#16
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So what would you suggest next?
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 |
#17
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If I put the probe anywhere around the flyback, I get the same as in the focus picture in the previous post. Lots of ringing. Of course I don't know if that's just because I'm not making electrical contact and just picking up on the radiating signal.
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 |
#18
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I scoped the leg of the diode that connects to the 500ohm resistor that feeds the wiper of the ABL pot, blah, blah, blah. This is what I got. It's an ugly waveform, that's for sure, but what does it mean? It was with a volts/div of .2 and a time/div of 20us.
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 Last edited by TinCanAlley; 09-27-2013 at 09:17 PM. |
#19
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It is really difficult to follow what is going on with the schematic incomplete and in a different thread.
Can you post a bigger chunk, so we see where the ABL signal from the pot wiper goes? Somewhere into the video amps, I assume. Scope the B+ voltage that feeds the video amps, and look for ripple/ringing there. Check the zener diode using the diode check on a DMM as a first go. That will conclusively check for opens/shorts. I'm betting it is still good though. Im thinking you might have a bad bypass cap in the video amp somewhere. |
#20
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I'll do the B+ tomorrow. The DMM will tell me if the diode is working as far as passing in one direction. Wouldn't I need to supply 7.5V to open for testing in the other direction? Would a 9V battery do the trick?
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 Last edited by TinCanAlley; 09-28-2013 at 12:39 AM. |
Audiokarma |
#21
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Okay, here's the B+. The DMM has it at 129.8V and the waveform is attached. It doesn't look clean at all. Not sure why there are two on the scope. Scope had the 10x probe, volts/div of 1 and the time/div of 10us.
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 |
#22
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Okay, I just scoped the B+ at the test point which gets it directly from the source and something odd is happening to the waveform. Hopefully someone here has the answer.
Take a look at the two attached pics. The first one is the rippled wave form with a thin trace line. Then take a look at pic two. The line is starting thin and spreading out, then back, then out, etc. It takes about 4 to 5 seconds for the process and it keeps repeating. So what would cause this?
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 |
#23
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OK TCA the "ground" on the tripler is grounded in SOME sets. On those the ABL will usually be taken at R356, the "low" end of the FBT HV winding. Think of yours as the low side of the tripler. R362 & R359 will have the HV current through them, the brighter the pix the more current so more voltage across the resistors. The Zener diode will keep the voltage at its cathode at 7.5 V or less. Under 7.5V the zener does nothing. Result is the ABL control will adj. between apx 0 V & 7.5 V If a dark pix it will adj. between 0 & < 7.5 V & send that to the ABL transistor. Hope that helps 73 Zeno |
#24
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 |
#25
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The video out B+ is 240 VDC & filtered by C270. This cap is notorious for causing jailbars in almost any brand. Check C270 before going further. In any case there is 5V of garbage there that shouldnt be......... 73 Zeno |
Audiokarma |
#26
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So I should be locating the 240V B+? I'll see if I can locate it on the schematics. Oh, and C270 was changed during the initial recap when I got the set.
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 |
#27
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 |
#28
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Edit: I see you did tell the settings on a previous waveform. I suggest you check the filter cap as suggested by Zeno. Last edited by old_tv_nut; 09-28-2013 at 08:24 PM. |
#29
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What is the amplitude of that ringing on the 240V line? What is the DC voltage?
Can you try temporarily bridging another cap between 240V line and ground to see if it improves the bars or cuts the amplitude of that ringing? Post the section of the schematic that shows C270 and this supply for those of without a Sams handy... |
#30
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I'll double check the cap. I is new and tested good w/in spec when I tested it before install.
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Pioneer SX-1080, Pioneer PL-115D, Pioneer CT-F9191, Pioneer RG-1, Wollensak 8050A, Akai 4000DS MkII, Pioneer CS-05 & Polk 1.2TL Denon 5803A, Pioneer DVL-700, Pioneer CT-W603RS, Toshiba HD-A3, D-Link DSM-520, Dish VIP-722, Polk 1.2TL, CSi5, LS/fx, RT-800 and PSW-650 Last edited by TinCanAlley; 09-28-2013 at 09:26 PM. |
Audiokarma |
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