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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Sat Dec 20, 2014 10:53 pm Post subject: |
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q405 and q417 is on the audio board, so i remove the hdmi board to get to it, correct?
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Sat Dec 20, 2014 11:13 pm Post subject: |
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i've got to out so it will be tomorrow morning before i can get to it.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sat Dec 20, 2014 11:44 pm Post subject: |
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Ok. No problem. These are all on the amp board. The one with the heat sink. Q405 is a surface mount on the back side and Q417 is a regular style on the front. The rest are all on the bottom.
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Sun Dec 21, 2014 8:46 pm Post subject: |
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okay mac, q421 is shorted between c and b and q422 is shorted between e and c
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Sun Dec 21, 2014 8:46 pm Post subject: |
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none of the other transistors are shorted
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Dec 21, 2014 10:37 pm Post subject: |
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| jgrice53 wrote: | | okay mac, q421 is shorted between c and b and q422 is shorted between e and c |
Remove them and test them out of circuit. Also remove Q416
You will also have to test the following.
Q424, D409, D410, ZD405, ZD406, D408, Q415, Q418.
Then switch DMM to resistance and test the following:
R458, should be 100 ohm
R483, should be 100 ohm
R487, should be 47 ohm
Then lift 1 leg of R468 and R475 and test them along with R467 and R474 and they should all read app. .47 ohms.
Last edited by macgyver655 on Sun Dec 21, 2014 11:24 pm; edited 1 time in total
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Sun Dec 21, 2014 10:55 pm Post subject: |
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Ok i will get on it tomorrow morning
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Mon Dec 22, 2014 3:51 pm Post subject: |
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okay mac, correction Q422 is supposed to be Q416. R483 is 114 ohm, R438 is open and R487 is 47 ohm. Q424, D409, D410, ZD405, ZD406, D408, check good. Q418 is a little suspect so I will check it again. I have not located Q415 yet. I will next remove Q416, Q421, and 1 side of R468, R475, R467, R474 for testing out of the circuit.
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Mon Dec 22, 2014 8:04 pm Post subject: |
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tested out of circuit and Q422 and Q421 are shorted.
tested with 1 leg removed and R468, R475, R467, and R474 are open
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Tue Dec 23, 2014 11:45 pm Post subject: |
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OK, sorry for the delay. Christmas stuff you know, lol.
So what have you found with Q415 and Q418?
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Wed Dec 24, 2014 7:15 am Post subject: |
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q418 is good, still haven't located q415
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Wed Dec 24, 2014 7:20 am Post subject: |
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i see it on the schematic but i just can not figure out which one it is on the board
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Wed Dec 24, 2014 3:40 pm Post subject: |
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Sat Dec 27, 2014 8:29 pm Post subject: |
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Hi mac, i hope you had a great christmas. I managed to get back to testing today and Q415 and Q418 test good. I also want to make a correction in the earlier post where I was giving the results of tests on the resistors and transistors...i made a typo when I listed R438 it was supposed to be R458. So at this point these are the defective parts.
R458
R467
R468
R474
R475
Q416
Q422
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sun Dec 28, 2014 4:17 am Post subject: |
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What about Q421? You previously indicated it was shorted.
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Sun Dec 28, 2014 5:49 am Post subject: |
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no Q421 is not shorted. it is the small transistor located between Q422 and Q416.
where I am doing the testing is in another room from my PC and I will get my numbers crossed sometimes from the test to the time i get to the PC to put them in. LOL, at 61 years old my short term memory is not as reliable as it once was. i will try to remember to write them down everytime in the future and stop relying on my memory.
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Tue Dec 30, 2014 4:18 am Post subject: |
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okay mac. I have the 2 transistors ordered, I have the resistors on hand.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Tue Dec 30, 2014 4:38 am Post subject: |
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Ok, good. Make sure you also change R483. It runs with R458 and is strained when Q416 and Q422 fail. It may test fine but should be changed anyways.
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Tue Dec 30, 2014 9:30 am Post subject: |
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okay, got it. i will let you know when they come in.
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jgrice53
Joined: 10 Dec 2014
Posts: 165
Location: marion, sc 29571
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| Posted: Thu Jan 08, 2015 10:02 pm Post subject: |
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SUCCESS mac...it works. Seems like all the bad components were on the amp board. It powers on and goes through the setup process with no errors. I have not yet connected speakers. I replace the 2 transistors and 4 resistors. Even though the resistors I have are labeled .47 ohm, they actually test at .7 and .8 ohms. I double and triple checked them, as well as .51 ohm resistors testing at .8 and 1.0 ohm. The resistors were new in the pack that have never been opened so I am chalking it up to a discrepancy in my meter. I really really want to thank you for all your fantastic help.
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