Thread
Macintosh Plus CRT issue
this was previously discussed here:
viewtopic.php?f=4&t=19456&start=25#p188369
However it wasn't resolved. Now I don't know much about what cap goes where and what not but I thought I would get a video so you guys had a better Idea of the problem, and maybe someone could tell CC_333 their ideas on it?
The video (youtube)
http://www.youtube.com/watch?v=5dP5yaTHnGk
Thanks!
)
viewtopic.php?f=4&t=19456&start=25#p188369
However it wasn't resolved. Now I don't know much about what cap goes where and what not but I thought I would get a video so you guys had a better Idea of the problem, and maybe someone could tell CC_333 their ideas on it?
The video (youtube)
http://www.youtube.com/watch?v=5dP5yaTHnGk
Thanks!
)
That image is very much too biggiesized, to the point of not working correctly, IMHO.
It's supposed to be tiny! :
It's supposed to be tiny! :
LOL. I had to zoom in, to see it
Time for me to chime in!
jt: I adjusted the display to normal, WYSIWYG specifications, according to MRUS (7.11" x 4.75").
There were a few more items I suspected as being the cause of the problem, but I ran out time (I had to send it to markyb), so I couldn't investigate further.
It seems he's picking up where I left off.
I'll try to help where I can.
c
jt: I adjusted the display to normal, WYSIWYG specifications, according to MRUS (7.11" x 4.75").
There were a few more items I suspected as being the cause of the problem, but I ran out time (I had to send it to markyb), so I couldn't investigate further.
It seems he's picking up where I left off.
I'll try to help where I can.
c
raster distortion/blooming is the result of low B+
What can cause low B+?
The re-cap was theoretically supposed to resolve that, but it didn't.
Why?
c
The re-cap was theoretically supposed to resolve that, but it didn't.
Why?
c
Any number of things. I'd first start by checking the voltages out of the power supply. Also check carefully for bad solder joints in the monitor circuitry, especially in the horizontal deflection section. Low anode voltage (the high voltage to the CRT) will cause the picture to expand. The HV circuit is part of the horizontal deflection circuit, and B+ in the case of these monitors is 12V IIRC.
Does it not just need adjustment (balance, pincusion, or trapezoid)?
onlyonemac: There are some square pieces of material (ferrous/magnetic, possibly) which control the shape of the picture. I did my best to equalize these before selling the machine to markyb, but they seem to be unrelated to the current problem.
There were several capacitors I didn't replace (I sort of wish I did). Some of those could be causing the screen to go weird.
c
There were several capacitors I didn't replace (I sort of wish I did). Some of those could be causing the screen to go weird.
c