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Post by radiohead314 on Mar 18, 2016 7:28:38 GMT -5
Final test if I really have an image with High voltage etc. Now on to the second SMPS2 I will take out all boards again and only insert the SMPS and the SMPS2. I remember that there where leds on on the SMPS2 in standby.  Untitled by Radio Head, on Flickr |
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Post by radiohead314 on Mar 18, 2016 7:38:41 GMT -5
Oner thing on this SMPS is still strange. When I startup without J30 in standby the HTHD led is on but slowly goes out again. On another SMPS this HTHD led is never on in standby.
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Post by radiohead314 on Mar 18, 2016 8:10:59 GMT -5
When I take the subboard of this SMPS to another one th HTHD led does not come up shortly in standby. So there is a cap discharging through it somewhere that normally would not.
Hmm and only taking the subboard off, putting it on the good smps and putting it back solves this led issue.
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Post by radiohead314 on Mar 18, 2016 8:40:08 GMT -5
SMPS2 testing.
I see nothing wrong with the leds. When I do not put the Horizontal in I see 30V and hthd led are off and scanfail led is red just like a good SMPS2.
I am thinking about inserting the horizontal but perhaps than something goes wrong? Perhaps it will short the HTHD?
Also with horizontal nothing goes wrong. All leds are green.
now there is one risk left with the G2. How to test that?
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Post by radiohead314 on Mar 19, 2016 7:23:35 GMT -5
Yes! I put old tubes in this test machine so risk was lower. I measured 24 V on the smps2 to be as sure as possible and it turns out none of the smps2 is broken. Sort of a miracle or perhaps some cap was charged by the bad smps and slowly decharged over time?
Thanks for helping me out Dummyload! If you need parts we make a low price if I have them.
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Post by dummyload on Mar 19, 2016 8:15:08 GMT -5
I would not power up only smps and smps2 ,you can damage it same with horizontal ,the smps2 puts no high enough load on the fix output of smps so output is to high=danger to the smps and any extra board you insert that uses that supply ,you can test only the smps alone and even that is not without danger ,looking at the led's alone gives only an indication no information on value. (I feel now again that I did not a good job in helping you ) Your fix power supply smps is ok no need to remove all the boards.(your problem was the HTHD part of the supply) To test a smps2 board I would only remove tray horizontal and eht fuse , HTHD should be min all other voltages should be present next insert horizontal check HTHD again. Eht fuse is always last thing I enable if everything seems to be right.
About risk of g2 you mean the protection circuits or it's value ? |
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Post by dummyload on Mar 19, 2016 8:21:09 GMT -5
Wel I could not see what the HTHD problem could do wrong to the smps2 so I was curious to know what was wrong with them. |
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Post by radiohead314 on Mar 19, 2016 8:39:01 GMT -5
I looked at my notes when the smps failed. I took the smps2 to a complete other machine and there the scanfail led came up when I tested it. Also some leds whre dimly lighted in standby. Must have been a charged cap or so?
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Post by radiohead314 on Mar 19, 2016 8:59:35 GMT -5
I would not power up only smps and smps2 ,you can damage it same with horizontal ,the smps2 puts no high enough load on the fix output of smps so output is to high=danger to the smps and any extra board you insert that uses that supply ,you can test only the smps alone and even that is not without danger ,looking at the led's alone gives only an indication no information on value. (I feel now again that I did not a good job in helping you ) Your fix power supply smps is ok no need to remove all the boards.(your problem was the HTHD part of the supply) To test a smps2 board I would only remove tray horizontal and eht fuse , HTHD should be min all other voltages should be present next insert horizontal check HTHD again. Eht fuse is always last thing I enable if everything seems to be right.
About risk of g2 you mean the protection circuits or it's value ? Ok good point. The low load and high voltages might cause problems. When testing after a minute there was indeed a higher pitch squealing. I quickly shut it off. I think we could make a howto test the smps in a cine 9 (with little risk) thread. Abot g2 I know I saw retrace lines and very bright picture on the tubes as if there was no g2 when the smps failed. But I think it will not damage the phosphor. I measure the 24 V that makes the g2 to see if it was there. Than tested with old tubes in. |
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Post by dummyload on Mar 19, 2016 9:05:51 GMT -5
The set being in scanfail can explain the dimly leds in stand by , but no idee for the scan fail.
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Post by dummyload on Mar 19, 2016 9:11:49 GMT -5
There is no picture possible without g2 ,scan fail= remove g2 to protect the tubes.(among of other protection doing the same thing making g2 low )
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Post by radiohead314 on Mar 19, 2016 9:41:49 GMT -5
One more thing to test. I try to measure the ripple on C25 to see if it is dangerous to the TDA4601. First picture is the dc in 20V/div second is the dc in 500mV/div (ac coupled). I think the ripple is 1V? Is this dangerous?  Untitled by Radio Head, on Flickr  Untitled by Radio Head, on Flickr |
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Post by dummyload on Mar 19, 2016 9:57:49 GMT -5
No problem ,but I think it's a measuring error ,so your scoop is not grouded and scoop ground is at - pole c25 (hot mains ground) input scoop on + pole c25. Now put your input also on -pole c25 together with scoop ground what do you see now same settings, ac coupling 500mv/div.(carrefull you can get a chock from your scoop) |
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Post by radiohead314 on Mar 19, 2016 10:26:33 GMT -5
Right as usual  I did not even have to power up the noise is there in standby already. I guess this is 50Hz noise? How should I ground the scope proper?  Untitled by Radio Head, on Flickr |
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Post by radiohead314 on Mar 19, 2016 10:29:38 GMT -5
I need randaarde with the scope? I did not use randaarde on the barco or the scope in these measurements.
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I did not even have to power up the noise is there in standby already. I guess this is 50Hz noise? How should I ground the scope proper?
