HELP! Someone know the mainframe oscilloscope Tektronix 7000 series? I
have some 7704 with power supply broken,with same defect: don't start
the oscillator.
Some suggestion??

If you get some money send it in for repair and calibration. Cost on good
test equipment is out of site.

"giannibo" wrote in message
...
HELP! Someone know the mainframe oscilloscope Tektronix 7000 series? I
have some 7704 with power supply broken,with same defect: don't start
the oscillator.
Some suggestion??

"David Wright" wrote in message
...
If you get some money send it in for repair and calibration. Cost on good
test equipment is out of site.

"giannibo" wrote in message
...
HELP! Someone know the mainframe oscilloscope Tektronix 7000 series? I
have some 7704 with power supply broken,with same defect: don't start
the oscillator.
Some suggestion??



You can download the manual for the 7704 from
http://bama.edebris.com/manuals/tek/7704/. It should help you figure out the
problem.
The usual suspects are aging electrolytic capacitors.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

"In theory, there isn't any difference between theory and practice. In
practice, there is." - Yogi Berra

"DaveM" wrote in
:

"David Wright" wrote in message
...
If you get some money send it in for repair and calibration. Cost on
good test equipment is out of site.

"giannibo" wrote in message

...
HELP! Someone know the mainframe oscilloscope Tektronix 7000 series?
I have some 7704 with power supply broken,with same defect: don't
start the oscillator.
Some suggestion??



You can download the manual for the 7704 from
http://bama.edebris.com/manuals/tek/7704/. It should help you figure
out the problem.
The usual suspects are aging electrolytic capacitors.

both in the power supply and the mainframe itself.



just make sure you have a 7704 and not a 7704A. There's a big difference.

although both have complex series-resonant switching power supplies.

usually,you hear a clicking or "chirping" from the PS;it's trying to
start,but something is loading a supply,or a diode is shorted.
Some failures blow a lot of parts....and then the line fuse afterwards.

--
Jim Yanik
jyanik
at
kua.net

On 29 Dic, 04:43, Jim Yanik wrote:
"DaveM" wrote :





"David Wright" wrote in message
...
If you get some money send it in for repair and calibration. *Cost on
good test equipment is out of site.

"giannibo" wrote in message

...
HELP! Someone know the mainframe oscilloscope Tektronix 7000 series?
I have some 7704 with power supply broken,with same defect: don't
start the oscillator.
Some suggestion??

You can download the manual for the 7704 from
http://bama.edebris.com/manuals/tek/7704/. *It should help you figure
out the problem.
The usual suspects are aging electrolytic capacitors.

both in the power supply and the mainframe itself.



just make sure you have a 7704 and not a 7704A. There's a big difference.

although both have complex series-resonant switching power supplies.

usually,you hear a clicking or "chirping" from the PS;it's trying to
start,but something is loading a supply,or a diode is shorted.
Some failures blow a lot of parts....and then the line fuse afterwards.

--
Jim Yanik
jyanik
at
kua.net- Nascondi testo tra virgolette -

- Mostra testo tra virgolette -

Thanks for answer.The model is 7704A. I replace the fast diode.The
defect remaining is that try to start the oscillator,but isn't
stable.After several test, I found that disconnecting the transistor
TO5 on parallel to base-emitter of power transistor, the oscillator
start, but isn't stabilized.May be is the small SCR. I checked all
components, only the SCR remain... Further the semiconductor indicated
on circuit as a element with 2 emitter, what is?This machine remain on
stock for several years, so some components are gone.Is a pity ,
because this instrument is made on beautifull mode, and I try to save.
Thanking for help!!
Gianni

giannibo wrote in
:

On 29 Dic, 04:43, Jim Yanik wrote:
"DaveM" wrote
innews:gcOdnekazMCkC-janZ2dnUVZ_
:





"David Wright" wrote in message
...
If you get some money send it in for repair and calibration. *Cost
on

good test equipment is out of site.

"giannibo" wrote in message

om
...
HELP! Someone know the mainframe oscilloscope Tektronix 7000
series? I have some 7704 with power supply broken,with same
defect: don't start the oscillator.
Some suggestion??

You can download the manual for the 7704 from
http://bama.edebris.com/manuals/tek/7704/. *It should help you
figure
out the problem.
The usual suspects are aging electrolytic capacitors.

both in the power supply and the mainframe itself.



just make sure you have a 7704 and not a 7704A. There's a big
difference.

although both have complex series-resonant switching power supplies.

usually,you hear a clicking or "chirping" from the PS;it's trying to
start,but something is loading a supply,or a diode is shorted.
Some failures blow a lot of parts....and then the line fuse
afterwards.

--
Jim Yanik
jyanik
at
kua.net- Nascondi testo tra virgolette -

- Mostra testo tra virgolette -

Thanks for answer.The model is 7704A. I replace the fast diode.The
defect remaining is that try to start the oscillator,but isn't
stable.After several test, I found that disconnecting the transistor
TO5 on parallel to base-emitter of power transistor, the oscillator
start, but isn't stabilized.May be is the small SCR. I checked all
components, only the SCR remain... Further the semiconductor indicated
on circuit as a element with 2 emitter, what is?

A Diac;it triggers at ~33V IIRC.

This machine remain on
stock for several years, so some components are gone.Is a pity ,
because this instrument is made on beautifull mode, and I try to save.
Thanking for help!!
Gianni




--
Jim Yanik
jyanik
at
kua.net

On 29 Dic, 01:35, "DaveM" wrote:
"David Wright" wrote in message

...

If you get some money send it in for repair and calibration. *Cost on good
test equipment is out of site.

"giannibo" wrote in message
...
HELP! Someone know the mainframe oscilloscope Tektronix 7000 series? I
have some 7704 with power supply broken,with same defect: don't start
the oscillator.
Some suggestion??

You can download the manual for the 7704 fromhttp://bama.edebris.com/manuals/tek/7704/. *It should help you figure out the
problem.
The usual suspects are aging electrolytic capacitors.

--
Dave M
MasonDG44 at comcast dot net *(Just substitute the appropriate characters in the
address)

"In theory, there isn't any difference between theory and practice. *In
practice, there is." *- Yogi Berra

Thanks for suggestions. The items I found aren't good, are the diodes
on low voltage circuit.
I checked also the capacitor on main frame, but are ok. The defect is
that oscillator is on and off continously. Now I take out the TO5 on
parallel of base-emitter of power transitor, and remain on firmly, but
isn't stabilized.
I follow to work on, I want resume this beautifull instrument!!
Thanks a lot!!
Gianni

On 29 Dic, 00:15, "David Wright" wrote:
If you get some money send it in for repair and calibration. *Cost on good
test equipment is out of site.

"giannibo" wrote in message

...



HELP! Someone know the mainframe oscilloscope Tektronix 7000 series? I
have some 7704 with power supply broken,with same defect: don't start
the oscillator.
Some suggestion??- Nascondi testo tra virgolette -

- Mostra testo tra virgolette -

Thanks, but transport cost, custom, etc.., are out of budget. Further
I like repair my self....
HI! Gianni