i really enjoyed videos # 1 to # 4. i have a similar problem on my 475 which seems not easy to fix. There is noise on both tracks, apparently not generated by the power supplies. The brightness adjustment responds. The focus works but the track appears thickened and grows by acting on the input channel sensitivity increase knobs. observing a sinusoidal signal with a frequency of a few khz, a certain echo produced by the trace on itself can be seen.
Always check power supplies first, you will most likely find some voltages down or having big ripple. Just be aware that there are lethal voltages inside, so if you never worked on CRT scopes, don't even try to fix it because it might kill you,.... not joking !
Great work... I never take a chance and completely recap those old units if someone brings one in... Low ESR @ Mouser.. NEVER buy caps @ ANY asian supplier... Sorry but too many issues make it not worth the risk..
Well, it's the balance of importance of the equipment and parts cost, got many scopes, so if it fails again, i just do another video ...:-) In my experience with the 400 series, once the main caps are done, they good for another 5 to 10 years. If it would be customer equipment, i certainly would change them all.
i really enjoyed videos # 1 to # 4. i have a similar problem on my 475 which seems not easy to fix. There is noise on both tracks, apparently not generated by the power supplies. The brightness adjustment responds. The focus works but the track appears thickened and grows by acting on the input channel sensitivity increase knobs. observing a sinusoidal signal with a frequency of a few khz, a certain echo produced by the trace on itself can be seen.
Hi Luigi,..got your email, will reply at the weekend,.. sorry, very busy at the time, ... ciao Mike
Lots of work in that one scope, but interesting to see you track it down.
oops, ..missed that comment, thanks John
Just had my 475 fail today. Power up, no traces whatsoever. Controls make no difference.
Any suggestion on what to check first?
Always check power supplies first, you will most likely find some voltages down or having big ripple.
Just be aware that there are lethal voltages inside, so if you never worked on CRT scopes, don't even try to fix it because it might kill you,.... not joking !
Great work... I never take a chance and completely recap those old units if someone brings one in... Low ESR @ Mouser.. NEVER buy caps @ ANY asian supplier... Sorry but too many issues make it not worth the risk..
Well, it's the balance of importance of the equipment and parts cost, got many scopes, so if it fails again, i just do another video ...:-)
In my experience with the 400 series, once the main caps are done, they good for another 5 to 10 years.
If it would be customer equipment, i certainly would change them all.
@@dynoguy More videos??? I didn't think of that.... Doh... SMPS issues are my fave..