Hi, I just bought this tek and while it passes all the selftests,
it's really flaky at startup.
When you press the on/stby button the lights blink once , you can hear some
relays switching and it goes dead.
Then I keep pushing the button and eventually it "catches on"
from then on it operates flawlesly.
Sometimes it takes 3 tries sometimes ~30.
Has anybody seen the simmilar problem (solution would be nice)?
Thanks.

"janek77" wrote in
:

Hi, I just bought this tek and while it passes all the selftests,
it's really flaky at startup.
When you press the on/stby button the lights blink once , you can hear
some relays switching and it goes dead.
Then I keep pushing the button and eventually it "catches on"
from then on it operates flawlesly.
Sometimes it takes 3 tries sometimes ~30.
Has anybody seen the simmilar problem (solution would be nice)?
Thanks.




It's old enough for the electrolytic caps ESR to be rising.
Time to re-cap the power supply.Use 105DegF low-ESR caps.

--
Jim Yanik
jyanik
at
kua.net

"Jim Yanik" bravely wrote to "All" (17 Feb 06 02:45:02)
--- on the heady topic of " Tektronix TDS340, hard to turn on?"

JY From: Jim Yanik
JY Xref: core-easynews sci.electronics.repair:358540

JY "janek77" wrote in
JY :

Hi, I just bought this tek and while it passes all the selftests,
it's really flaky at startup.
When you press the on/stby button the lights blink once , you can hear
some relays switching and it goes dead.
Then I keep pushing the button and eventually it "catches on"
from then on it operates flawlesly.
Sometimes it takes 3 tries sometimes ~30.
Has anybody seen the simmilar problem (solution would be nice)?
Thanks.



JY It's old enough for the electrolytic caps ESR to be rising.
JY Time to re-cap the power supply.Use 105DegF low-ESR caps.

Would it be too obvious if it might be an intermittant power switch.

A*s*i*m*o*v

Would it be too obvious if it might be an intermittant power switch.

I'd certainly check into that before replacing capacitors.

I'm almost certain it's not a switch, to me it definitely looks like
ps is trying to start , but it shuts down almost immediately on overcurrent
of some sort.
For now its merely annoing, if it gets any worse I'll try the caps.
Thanks.


"Charles Schuler" wrote in message
...

Would it be too obvious if it might be an intermittant power switch.

I'd certainly check into that before replacing capacitors.

"janek77" wrote in
:

I'm almost certain it's not a switch, to me it definitely looks like
ps is trying to start , but it shuts down almost immediately on
overcurrent of some sort.
For now its merely annoing, if it gets any worse I'll try the caps.
Thanks.

It could just be a single electrolytic,perhaps the housekeeping cap that
supplies the switching control IC.I've seen PS's do just like you described
and it was that one cap with a high ESR.




"Charles Schuler" wrote in message
...

Would it be too obvious if it might be an intermittant power switch.

I'd certainly check into that before replacing capacitors.






--
Jim Yanik
jyanik
at
kua.net

For now it seems to be getting better, as I had it plugged in for last
couple of days.
I,m not rulling a "noisy pushbutton" completely out (yet),
but to me it seems like that whatever cap is responsible it seems to be
"forming" again.
There two distinct possibilities:
1: "noisy" switch, which is getting better with use
or
2: a cap thats getting "formed" after long discharge.
Whats your pick?

"janek77" wrote in message
. ..
Hi, I just bought this tek and while it passes all the selftests,
it's really flaky at startup.
When you press the on/stby button the lights blink once , you can hear
some relays switching and it goes dead.
Then I keep pushing the button and eventually it "catches on"
from then on it operates flawlesly.
Sometimes it takes 3 tries sometimes ~30.
Has anybody seen the simmilar problem (solution would be nice)?
Thanks.

I'd suggest replacing the electrolytic caps in the power supply. I had to
do that with my Tek 2225 before it would start behaving itself.