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Old 14th January 2008, 08:58 PM   #11
Cobra2 is offline Cobra2  Norway
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http://www.tone-lizard.com/B%26K707_calibration.htm

http://bama.edebris.com/manuals/b&k/700/


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Old 15th January 2008, 12:44 AM   #12
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I have a 707, much the same as the 700.

I have been going through a tube collection acquired over the years, caddies, etc.

Many new tubes are weak or bad. Repairmen kept the old tubes for some reason. Either they sold them to suckers, tried them in another t.v., or took them back to the distributor for a replacement.

Many tubes are annual re-tube leftovers of industrial equipment maintainence. Again, they kept the old tubes, possibley for warranty verificaton in the event of a dispute.

With experience you can spot the old tubes, but I couldn't years ago. With Sylvania and RCA the color of the chalk changes. Can also match the logo on tube with vintage of box. Many new tubes have bent pins from the factory and also a new tube can have bent pins because someone tried it to test a circuit and then put it back in the box.

Current production tubes can be factory seconds. Sovtek, from what I have gathered, sells crates of unchecked tubes. The duds are probably sold to the unwary. The tolerances of commercial tubes are very sloppy. JAN (military) tubes never check this way, they are always very strong: far into green on the meter. They are screened for quality. I have many Sovteks that are very weak from major distributors. Sovtek evidently leaves the quality control to the buyers.

With power tubes a brown ring around the getter spot means lots of hours.

Calibrate your 700: three adjustments. Check the component values of the tester circuit and replace electrolytics with NEW ones, not NOS. Buy them from a major distributor that has sufficient turnover to have really new caps in stock.

Clean the socket terminals with toothpicks, but watch the wood residue. Dip the toothpick in tarn-X and rotate it in the terminals. You will see when the crud stops coming loose.

Also, worn sockets are a problem. Replacing a socket is easy if you cut the whole terminal off of the old socket and solder the whole thing onto the new socket terminal. Take pictures first.

Also, in case you don't know, the lower test is only an emissions test. Mark
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Old 14th March 2009, 04:59 PM   #13
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I recently purchased a BK700 but it doesn't work.
I disassembled it and found the cap on the test meter was not connected (its connect on one side the positive side and the other lead is off .could someone tell me where it connects.
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