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Just won a 4016... Where to find help on monitor troubleshooting?

dabone

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I just got home and found I had won a 4016 that has the following description.

THIS UNIT BEEPS WHEN TURNED ON BUT SCREEN IS BLANK
SOLD FOR PARTS AS IS


What should I start with, I don't have the unit yet, I guess I should wait till it gets here to check for high voltage in the display first, but I love trying to figure it out even before I see it.

If I have high voltage, should I go ahead and try replacing caps in the monitor or order in a crtc?

I've got a scope, but no spare pet parts for this board. (I've got a 2001 with the original release 6550/6540 motherboard, no crtc).
I also can't wait to try the petvet out on it.

Later,
dabone
 

bitfixer

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Hi dabone,

I have an 8032 that I repaired a while back that had very similar symptoms.
At first it did nothing at all, and it turned out to be a bad ROM.
After that it beeped and nothing appeared on the screen. That problem turned out to be a bad CRTC chip.
I don't know if the 4016 monitor can be driven by a 2001 motherboard, but if so you could try that to see if the monitor itself is bad or not.
If the monitor itself works then I would suspect the CRTC.
 

magicappstore

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Hi,

I had the same problem with a 4032 I got, and the problem turned out to be the CRT chip which, luckily is the same as the one used in my BBC Micro, so after a quick swap it was working!
 

dabone

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Anyone in the US have a CRTC chip for sale?. I know Unicorn Electronics has them, but they have a 25.00 min order + shipping.

Later,
daboen
 

bitfixer

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hey dabone,

I think I have a spare which I ordered to fix that 8032 a while back. If I have it, I can send it to you. Also I may be ordering some stuff from Unicorn in the next week or so, and could include a CRTC in the mix if you like. Just send me a PM if interested.
 

dabone

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Wouldn't this be a perfect test for the petvet?
First test is plug it in, start the terminal and dump the screen.
I can then test blind loads and commands, using the petvet to check output.

Later,
dabone
 

MikeS

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I'd check the video cable and connectors first (both ends) and check if any or all of the three sync and video signals are present.

Is the CRT filament lit?
 

bitfixer

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Wouldn't this be a perfect test for the petvet?
First test is plug it in, start the terminal and dump the screen.
I can then test blind loads and commands, using the petvet to check output.

Later,
dabone

That's true - assuming only the CRTC was bad, you should be able to start it up and run blind commands as you said.
Might need a different ROM set to run a 40-column basic 4 CRTC pet. When I get a chance I can add that as a setting for the PETvet.
 

dabone

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Ok, I got the unit it today, and when I power it up I get the chirp, but no video as stated. I also have no high voltage that I can hear or feel on the monitor.
(It does have neck glow, but doesn't have that hum of high voltage, or the static discharge when powered down.)

In the case of a good monitor/bad crtc, do you still get high voltage? or is it lacking without the sweeps?

Later,
dabone
 

dabone

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Ok, why is it every time I bring a pet home it catches on FIRE????
I was playing with the pet and was using the scope to look for output on the video connector and found none, then I decided to put a
welte's Universal ram/rom board in it. First time I turned it on after that I got nothing, but I shut down again and selected a different rom bank and got the chirp again. (Still no video). I then powered if off again, and it wouldn't turn back on. I left the switch on for a few while I was checking voltages, and I had No +5, and then I hear a sizzling sound coming from the power supply. The ac input filter burned up (The connector where you plug in the power cable). Lots of smoke and my office stinks now.

I yanked the power jack out and straight wired a power cord at the moment, put the unit will not come up anymore.
-----If I have the motherboard plugged in it pops the fuse, and when I try to measure the ac voltages from the power supply, I'm not getting reading that I can
-----understand. Does anyone have the J8 Ac power input pinout?

Ok, I have ac power, the cord I grafted on was bad. I still have a mb short problem that is popping the fuse.

I removed cr2 and cr4 and checked for shorts. They aren't shorted, but they read a little different than each other.

Later,
dabone
 
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dabone

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Ok, new update. I really really really want to slap the person at Commodore that decided it was ok to rivet in the frigging voltage regulators.
I've replaced the power input jack/filter, and the 5V regulator, and I'm getting my startup chirp again. Still no video.

My question again is, will a pet with a defective crtc chip still generate high voltage sweep at the monitor?

Later,
dabone
 

dabone

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No, it won't. HSYNC drives the charge pump for the high voltages.

Well that goes with what else I found, I grabbed the schematics and went backwards from the connector, someone a long time ago had removed the 7486 from the motherboard and put it in a horrible quality blue socket, and the chip had oxidized pins, so I replaced the socket and 7486 and I had vertical signal, but still nothing on hsync. So going back to the 6545, there was no voltage of any kind on pin 39, but I had activity on pin 40.

So I did the safe thing and cut all the pins off the 6545 and installed a socket, and there it waits untill I get a 6545. I also destroyed the cpu socket by accident last night trying to plug in my petvet. (I didn't look at the cpu socket and notice it was a closed type where you couldn't see the contacts, and the petvet prototype had header pins that deformed the socket.The socket that gubbish shipped it with was damaged and I forgot to replace it.) Oops.

Later,
dabone
 
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dabone

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Ok, got a 6545 in today, opened the pet, installed it and Bingo! I have a screen!
(I had a VERY tall screen to begin with.)

After adjusting the vertical height, and turning the yolk a bit (It was crooked and leaning left), the 4016 lives again!
Now I just wish my favorite version of Space Invaders worked with it. It doesn't seem to work with basic 4, and most likely won't work on a crtc pet anyway.

(Link to the version I'm talking about).

http://www.youtube.com/watch?v=bNAS-fJpKaE

I did get No pets allowed to mostly run by using my Nicolas Welte ram/rom board and selecting 50hz roms.

Thanks gubbish!

Later,
dabone
 
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