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blog:x68_pro_fault [2020/08/07 09:20] – [Okay, lets replace ALL capacitors] johnblog:x68_pro_fault [2021/02/24 14:03] (current) – [The Final Curtain] john
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 ---- ----
  
-=== Capacitor List === 
  
-Following the visual check, I made a list of all the (electrolytic) capacitors on the boards: 
- 
-^ Number ^ Board ^ Capacitance ^ Voltage ^ Temperature Rating ^ Notes ^ 
-| C1 | Main  |0.47uf |50v |85c | |  
-| C5 | Main  |220uf |6.3v |85c | |  
-| C12 | Main  |330uf |6.3v |85c | |  
-| C13 | Main  |100uf |16v |85c | |  
-| C15 | Main  |330uf |16v |85c | |  
-| C16 | Main  |470uf |6.3v |85c | |  
-| C38 | Main  |4.7uf |50v |85c | |  
-| C39 | Main  |4.7uf |50v |85c | |  
-| C40 | Main  |470uf |10v |85c | |  
-| C41 | Main  |470uf |10v |85c | |  
-| C43 | Main  |470uf |10v |85c | |  
-| C44 | Main  |3300uf |6.3v |85c |Large cap near rear IO panel|  
-| C47 | Main  |4.7uf |50v |85c | |  
-| C48 | Main  |4.7uf |50v |85c | |  
-| C49 | Main  |4.7uf |50v |85c | | 
-| C50 | Main  |100uf |10v |85c | | 
-| C56 | Main  |33uf  |10v |85c | | 
-| C201 | Sub   |100uf |6.3v |85c | |  
-| C202 | Sub   |100uf |10v |85c | |  
-| C203 | Sub   |100uf |10v |85c | |  
-| C204 | Sub   |330uf |6.3v |85c | |  
-| C205 | Sub   |47uf |16v |85c | | 
-| C207   | Sub   |10uf |16v |85c | |  
-| C210 | Sub   |47uf |16v |85c | | 
-| C211   | Sub   |100uf |6.3v|85c | |  
-| C213 | Sub   |4.7uf |50v |85c | |  
-| C214 | Sub   |47uf |16v |85c | |  
-| C215 | Sub   |47uf |16v |85c | |  
-| C218 | Sub   |100uf |6.3v |85c | |  
-| C220 | Sub   |4.7uf |50v |85c | |  
-| C221 | Sub   |4.7uf |50v |85c | |  
-| C222 | Sub   |47uf |16v |85c | |  
-| C223 | Sub   |330uf |6.3v |85c | |  
-| C224 | Sub   |100uf |16v |85c | |  
-| C225 | Sub   |100uf |6.3v |85c | |  
-| C226 | Sub   |100uf |16v |85c | |  
-| c227 | Sub   |0.47uf |50v |85c | |  
-| C231 | Sub   |0.47uf |50v |85c | |  
-| C232 | Sub   |1uf |50v |85c | |  
-| C233 | Sub   |0.47uf |50v |85c | |  
-| C234 | Sub   |100uf |10v |85c | |  
-| C238 | Sub   |0.47uf |50v |85c | |  
-| C239 | Sub   |0.47uf |50v |85c | | 
-| C240 | Sub   |330uf |6.3v |85c | | 
-| C241 | Sub   |100uf |16v |85c | Failed |  
-| C242 | Sub   |330uf |6.3v |85c | |  
-| C243 | Sub   |100uf |16v |85c | Failed | 
-| C244 | Sub   |330uf |16v |85c | | 
-| C249   | Sub   |1uf |50v |85c | | 
-| C251   | Sub   |22uf |16v |85c | | 
-| C255 | Sub   |4.7uf |50v |85c | |  
-| C256 | Sub   |47uf |16v |85c | |  
-| C262 | Sub   |330uf |16v |85c | |  
-| R221 | Sub   |47uf |16v |85c | Cant make the number out, but its next to R221.| 
- 
-Yes, that's right; there are more than **50** electrolytic capacitors on the motherboard. 
- 
-Quantities: 
- 
-   * **6x** 0.47uF, 50v 
-   * **9x** 4.7uF, 50v 
-   * **2x** 1uF, 50v 
-   * **1x** 10uF, 16v 
-   * **1x** 22uF, 16v 
-   * **1x** 33uF, 10v 
-   * **7x** 47uF, 16v 
-   * **3x** 100uF, 6.3v 
-   * **4x** 100uF, 10v 
-   * **5x** 100uF, 16v 
-   * **1x** 220uF, 6.3v 
-   * **5x** 330uF, 6.3v 
-   * **3x** 330uF, 16v 
-   * **1x** 470uF, 6.3v 
-   * **3x** 470uF, 10v 
-   * **1x** 3300uF, 6.3v 
- 
----- 
  
 === Next Steps === === Next Steps ===
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 **[Update - August 3rd 2020]** - Since there seems to be ongoing issues with the system, the only thing that makes sense to do at this point is to replace **all** capacitors. **[Update - August 3rd 2020]** - Since there seems to be ongoing issues with the system, the only thing that makes sense to do at this point is to replace **all** capacitors.
  
