Works fine, but are there any recommended routine replacements for the
no doubt aging caps in the power supplies??

TIA!

and happy holidays

Meat Plow wrote in :

On Sat, 22 Dec 2007 05:21:15 -0800, tek_freak wrote:

Works fine, but are there any recommended routine replacements for the
no doubt aging caps in the power supplies??

TIA!

and happy holidays

I don't think replacing capacitors is part of a service routine
I have an old Tek 453 scope and it's virgin inside and has been used
extensively over the past couple decades I've owned it.



that's because it doesn't have any switching power supplies in it.
They are tough on electrolytics.

Their life will depend on how much use the scope gets.

--
Jim Yanik
jyanik
at
kua.net

Jim Yanik wrote:
Meat Plow wrote in :

On Sat, 22 Dec 2007 05:21:15 -0800, tek_freak wrote:

Works fine, but are there any recommended routine replacements for the
no doubt aging caps in the power supplies??

TIA!

and happy holidays
I don't think replacing capacitors is part of a service routine
I have an old Tek 453 scope and it's virgin inside and has been used
extensively over the past couple decades I've owned it.



that's because it doesn't have any switching power supplies in it.
They are tough on electrolytics.

Their life will depend on how much use the scope gets.

That's a tough one.
Rule number one: "if it ain't broke, don't fix it."
But, there were a few years where electrolytics leaked and made
a mess of the circuit board. At least look for little dots of
electrolyte on the board near electrolytics.

Then there's another time bomb waiting in electronic gear.
Had a LCD monitor that had an open cap (actually just high ESR) in the
switching regulator.
The average voltage out was still 5V, but the peak voltage of 20V
took out the electronics board.
I think we're gonna see a LOT more of this type of failure in the coming
decade.
I'm still a fan of rule number one...
mike

--
Return address is VALID!

mike wrote in news:fVgbj.25523$gF4.19513@trnddc02:

Jim Yanik wrote:
Meat Plow wrote in
:

On Sat, 22 Dec 2007 05:21:15 -0800, tek_freak wrote:

Works fine, but are there any recommended routine replacements for
the no doubt aging caps in the power supplies??

TIA!

and happy holidays
I don't think replacing capacitors is part of a service routine
I have an old Tek 453 scope and it's virgin inside and has been used
extensively over the past couple decades I've owned it.



that's because it doesn't have any switching power supplies in it.
They are tough on electrolytics.

Their life will depend on how much use the scope gets.

That's a tough one.
Rule number one: "if it ain't broke, don't fix it."
But, there were a few years where electrolytics leaked and made
a mess of the circuit board. At least look for little dots of
electrolyte on the board near electrolytics.

Then there's another time bomb waiting in electronic gear.
Had a LCD monitor that had an open cap (actually just high ESR) in the
switching regulator.
The average voltage out was still 5V, but the peak voltage of 20V
took out the electronics board.
I think we're gonna see a LOT more of this type of failure in the
coming decade.
I'm still a fan of rule number one...
mike


TEKs 1700 series of video monitors had an orange 1000uf/10v cap on it's 5v
line,and the cap had too high an ESR,and the PS regulated off that 5v
line,so when the cap began to fail,the OTHER supplies climbed really
high,and the +40v unreg supply rose to +60 or more,and the PCB under the HV
oscillator xstr charred due to the excess dissipation,and then became
conductive and overloaded the PS,putting it into current limit("chirp" or
burst mode").We even had caps burst open.
I ended up Dremelling out the charred area,filling with epoxy,re-laying the
traces and setting eyelets.(got to be pretty good at it)
I had to do that on a lot of 1700 power supply boards,before we changed the
1000uf /10v cap to a better grade low-ESR cap.Eventually,we changed vendors
and all the electrolytics used were better grade,low ESR caps.

That was one of my most common repair tasks,re-capping power supply
boards(all switchers),throughout a number of TEK products.

--
Jim Yanik
jyanik
at
kua.net