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#1
08-30-2013, 08:33 PM
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Anyone ever repair a B&K 470?
I have this unit and just had to resolder one of the main capacitors as the lead just pulled out of the board. After doing this, I was able to set the proper heater voltage, G2, G1 and test the emissions of the color guns (all tested fine). I wasn't, however, able to test the leakage of the heater or G1. The meter would drop immediately to 0 for both tests on all three guns. I'm pretty sure there is something wrong as this tube wouldn't provide the brightness and image it does if there was a major leakage in all the guns and heater.
So anyone here ever repair one of these units? I was able to get the schematics and parts list, but the only thing the service manual has is how to calibrate the heater voltage of the unit, nothing else. I'm hoping someone can point to an area for inspection/repair.
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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 
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#2
08-30-2013, 10:07 PM
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No leakage (G1) or heater-cathode leakage is indicative of a good CRT. I've seen only a few (out of many hundreds tested) that had any leakage. I own 4 B&K 470s, one is my original from the early 90s, and three were passed on to me when my dad died. All 4 had the crappy plastic case hinge fail - I use a piano hinge and some self-tapping screws to replace it. The latches on three are also broken - Velcro cloth and some rubber cement fixed that.
As long as you can set the line adjust, G1 and G2's, and your CRT shows emission, I'd say you have a good 470. They are workhorses. Cheers,
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Brian USN RET 22YRS (Avionics/Cal) CET-Consumer Repair and Avionics ('88) "Capacitor Cosmetologist since '79" When fuses go to work, they quit!
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#3
08-30-2013, 10:09 PM
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No, there's nothing wrong with it. When testing for leakage or shorts, the pointer should go to 0. If the pointer rises on any of the leakage test functions; then, a short or leakage is indicated.
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http://www.youtube.com/user/radiotvphononut
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#4
08-30-2013, 10:32 PM
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Hmmm... The manual says as long as the needle is in the yellow section, the leakage is acceptable. The 0 mark is just outside the yellow section, so I figured something wasn't right. I guess 0 is the start of the yellow section.
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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
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#5
08-31-2013, 12:53 AM
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As long as it doesn't rise out of the yellow, the tube is acceptable. Actually, I don't think I've tested a tube where the leakage test registered in the yellow. It either didn't move the pointer or it had full blown leakage/short.
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http://www.youtube.com/user/radiotvphononut
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#6
08-31-2013, 10:45 AM
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Quote:
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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
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