Re: TEK 475: Dead on Start Up.


Steven Bender
 

1) I understand that I should start with checking the +50V (UNREG) and then 50V (REG)\, next the+ 110V, +15V, and then +5V, -8V and finally -15V.

Is this correct?.

4) I understand that TEK used a way too low margin in Voltage rating for the Tantum capacitors on power rails.
- Are there any which particularly have a bad reputation and should ALWAYS be replaced?.

or

5) Should I eventually replace ALL those tantalum caps on the various power rails with 105 deg. C electrolytic capacitors?
- or are there "solid aluminum" alternatives to the tantalums used in that era (mid 1970's - mid 1980 's ?



I’m not an expert on the 475, but I believe you are correct, starting in the 50 Volt lines.

Tant caps from the 1970’s & 1980’s had failures over time, due to impurities that crept in during manufacturing.

I tend to replace old 20V tants with 35V tants.

If Changing to electrolytic, triple the value… 22 uF/20Volt tant -> 100uF/25, 35, or 50Volt electrolytic



Steven

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