good to get a video clip of the screen during power-on. Might give some clues as to what could be going on (i.e. does the raster display properly for a few seconds, then collapse? etc...)
 
Just tried it on an iphone and image was too faint too really see anyththing with slomo on. I did see the usual flickering when the refresh rate doesn't sync up with the camera and it looked to be going from top to bottom when i typed a bunch of stuff then hit enter a few times until the screen was mostly illuminated. Also, i tinkered with the vertical height and it didn't look to make much difference. even with more radical adjustments in both directions it did seem to have much effect
 
My guess is that the vertical deflection circuit is broken somehow, could be as simple as a dried out capacitor of more complex like failed semiconductors.
Alas I did not find schematics of the monitor boards used in the Kaypro.
The service manual mentions three manufacturers of the CRT assemblies: Dotronix, Elston and Toshiba.
 
I agree with gertk, as it seems to be the Vertical deflection circuit that isn't working. I wish I had my TV
manual to refer to about the circuits running the Yoke, but I don't.

The Schematic shows the Yoke's wiring as follows. I've traced the LOW side of both the the common rail.
Yoke S103-1 Horiz Yoke - Switched High/Low
Yoke S103-2 Horiz Yoke - LOW
Yoke S103-3 Vertical Yoke - LOW
Yoke S103-4 Vertical Yoke - Switched High/Low

Can you tell if your Video board is one of the phot's attached?

As I've previously posted I do have a schematic for the Elston Video Board.

Larry
 

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sorry for the late reply, but my board looks to be the toshiba. the crt board looks identical and there's a sticker on the tube that says toshiba as well
 
The Toshiba should still have signals to the Vertical and Horizontal Coil's of the Yoke.

The Elston has:
Code:
Pin 01 = Horizontal GND
Pin 02 =
Pin 03 =
Pin 04 =
Pin 05 =
Pin 06 = Horizontal Drive (High Pulse)
Pin 07 = +12 VDC
Pin 08 = Video
Pin 09 = Vertical Sync (Low Pulse)
Pin 10 = Video & Vertical GND


Yoke S103-1 Horiz Yoke - Switched High/Low
Yoke S103-2 Horiz Yoke - LOW
Yoke S103-3 Vertical Yoke - LOW
Yoke S103-4 Vertical Yoke - Switched High/Low

I got the above pinout from the attached Schematic. The Yoke of your Kaypro should also be very similar in design.

Larry
 
Since the beam is deflected to the bottom side there must be some weird DC current flow into the vertical yoke.
The DC decoupling is done by C310.
Try measuring C310 for a short, the TDA1170S might be running hot also then (or maybe is damaged already)
 
also @bifo86 i used a regular phone handset cable on my kaypro 2 and it seems to work fine. I read that depending on the quality it may not always work quite right but it's wired the same
The cable is fine (original) but the plastic phone plug itself managed to crack a few years ago and it won't retain the cable. I was wondering if anyone had had a similar problem and knew of a preferred replacement that won't look like a sad kludge.
 
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