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 Post subject: recap
PostPosted: Oct Sun 26, 2003 3:36 am 
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Location: trophy club tx
Are the tolerances more critical on a tube testor for the caps then a radio?<P>------------------<BR>


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 Post subject: recap
PostPosted: Oct Sun 26, 2003 4:15 am 
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Location: Grand Blanc, MI USA
The answer to this question is the same as for a radio. Caps in tube testers are used for different things. Filter caps are probably not going to be critical. Then again, some testers employ "tuned" circuits to create and filter the grid signal frequency. Capacitance would be more critical here. Some caps just block DC or are bypass caps--not so critical. Tube testers, that I have seen, do not use caps as reference standards, like some capacitor analyzers do. So--there will probably be no need for real high precision caps in a tube tester. But--since it's often hard to know just what the function of a cap is--best to use one of the same type, capacity, and voltage rating. When I say same type--I mean do replace paper caps with poly--but don't use ceramics unless you know what the applicaition is, and that the ceramic cap won't be a problem.<P>------------------<BR>


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 Post subject: recap
PostPosted: Oct Mon 27, 2003 10:25 pm 
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Hi Michael,<P>I would be more picky about values with a tube tester, as with any other piece of test equipment. In a consumer radio, for example, I would not hesitate to use a 0.22 mfd to replace a 0.27. In a piece of test equipment, I would add a .047 in parallel with the .22 if I couldn't find the correct nominal value.<P>------------------<BR>73 de Leigh W3NLB


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 Post subject: recap
PostPosted: Oct Tue 28, 2003 1:07 am 
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Leigh, that is a good point, and being picky will never get someone in trouble--being sloppy often will. I should have written my response a bit differently. Capacitors are likely to be more critical in a tube tester than a radio, I just meant to illustrate the fact that there are many uses for caps in both radios and test equipment and different applications demand different levels of precision.<P>Have been using that Pace solder station today and all I can say is WOW. It solders to a chassis so easily, yet can be turned down to do delicate work. Should have bought one of these some time back.<P>Oh, and about being picky. I am rebuilding a couple of Eico HF-60 amps for a customer. The filter caps are rated at 500 volts and I don't have any. Thought perhaps I could use 450's. I checked the cap voltage and sure enough the first cap had 505 volts on it with a line voltage of 125. So--450 volt caps would just not do. I ordered some 500 volt caps from AES.<P>------------------<BR>


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 Post subject: recap
PostPosted: Oct Tue 28, 2003 2:56 am 
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Hi Chris,<P>Glad you like the Pace. I was amazed at how well it does the heavy lifting <IMG SRC="http://antiqueradios.com/forums/smile.gif"><P>I think you'll find that most caps have lower voltage ratings than would be dictated by the circuit design. The best thing to do is disconnect the B+ load and measure the open circuit AC voltage from the transformer. Multiply that by 1.414 and you'll get the true peak voltage that the equipment can produce. This should be the absolute minimum voltage rating for the filter caps. If you use this value, you won't experience a failure even if something else happens that removes the load from the supply output (which can happen).<P>------------------<BR>73 de Leigh W3NLB


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 Post subject: recap
PostPosted: Oct Tue 28, 2003 4:45 am 
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Location: trophy club tx
Thanks guys I will keep the same values just to be on the safe side since I am new to recapping.I thought it might be more critical in a piece of test equipment.<P>------------------<BR>


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 Post subject: recap
PostPosted: Oct Wed 29, 2003 6:24 pm 
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Location: trophy club tx
What model Pace are you guys using I need to buy a good solder station.I am using an old solder gun yep it looks like a small pistol.<BR> I was looking at Weller and now you say Pace.<BR> I might get one from EBay but there are several model numbers.<P>------------------<BR>


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 Post subject: recap
PostPosted: Oct Wed 29, 2003 6:40 pm 
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It's a Pace ST45, about $150.<P>------------------<BR>


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 Post subject: recap
PostPosted: Oct Wed 29, 2003 7:46 pm 
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Location: trophy club tx
Found one on the net for 149 but you get a 50 dolar rebate.Then they also have a ST25 that is almost the same but not digital or auto shut off price after rebate 49 dollars.<BR> I might get that one I am a little scared of the digital thing.(more things to mess up)<BR> I am still in the anolog zone.<BR><P>------------------<BR>


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 Post subject: recap
PostPosted: Oct Wed 29, 2003 9:40 pm 
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Hi Michael,<P>I'm always slightly suspicious of microprocessor controlled items. I've designed over 50 such products, and I know the temptation to cut corners to save $.<P>However, I have no reservations about using the Pace equipment. They're the largest manufacturer of such things in the world (by far), and they have an excellent reputation.<P>I really like having the auto-off feature. I never worry at night whether I remembered to turn the iron off when I left the shop <IMG SRC="http://antiqueradios.com/forums/smile.gif"> And I think the auto-setback dramatically increases tip life.<P>------------------<BR>73 de Leigh W3NLB


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