-For the full list of caps on the main board, refer to the [[blog:x68_pro_fault#Capacitor_List|table above]]+For the full list of caps on the main board, refer to the my [[blog:x68000_pro_cap_list|X68000 Pro]] capacitor list page.
  
 ---- ----
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    * **2x** 22uF, 25v    * **2x** 22uF, 25v
    * **2x** 100uF, 10v    * **2x** 100uF, 10v
 +
 +{{:blog:img_1716.jpg?350|}} - Drive control board; C101, C107 replaced (make sure you bend or fit a low profile caps)
  
 ---- ----
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 Not sure whether any of these will need replacing, but here's a list of all the discrete logic components on the board (excluding things like the sound chips, cpu, ram, video controller, etc): Not sure whether any of these will need replacing, but here's a list of all the discrete logic components on the board (excluding things like the sound chips, cpu, ram, video controller, etc):
  
-{{:blog:ic1-ic2-ic13.png?200|}}{{:blog:ic18-ic19.png?200|}}{{:blog:ic21-ic22.png?200|}}{{:blog:ic24.png?200|}}{{:blog:ic26-ic27.png?200|}}{{:blog:ic29-ic30-ic31.png?200|}}{{:blog:ic33-ic34-ic35.png?200|}}{{:blog:ic36-ic37-ic38-ic39-ic40-ic41.png?200|}}{{:blog:ic62-ic63-ic64-ic65-ic84-ic85-ic86-ic87.png?200|}}{{:blog:ic88-ic89-ic90-ic91.png?200|}}{{:blog:ic92-ic93-ic94.png?200|}}{{:blog:ic213-ic214-ic215.png?200|}}{{:blog:ic224-ic225-ic226-ic227-ic228-ic229-ic230-ic231-ic232-ic233.png?200|}}{{:blog:ic235-ic236-ic237-ic238.png?200|}}+   * [[blog:x68000_pro_ic_list|Sharp X68000 IC list]] 
 + 
 +===== Another Round of Testing ===== 
 + 
 +=== Audio Circuit Repair Test === 
 + 
 +Well the op-amp and amplifier IC replacement fixed the issue with no sound coming from the speaker unless you had your ear up against it: 
 + 
 +{{jPlayerPlaylist>blog:x68000_op-amp_repaired.mp3}} 
 + 
 +It's still not the greatest in the world, but it's fine for a tiny little 0.5w case speaker. 
 + 
 +---- 
 + 
 +=== Keyboard === 
 + 
 +Keyboard is still inactive. 
 + 
 +---- 
 + 
 +=== Joystick Ports === 
 + 
 +Tried an MSX compatible pad in both port 1 and port 2, it doesn't register in MotosThe game won't let you start. 
 + 
 +---- 
 + 
 +=== Floppy Drives === 
 + 
 +Floppy drive 0 still works fineFloppy drive 1 still spits the disk back out as soon as you've inserted it. 
 + 
 +---- 
 + 
 +=== Memory === 
 + 
 +The onboard 1MB, the additional 1MB from the IOData module and the extra memory on the XSIMM10ss card all test fine in memtest68k. 
 + 
 +---- 
 + 
 +=== Booting Human68k DOS === 
 + 
 +A Human68k dos boot disk still brings up the //"It was not possible to start the system, please reboot"// message. 
 + 
 +---- 
 + 
 +==== So What Now? ==== 
 + 
 +I'm out of ideas with the system now. I think there is quite likely some damage to one or more of the IC's on the boards, but where to start with that, I've no idea. I don't have a scope and I don't have an electronics background. 
 + 
 +**[Update September 2020]** So I bought a '__working__' X68000 Pro from Japan, planning to use most of the parts from it to make a fully working system... but upon arrival... well, [[blog:x68_pro_fault2|see for yourself]]. 
 + 
 +The plan now is to remove as much of the obviously unaffected components from the new 'donor' system as possible desoldering chips, if necessary and transplant them in to my 'mostly working' system that I've spent all of this effort on. 
 + 
 +Stay tuned, I'll be posting more progress below. 
 + 
 +====== The Final Curtain ====== 
 + 
 +**[Update 24/02/2021]** 
 + 
 +After spending months more trying to get the system working I only just managed to get it booting a Human68k floppy despite desoldering the last remaining surface mount chips from the IO sub board. Keyboard still didn't work, joystick still didn't work - making it completely unusable. 
 + 
 +Tracing signals and low level logic debugging is not what I want to get in to, so it's time to draw a line under all of this and move on. Perhaps someone more adept than myself could get this running again. But that's it for me; I need to move on. 
 + 
 +It's pretty sad to say that //were it not for the incorrect PSU wiring diagram//, this would have been an easy job and I'd have had months of fun playing with the system by now.
  • blog/x68_pro_fault.1596788456.txt.gz
  • Last modified: 2020/08/07 09:20
  • by john