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STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 14:34
by Steve
Hi guys,
Just doing some servicing on a customers STe, here is my work on it...
Board images here
* Clean disk drive
* Apply motherboard bus resistor fixes
* Replace a few important capacitors, like reset circuit
* Add STe ghosting fix capacitor
* Replace mouse/joystick port
* clean/resolder video port
* General machine clean
The beginning...
1. begin.jpg
What do we have missing here?
2. oops what is missing.jpg
Bit rusty on the shield
3. rusty shield.jpg
Floppy needs a good clean and service!
4. dirty floppy.jpg
Time for a thorough clean
8. cleaning floppy.jpg
9. clean floppy.jpg
Let's replace the drive lube
5. old lube.jpg
10. new lube.jpg
Let's also re-cap the floppy
6. recap floppy 1.jpg
7. recap floppy 2.jpg
12. recap floppy motor.jpg
Shame, after all that the floppy is still having issues!
11. floppy still bad.jpg
The floppy heads are physically touching/scratching the disk, you can see the black mark worn on the head. The floppy drive is TOAST. So we are going to go for a FlashFloppy instead!
13. chewing disks.jpg
Re: STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 14:34
by Steve
Time to re-cap the PSU! It is a DSP-508a
18. psu before recap.jpg
After the recap, looking good!
19. psu after recap.jpg
Time to test the voltage output under load!
21. test 5v.jpg
20. test 12v.jpg
Re: STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 14:37
by Steve
Time to do some work on the motherboard, first the reset circuit and 470uf capacitor
15. re-cap reset circuit and 470uf.jpg
New 4700uf capacitor
PXL_20211014_183256157.jpg
Now time to swap out the 10k SILs for 2.2k
16. old sils gone.jpg
17. new sils in.jpg
Let's add the video ghosting fix while we're here
14. video ghosting fix.jpg
Re: STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 14:37
by Steve
Time for some keyboard work
22. time to fix keyboard.jpg
Quite a bit of grunge to clean
23. a bit grungy.jpg
24. more grunge.jpg
Looks like the port area has a missing pad and broken trace
25. missing pcb pad trace.jpg
28. new port soldered and trace patched.jpg
Guess who put it back together, all 30 or so screws, then realised he forgot to reflow the solder on the mouse port... Well, it's done now.
PXL_20211014_182220876.jpg
30. new port.jpg
Let's give the keyboard and casing a good wash
26. time for a wash.jpg
27. wash case.jpg
Board nice and clean now
29. clean board.jpg
Those rubber feet look melted! Let's replace them
31. old feet.jpg
32. new feet.jpg
After everything I've done so far does everything still work I wonder? Let's do a quick test :)
33. does it still work.jpg
Re: STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 14:40
by Steve
New HC type CPU
New Hotel drive
PXL_20211017_133852221.jpg
PXL_20211017_133858595.jpg
Re: STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 15:08
by PhilC
@Steve what are you using for replacement feet?
repair looks good btw.
Re: STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 15:23
by rubber_jonnie
What's going on with that FDD? I've never seen one with all the motor coils exposed like that, looks like it's missing the rotor or something.
Re: STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 15:24
by Steve
rubber_jonnie wrote: 14 Oct 2021 15:23
What's going on with that FDD? I've never seen one with all the motor coils exposed like that, looks like it's missing the rotor or something.
They're not normally exposed, I was just replacing the capacitor which needed the cover taking off.
Re: STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 15:34
by rubber_jonnie
Steve wrote: 14 Oct 2021 15:24
rubber_jonnie wrote: 14 Oct 2021 15:23
What's going on with that FDD? I've never seen one with all the motor coils exposed like that, looks like it's missing the rotor or something.
They're not normally exposed, I was just replacing the capacitor which needed the cover taking off.
I get that, I'm used to seeing this:
IMG_20211014_152829.jpg
With the coils under the rotor (Silver disc) so that looks really strange to me. How is the spindle driven?
By cover did you mean the FDD case or the silver disk?
I'm just curious is all :)
Re: STe service blog / CA300779-001 Rev 5.1
Posted: 14 Oct 2021 15:39
by Steve