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Post by robin36mac on Mar 20, 2019 6:02:08 GMT -5
That fried one here is SR2 ; R208 is the smaller green one.
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Post by Decibel on Mar 20, 2019 6:08:44 GMT -5
That fried one here is SR2 ; R208 is the smaller green one. Ok. We tried with two different convergence boards. Same resistor smoked at Stefano's home and original convergence board. Today this SR2 smoked in my home with another board (older version, short pcb). |
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Post by Decibel on Mar 20, 2019 8:15:40 GMT -5
There were a modification done on the schematics, the resistor and the capacitor are well listed, as R410 and C410 and as "Manual" instead of SMD. In previous revision, they were implemented in the PCB, then removed from the schematics. Older : After : It'spossible these compnents needed to be even closer of each other. So as as they are well listed in the partlist, that's well intended, and should be redone that way. Robin Can you upload the complete schematic in the section "Service Manuals" of this forum? Thank you |
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Post by robin36mac on Mar 20, 2019 8:16:57 GMT -5
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Post by Decibel on Mar 20, 2019 9:01:14 GMT -5
I found the old schematic sheet in the service. Where is the new one?
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Post by robin36mac on Mar 20, 2019 9:05:12 GMT -5
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Post by Decibel on Mar 20, 2019 9:21:12 GMT -5
Sorry but I don't understand: the date of the schematics that you mentioned as "after" is year 2000 (without manual modify).
The date of the schematic that you mentioned as "older" (with manual modify) is year 2002.
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Post by Casethecorvetteman on Mar 20, 2019 9:52:26 GMT -5
It'spossible these compnents needed to be even closer of each other. So as as they are well listed in the partlist, that's well intended, and should be redone that way. Robin The second scheme is different also in many many other components. Many should be changed. I hope to restored that section despite the great difficulty in welding very small tracks. Then I inserted the drawer but after a few minutes the resistor R208 of the convergence board has smoke due to excessive heat. They was detached from pcb. I measured it and it's good but obviously there's something wrong. Those few seconds when I saw the screen there were still the wavy lines.  SR2 is a sacrificial resistor if im not mistaken, is it blowing this resistor on every convergence board you throw in there? |
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Post by robin36mac on Mar 20, 2019 9:53:48 GMT -5
Hum, indeed. I mixed myself a little, as schematics given with PCB files are not all updated... It made me invert old and new schematics. (I'll update). Some further precisions : PCB rev1 : Index 0 : R410 and C410 are absent Then they are added at index 1, manually, not on the PCB.  PCB rev3 : During index 9, they are now implemented on the PCB In partlist they then mentionned both SMD and manual so unsure of what they finally did...  PCB rev4 : Index 17, they removed it from the PCB to get back to the manual implementation (they are still present)  |
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Post by robin36mac on Mar 20, 2019 10:02:43 GMT -5
SR2 is a sacrificial resistor if im not mistaken Yes, "SR" is for Security Resistor. These are flameproof and used like a fuse. For exactly that situation. |
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Post by Casethecorvetteman on Mar 20, 2019 10:09:27 GMT -5
SR2 is a sacrificial resistor if im not mistaken Yes, "SR" is for Security Resistor. These are flameproof and used like a fuse. For exactly that situation. Seems odd that its blowing that one on every convergence board when that system board is used |
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Post by robin36mac on Mar 20, 2019 10:13:32 GMT -5
Then likely the controller board is outputing a strong convergence signal (being DC shifted or an large AC oscillation, I don't know), that just load the convergence board too much and the protection blow up...
But can't say much for my part.
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Post by Decibel on Mar 20, 2019 10:32:34 GMT -5
Yes exactly
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Post by Decibel on Mar 20, 2019 14:01:49 GMT -5
I remember having the same problem with the SR2 security resistor in my CineMax. Dummyload in august 2015 wrote that the problem was caused precisely by the bad modification of the R50 resistor in the controller board. repairalmostanything.com/post/4752/thread |
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Post by Casethecorvetteman on Mar 20, 2019 23:09:06 GMT -5
I remember having the same problem with the SR2 security resistor in my CineMax. Dummyload in august 2015 wrote that the problem was caused precisely by the bad modification of the R50 resistor in the controller board. repairalmostanything.com/post/4752/threadWhere is Dummyload these days? |
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