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Type: Posts; User: Dwight Elvey

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1. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### I don't think the count is getting far enough to...

I don't think the count is getting far enough to cause D8 pin 3 to do anything. I just don't think that path could do it at that time. I do think the problem is in that area. It is causing the...
2. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### It think it is E8 or E5 is failing. I'm thinking...

It think it is E8 or E5 is failing. I'm thinking E5 first then E8. Here is where a faster scope would be helpful. I has to be the feedback from D8 pin 6. Because of the shortness of the clocks, it is...
3. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### Ok, I just did some calculations. I think the...

Ok, I just did some calculations. I think the problem is A1. Check it agian, I don't think it is running. That would explain the 448Hz. It should slow the high order counts down by 8. It is reaching...
4. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### How about D7 outputs with C6 p3 grounded???...

How about D7 outputs with C6 p3 grounded???
Dwight
5. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### Hi Dave We are making progress. I think it is...

Hi Dave
We are making progress. I think it is mostly corroded pins that have gone open. There were a number of broken things and we are getting close. We were missing a clock and got that fixed....
6. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### Better still, 1000000 divided by 488.2 is 2048.3....

Better still, 1000000 divided by 488.2 is 2048.3. 2048 is a nice power of 2. E8 pin 6 looks at the high order counts. It is a likely suspect. It would clearly cause funny vertical.
After you do the...
7. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### 488 Hz on the video is not to friendly for the...

488 Hz on the video is not to friendly for the monitor. Don't run the monitor long like that. I think that explains the strange display.
It is not doing the full count for the vertical output. That...
8. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### That is a weird display. Are you sure you didn't...

That is a weird display. Are you sure you didn't rotate the yoke on the tube?
Anyway we have more checking to do in the video driver.
Can you look at the various Q outputs of D6 and D7 with your...
9. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### Most of those older scopes are 10MHz or less. The...

Most of those older scopes are 10MHz or less. The one your looking at looks to be a good scope.

That is curious as E6 should have no effect on A1 running. A1 is the row counter for the characters....
10. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### Ok, this is what I was expecting if the counters...

Ok, this is what I was expecting if the counters are not working. I wanted to remove any interference from the horizontal. Normally the horizontal reloads the counters on retrace for the start of the...
11. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### Opps! I thought your stuff was socketed. I'd...

Opps! I thought your stuff was socketed.
I'd like to do a little more before we unsolder stuff. Unsoldering can damage the board.
We can run a little experiment.
I'd like to disable the...
12. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### 10Mhz means analog sine wave of 10MHz will be...

10Mhz means analog sine wave of 10MHz will be reduced by 3 db. It will have a difficult time looking at a digital pulse signal of 60 ns. 20 or 30 MHz scope is about the minimum. Also, if it is a...
13. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### Please don't replace random chips. Earlier, when...

Earlier, when we were trying to get a clock from C8 pin 3. We ran an experiment to get a clock to the D flipflop. I believe you replaced C8, restoring that clock....
14. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### We know the horizontal is working. The vertical...

We know the horizontal is working. The vertical is more complicated.
What does D6 pin 5 and pin 12 look like?
Dwight
15. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### Another good place to look is at E8-6. This is...

Another good place to look is at E8-6. This is part of the end of page count. It should create a nice pulse at the vertical rate. It doesn't check the rest of the path to the vertical out but still...

by Dwight Elvey
Replies
52
Views
2,747

### I meant super glue but I suppose hot glue would...

I meant super glue but I suppose hot glue would work. I usually have a piece of blue tape to hold them and then once in place, I have long tweezers to pull the tape out.
Dwight

by Dwight Elvey
Replies
52
Views
2,747

### hot glue. Make sure it has dried before sticking...

hot glue.
Make sure it has dried before sticking the screws in or you may never get them out again. You can get accelerator from hobby shops but that stuff stains. I usually breathe my breath on it...
18. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### These may be problems in the monitor. First...

These may be problems in the monitor.
First thing to do is check with your scope the horizontal and vertical signal, J7-5 and J7-3.
At least things are becoming more alive. I hope we don't have to...

by Dwight Elvey
Replies
52
Views
2,747

### Come back once you have the system and we can...

Come back once you have the system and we can take a look at things. The trickiest part is taking the front panel apart without loosing the spacers. It looks cool but it was not designed for quick...

by Dwight Elvey
Replies
52
Views
2,747

### I sent you a PM. Anyway, I do online help for a...

I sent you a PM. Anyway, I do online help for a hobby. Here, it also helps others as well, not just you. Besides I don't think you'd be happy with my minimum and hourly rate.
21. ## Thread: Spindle won't run when 5.1/4 floppy Panasonic JU-475-3A11 is accessed

by Dwight Elvey
Replies
30
Views
326

### I also refuse to use FB as well as linkedin. They...

I also refuse to use FB as well as linkedin. They are both data rapers. Just logging out right ways has no effect on what they sell about you. I grudgingly use google search.
Dwight

by Dwight Elvey
Replies
40
Views
765

### One of the issue with expanding the size of your...

One of the issue with expanding the size of your loops with loops or NOPs is that you run out of music for your song.
You should be able to make a single loop so everything.
I've not seen a easy...
23. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### I recommend buying at least a 100MHz analog...

I recommend buying at least a 100MHz analog scope. If you do buy a digital scope, get one with a large screen buffer. It is a great addition to a digital scope that makes it worth all the other...
24. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### That is OK I understand how it is suppose to...

That is OK I understand how it is suppose to work.
Someplace between where the character/graphic clock should be created and that last point we measured, something is getting lost.
C8 pin 3 creates...
25. ## Thread: Pet 2001 chiclet display problem

by Dwight Elvey
Replies
77
Views
884

### I'm trying to find a place that your scope can...

I'm trying to find a place that your scope can see that narrows things down. A lot of the signals are high speed single pulses that are of interest but like the signal at C6 pin 9, just beyond what...
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