Hi Everyone, I'm starting to have some issues with my Tektronix 475 scope where after it warms up for about 5-10 minutes the beam goes out. If I press the ch1/alt/add or ch2 buttons I see the beam flash on/off. Same if I turn the trigger or delay knobs it comes in and out. Pushing the chop button brings both ch1/ch2 beams on for some reason. After a while the beam will come back. Letting the scope cool off will normally bring the beam back. Last year I did clean some contacts - this seems to be heat related though. Has anyone seen this? or is there forum out there that someone recommends specifically for old tek scopes? https://youtu.be/GZxO8YkzaBM Thanks! Matt _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
Starting point: Check the CRT DC voltages working and then not working. The shifted voltage will point you to the correct area. On 2/13/2019 1:08 PM, Matthew Rossiter wrote:
Hi Everyone,
I'm starting to have some issues with my Tektronix 475 scope where after it warms up for about 5-10 minutes the beam goes out.
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
Hi Matt, Do you have the Maintenance manual from the FTP /Techtronics section? Have a few service related manuals there... ftp://ttl.arcadetech.org/TTL/Test_Equipment/Tektronix/ I have the operators manual in my 475 that isn't scanned yet...should do it some day I guess. John :-#)# On 2019/02/13 10:08 a.m., Matthew Rossiter wrote:
Hi Everyone,
I'm starting to have some issues with my Tektronix 475 scope where after it warms up for about 5-10 minutes the beam goes out.
If I press the ch1/alt/add or ch2 buttons I see the beam flash on/off. Same if I turn the trigger or delay knobs it comes in and out.
Pushing the chop button brings both ch1/ch2 beams on for some reason. After a while the beam will come back. Letting the scope cool off will normally bring the beam back.
Last year I did clean some contacts - this seems to be heat related though. Has anyone seen this? or is there forum out there that someone recommends specifically for old tek scopes?
Thanks!
Matt
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
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I do have a hard copy of the service manual, which has a long list of "Voltage & Waveform" pages. Based on Dave Riddle's suggestion I'll go straight to the CRT Circuit page and see what I can find. It's nice they have an internal trigger source to test with. Otherwise I do happen to have a function generator handy. Matt On 2/13/2019 12:32 PM, John Robertson wrote:
Hi Matt,
Do you have the Maintenance manual from the FTP /Techtronics section? Have a few service related manuals there...
ftp://ttl.arcadetech.org/TTL/Test_Equipment/Tektronix/
I have the operators manual in my 475 that isn't scanned yet...should do it some day I guess.
John :-#)#
On 2019/02/13 10:08 a.m., Matthew Rossiter wrote:
Hi Everyone,
I'm starting to have some issues with my Tektronix 475 scope where after it warms up for about 5-10 minutes the beam goes out.
If I press the ch1/alt/add or ch2 buttons I see the beam flash on/off. Same if I turn the trigger or delay knobs it comes in and out.
Pushing the chop button brings both ch1/ch2 beams on for some reason. After a while the beam will come back. Letting the scope cool off will normally bring the beam back.
Last year I did clean some contacts - this seems to be heat related though. Has anyone seen this? or is there forum out there that someone recommends specifically for old tek scopes?
Thanks!
Matt
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
On 2019/02/13 6:54 p.m., Matthew Rossiter wrote:
I do have a hard copy of the service manual, which has a long list of "Voltage & Waveform" pages. Based on Dave Riddle's suggestion I'll go straight to the CRT Circuit page and see what I can find.
It's nice they have an internal trigger source to test with. Otherwise I do happen to have a function generator handy.
Matt
In one of the docs on TTL I saw a very nice test PCB from Tek that gave ramps, etc. Anyone have that board? ftp://ttl.arcadetech.org/TTL/Test_Equipment/Tektronix/Tektronix-Scope-Tester.pdf Would be nice to make up, or is something like that readily available? John :-#)#
On 2/13/2019 12:32 PM, John Robertson wrote:
Hi Matt,
Do you have the Maintenance manual from the FTP /Techtronics section? Have a few service related manuals there...
ftp://ttl.arcadetech.org/TTL/Test_Equipment/Tektronix/
I have the operators manual in my 475 that isn't scanned yet...should do it some day I guess.
John :-#)#
On 2019/02/13 10:08 a.m., Matthew Rossiter wrote:
Hi Everyone,
I'm starting to have some issues with my Tektronix 475 scope where after it warms up for about 5-10 minutes the beam goes out.
If I press the ch1/alt/add or ch2 buttons I see the beam flash on/off. Same if I turn the trigger or delay knobs it comes in and out.
Pushing the chop button brings both ch1/ch2 beams on for some reason. After a while the beam will come back. Letting the scope cool off will normally bring the beam back.
Last year I did clean some contacts - this seems to be heat related though. Has anyone seen this? or is there forum out there that someone recommends specifically for old tek scopes?
Thanks!
Matt
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
_______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
-- How to subscribe or unsubscribe from TTL http://seven.pairlist.net/mailman/listinfo/techtoolslist _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/
participants (3)
-
Dave Riddle (Technical Dept.) -
John Robertson -
Matthew Rossiter