ATARI STE video error

[AtariPope]

Hi all,

I have a problem with my STE, it is the model that has empty space left to the CPU and has combined shifter/blitter c301712-001.
The PSU got bad and the video does what you see in the attachement. Occasiohnally I see the desktop. Can someone advise what is the part that got bad? 32Mhz Crystal? c301712-001 ? capacitors? Should I do a full recap?



Any help is appreciated

[exxos]

Reset button stuck closed ? Has the monitor and/or scan doubler ever worked on a Atari ST/E ? Checked the monitor cable ? Checked the solder joints on the RGB port ? Any floppy drive activity after power up ? Re-seated and cleaned all the chips you can remove ?

[AtariPope]

Reset button stuck closed ? Has the monitor and/or scan doubler ever worked on a Atari ST/E ? Checked the monitor cable ? Checked the solder joints on the RGB port ? Any floppy drive activity after power up ? Re-seated and cleaned all the chips you can remove ?

Hi there. Thanks for the quick response. The button seems ok as when I press it it does a restart and presents again the series of bombs. Atari was working perfectly with this cable on this monitor 2 hours before the video, I managed to see also the desktop but degraded more to only bombs. The video uploaded is with another working PSU. CPU, Shifter and roms where removed and checked with chips from another STE still the same. Checked with two cables. No floppy activity on boot. I measured all crystals and they have nominal frequency except the 32Mhz. When I flipped the board I noticed that one leg from R130 (32MHz) was long enough touching C128 leg (GND) . I believe this is when all started because it happened after I installed the new PSU (must have pressed the board enough to bend the long legs). I trimmed the legs to disengage them and when I measure with Oscilloscope that leg of Q104 & R130 has nothing close to a 32MHz. Any thoughts?

---UPDATE--- After changing the Q104 transistor that was also shorted, I see 10.7MHz (one third of the nominal)... 3rd overtone?

[Cyprian]

besides tons of bombs, it looks like 50hz vs 60Hz issue

[AtariPope]

Changed the Crystal and now I boot but the video is still weird.

[AtariPope]

SOLVED. it is the MC1337 that broke and was sending crap csync to Q404. lifted the resistor that feeds the transistor and pulled a plug directly from U211 pin6. the STEs that do not have the modulator take it from there.

[exxos]