Thank you, I already fixed the vertical issue. It was a bad tantalum cap on Vertical Height line.
Now I have new issue, when the monitor gets hot from running about 20minute, it will lose the focus and then shut itself down.
I guess need to check with the 100v or 70v rail when it happen, but...
Seems that there's still some issue on the power supply side, I assume that it trigger the protection circuit because of it goes under volt instead of over voltage
Thank you.
But now I found some other problem, if it running for some time (around 15m). It will shutting down and producing some noise.
I need to pull the power out from the main, and wait for several second before I turn it on again.
Is there any thermal protection for the monitor?
Finally I fixed it!!
The issue was on the vertical height line.
It has a tantalum (1uf/35v) which is dead.
Since I don't have any tantalums, I replaced with electrolytes type
Hi this is my output of LA7824 which generate a signal but it seems too weak and noisy compared to the input signal on PIN 14.
I already swapped the chip but the result is the same. Wondering it was some passive components around it.
Can you share which type of monitor of yours? Or better can you share the schematics and point which resistor?
I'm CRT newbie, but maybe I can pinpoint mine based on yours
I see, did you also recaps the neckboard?
Yes I reflow the DY and all other "Hot" pins, but currently still stuck on the same issue
:LOL:
How about yours?
Yes I'm having the same board, and I'm just realized about that component numbering LOL 😂
I'm also CRT newbies, so I tried to check the components one by one carefully. Without a schematics it would be slow, but AI also helped me through.
Do you still have the monitor?
Did you fully recaps...
Haha so sad, I'm kinda having the same problem as yours. But mine the vertical is fully collapsed, only showing the horizontal line.
Still investigating what could be wrong.
Last time I tried to tapped the input of TA8403K with my finger, the vertical is wobble, seems the power IC is working...
Hi, sorry for commenting on the old post.
I'm having the same issue, the vertical collapse.
All voltages checked okay.
Already recaps the board, tried to replace the D2906 and LA7824 but still the same.
Need any clue.
Also I'm wondering the value of Q501 transistor, mine was faded away.
Thank you
Hello, thanks for replying.
I'm finally able to read and write using the drive.
I don't know exactly why. Previously, I'm trying to read a disk that has been written from WinImage. This would not work when I'm using floppy internal cable, but would work when using cable from DB9 connector. But...
Hello, I'm just finished recapping my old Macintosh Classic II and now toward fixing the internal floppy.
The internal floppy would boot into a happy mac logo but then eject the floppy.
But this would not happen when I'm using the same floppy but used as external floppy (using cable from DB19)...
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