• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Need recapping tube radio advice

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rayma

Member
2011-04-29 8:37 pm
I did run into a problem replacing electrolytics on tubes one time-I think type I used were not high enough current.
I will try srague 715p. So if circuit put out 50v you should use 100v lytic?

The Vishay/Sprague 715P are film caps, and so are good for smaller capacitance values, around 1uF or less.
If you need electrolytics, use high ripple current, 105C rated caps for this, at around 3/4 of their rated voltage.
For example, if the circuit has 50VDC, use 75V-80V rated electrolytic caps.
 
Don't be tempted to 'recap' the RF parts unless you know what you are doing, and can reliably distinguish between a decoupling cap (which can be replaced, if necessary) and a tuning cap (only replace if faulty and you know how to re-align). Elsewhere, replace only one or two components at a time then retest to make sure it still works. Check resistors too, and replace any which are more than about 50% off value.
 

gto127

Member
2007-05-09 2:51 am
Thanks DF96. The more I look at this I'm considering to send to a specialist. Many of caps/resistors are faded beyond recognition. service manual has 20 caps in here but only 14 are obvious caps. Anyone know a good tube radio repair center in U.S.?
 
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