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Post by dummyload on Mar 15, 2016 3:04:15 GMT -5
You also can remove the fuse on the eht board so there will be no hv so saving your tubes of burn in.
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Post by radiohead314 on Mar 15, 2016 4:07:09 GMT -5
Yes thanks. I was thinking on this and since I know not what is working on this SMPS I will simple remove every board and disconnect the wires to the neckboards and remove the tray. As far as I can see I should be able to measure most voltages on the SMPS. I hope the PFC works without the controller.
Than when I am sure all are correct I shall try to disable protection on the HTHD and measure that one.
I could send the SMPS to someone for repair but I think this way I made it pretty save. If I forget something please add.
Have to place the jumper j30 to start without controller.
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Post by dummyload on Mar 15, 2016 6:11:49 GMT -5
For testing smps and smps2 it doesn't matter if pcf is on or off.
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Post by radiohead314 on Mar 15, 2016 8:05:05 GMT -5
Yes. Correct I only need the 325V from the rectifier and the TH on/off comes from the rectifier too.
If this all works we might make a HOW TO for when people want to repair there own SMPS.
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Post by radiohead314 on Mar 15, 2016 11:15:18 GMT -5
Ok I made it nice again and used different cooling pasta I checked everything twice but still not good. At the moment I am out of idea's. When I put the set in standby only with all boards removed except the PFC the green led of standby and HTHD burn on the subboard. So there is still something wrong but there is no power on the TDA. No short on the Q101 so unless the cooling pasta is shorting again I do not know what this is. The subboard is good. Tested on another SMPS. Now I have to think on what to measure. I do not risk letting it in standby to long as it will burn another fuse.  Untitled by Radio Head, on Flickr Only the standby led should be on. The other led is HTHD.  Untitled by Radio Head, on Flickr |
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Post by radiohead314 on Mar 15, 2016 14:39:19 GMT -5
Ok one thing comes to mind. There was a crack in the glimmer sheet but the man at the electronics shop said that is was no problem. But perhaps this crack is conducting? With the multimeter no conductance is measured.
I know for sure that without Q101 the HTHD led does not burn. I also know pretty sure there is 0V on the base in standby.
Also Q101 measured only condcuting with the multimeter from base to emitter and from base to collector.
I tested and it is not the sheet.
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Post by dummyload on Mar 15, 2016 15:36:28 GMT -5
It's difficult to make up whats going on from your description.So did you power mains on without j30 (stand by) and HTHD led comes on at subboard ? F100 doesn't blow anymore? smps totally rebuild? (circuit intact,no disconnections for test?) |
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Post by radiohead314 on Mar 15, 2016 16:26:28 GMT -5
Hi Dummyload. I did only put the set in standby without j30. and indeed hthd led comes up and f100 does not blow yet but that might be because i now have 3,15A fuses again. I had a 2A fuse that worked well in a good SMS. But I am a bit further. I found that removing the TDA solves it. Without the TDA and with Q101 the HTHD led does not burn. Now I have bought 3 TDA chips they all say TDA4601 but two measure different between the legs with the multimeter. One measured the same as the old and I tried that one seems that one is broken? Top two with infineon writen on them where in the smps. Left is the old one right is the one I tried. Have to try one of the others. They all say tda4601. Perhaps stupid question but is it possible that there are different versions?  Untitled by Radio Head, on Flickr |
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Post by dummyload on Mar 15, 2016 16:47:02 GMT -5
There are two circuits with a tda4601 can you check the other one if this one comes on without j30 ,try measure if +30v is precent (any voltage is fine) I think your problem is in the on/off circuit ,because without j30 The two tda4601 should not get a supply voltage at pin 9 so they can not start without j30 meaning if HTHD is on in stand by the other circuit also will be on . |
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Post by radiohead314 on Mar 15, 2016 17:11:08 GMT -5
Yes good point. I was looking at that too. Seems 30V must be there. I was wondering if perhaps that 30 V cap is still charged even when 30V is not there? It might even get charged by the hthd on the subboard?
In fact I did not dare to let the smps on for to long with the two leds. Now with one led I will measure the independent voltages tomorrow.
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Post by dummyload on Mar 15, 2016 17:21:42 GMT -5
Point is if +30v is there the other tda4601 is also working = problem is not about the tda4601 ,why are they working in stand by ? If this is valid (+30v is present in stand by) check TH1 and components around, TH1 should not conduct in stand by mode.(TH1 provides the supply for the tda's at start up ,on mode j30 present) then the +17vm takes over and TH1 is cut off again. |
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Post by radiohead314 on Mar 15, 2016 17:54:08 GMT -5
Ok what I said is that I am not sure if 30 V is there. I did a number of measurements allready and remember no green leds where burning on smps2 in the past. So I think something very odd is happening where the hthd is charging the 30 V cap so it seems 30V is there.
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Post by dummyload on Mar 16, 2016 3:17:27 GMT -5
Without j30 ,both tda's should not get a supply voltage so both supplies should be off. So if HTHD is present (the led burning) that can only happen if the tda get 's a supply voltage at pin 9,so if this tda has a supply voltage the other one should have it to and should also be working .
Solder a wire on any of the outputs of the supply that generates the +30v , and one on HTHD so you can measure if they are present without j30.
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Post by radiohead314 on Mar 16, 2016 4:24:26 GMT -5
Thanks for thinking along. It is important that we are on one line. I did the 30V check and the meter says 0V. -So there is no jumper on J30 -The TDA4601 I101 (HTHD) is not in the SMPS -0V on the 30V measured over the cap C201 -only a standby led burns I want to also point out that it is not only a standby issue. The SMPS2 broke when connected to this SMPS and there was no correct horizontal deflection and there was no G2. My feeling is that somehow the 325V on a faulty TDA4601 somehow pushed Q101 into maximum conductance. I think I am going to replace the I101 to try.  Untitled by Radio Head, on Flickr |
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Post by dummyload on Mar 16, 2016 4:42:41 GMT -5
I'm aware of the other issues , first try to solve the smps.
O.k.replace I101 test without j30 and measure +30v and HTHD again.
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