nashou
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Post by nashou on Mar 3, 2014 21:58:13 GMT -5
I'm showing R493 is 33ohm. Attachments:
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Post by mastertech on Mar 3, 2014 21:59:22 GMT -5
You are on the wrong page. That page is for the 1022 and 42. The 822 is on page 84 and 85.
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nashou
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Post by nashou on Mar 3, 2014 22:03:21 GMT -5
You are on the wrong page. That page is for the 1022 and 42. The 822 is on page 84 and 85. Crap!!!! Nashou |
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nashou
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Post by nashou on Mar 3, 2014 22:08:14 GMT -5
Ok I do think I have 33 ohm 1 watt resistor. its the same resistor for the marquee VNB Video path to the cathode.
Think that is the issue? R551 reads ok.
Nashou
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Post by mastertech on Mar 3, 2014 22:09:11 GMT -5
Ok, lets just start from here. Confirm and replace if needed.
R493 = 33ohm, 1w
R551 = 100ohm, 1w
C419 = Test for short with DMM, ESR (I think you have one, right)
C531 = " " " "
You didn't respond to my question on R439 and R415. (FL was the problem channel, right?)
I'll be back tomorrow.
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Post by mastertech on Mar 3, 2014 22:12:27 GMT -5
Oh, also while you have Q417 removed, go back and test for DC again on CP402. Just a quick assemble. Don't worry about all boards and screws being installed.
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nashou
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Post by nashou on Mar 3, 2014 22:14:21 GMT -5
Ok, lets just start from here. Confirm and replace if needed. R493 = 33ohm, 1w R551 = 100ohm, 1w C419 = Test for short with DMM, ESR (I think you have one, right) C531 = " " " " You didn't respond to my question on R439 and R415. (FL was the problem channel, right?) I'll be back tomorrow. Only R439 yes that is a 1/4 watt. R551 is ok. to test cap i have to remove them for ESR. Nashou |
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nashou
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Post by nashou on Mar 3, 2014 22:35:11 GMT -5
Ok, lets just start from here. Confirm and replace if needed. R493 = 33ohm, 1w R551 = 100ohm, 1w C419 = Test for short with DMM, ESR (I think you have one, right) C531 = " " " " You didn't respond to my question on R439 and R415. (FL was the problem channel, right?) I'll be back tomorrow. Only R439 yes that is a 1/4 watt. R551 is ok. to test cap i have to remove them for ESR. Nashou Ok No Short on Caps from just using a continuity test and they both measured ok regarding their uf Values. But i put the board back in with no heat sink and used some paper for an insulator so it wouldn't touch the chassis. I used the Test points instead for DC and it was still there.  |
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nashou
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Post by nashou on Mar 4, 2014 12:14:00 GMT -5
Ok removed caps and checked with my Tester all good low ESR .26 ohms.
I put a CC 33.3 ohm resistor i had as a pulled part from my Marquee's VNB. So that is in.
So should I put a new KSA transistor in and try again?
Nashou
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Post by mastertech on Mar 4, 2014 12:47:24 GMT -5
I would recheck Q407, Q408, Q412 and Q409, and ZD402,D403,ZD403 and D404. Also, that R439 being only 1/4w has me concerned. That is on the mosfet drive line and that 1/4w is limiting current. Amp circuits require perfect balance to work properly and this could be causing an unbalance.
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nashou
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Post by nashou on Mar 4, 2014 13:03:04 GMT -5
They all read fine. No shorts.
I'll try to find a 100 ohm 1 watt none on hand. I do have extra 47ohm 1 watt's that i ordered for the one that was bad, I could put them in series that comes to 94 ohms pretty close for now till I get
a proper part right?
Nashou
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Post by mastertech on Mar 4, 2014 13:19:57 GMT -5
Just yank the right one out of one of those 1021's you bought.
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nashou
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Post by nashou on Mar 4, 2014 14:58:23 GMT -5
Just yank the right one out of one of those 1021's you bought. I didn't even think of that!! I'll order some anyways and pull one out later tonight when I get home from work. |
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nashou
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Post by nashou on Mar 5, 2014 19:13:52 GMT -5
Ok So I put The parts in and still the same.So I saw there are some SMD Transistors on the back side of the board. And some have shorts between the legs on the same side of the SMD not sure if this is normal or not.
These are Q 403, 415, 427, 439 and 451 all have the HIGH B+ line to them and all the test points like TP401 have the +53 VDC on pin 1 and 3 .
So if these went bad would that cause the measurements I am having?
I need to remove one and test out of circuit to be sure of course as I can not see anything that would give me a .000 on my diode test for the two pins but read ok if i test the single pin to either of the pins on the same side.
I think they are all 2N5401S parts
SO I looked up the data sheet and the short is between the Emitter and base.
Nashou
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Post by mastertech on Mar 5, 2014 19:39:54 GMT -5
Those are protection transistor for thermal protection. There is a resistor across emitter and base so you may be reading that. I do not see where they would put B+ on the outputs. Also unlikely they would all blow out. Since the same DC is on all lines it has to be something common with every channel.
Can you DC test all pins on CP404 to see if it is more then 1 protect line being turned on?
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