Tek TDS500/600 series scopes capacitor replacement best practice

[rodd]

Dear all,
I have a TDS680A in which I want to to a full recap job.
I have been reading threads with different suggestions, like:
 1- replace all by 33uF/35V electrolytic smd capacitors
 2 - replace all  by 33uF/??V tantalum smd ( what should be the correct Voltage spec for tants?)
 3- replace all by same value as original using radial electrolytic capacitors with lead bent to fit the solder pads.

Can you post your experience/views on this subject?
Indication of the preferred cap replacement manufacturer/product number would be greatly appreciated.
Best regards,
Roger

[wn1fju]

On my TDS520, I used electrolytics to replace all the SMT caps (a mix of 33uF and 10uF).  If I remember, I used Panasonic low ESR, 105 degree radial capacitors for most of them.  There were some caps under a shield, so I had to use smaller height ones for those and I could only find 85 degree caps for them.  The replacement method was 1) twist off the SMT cap with pliers, 2) unsolder the leftover leads still attached to the board, 3) scrub the area with alcohol, 4) look through a magnifying glass for any broken/corroded traces/pads around the cap, 5) cut and bend the electrolytic leads into a short "L" shape, 5) solder them onto the pads, 6) scrub off any flux with alcohol.  It goes fairly quick once you get going.

My TDS520 had plenty of SMT caps that were oozing as well as plenty that were not oozing but had lost almost all capacitance.  You really can't tell just by looking, so it is best to replace all the SMT caps on all the boards as you are planning to do.  And, of course, look in the power supply for any of those gold-colored Rifa suppression caps - those should be replaced without question.

As you have indicated, there are lots and lots of threads on repairing these TDS scopes.  Good luck.