Tektronix 453 scope repair questions

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grant fair
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Tektronix 453 scope repair questions

Post by grant fair » Tue Mar 16, 2004 10:43 pm

About a year after I bought a surplus Tektronix 453 the CRT stopped displaying anything. I assume this may be the high voltage winding on the transformer which has gone (apparently this is common with this scope?), or a bad CRT.<p>I bought another 453 recently for parts - it's serial number shows it is one of the early (nuvistor?) tube versions. The other is all transistor.<p>Can I swap the transformer and CRT between these?<p>Grant
Grant

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Externet
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Re: Tektronix 453 scope repair questions

Post by Externet » Wed Mar 17, 2004 7:49 am

Hello Grant.
Swapping parts by guessing will hardly take you anywhere. You are assumming bad high voltage winding apparently with no backing reason. Check ALL supply voltages first, check the high voltage transistor has signal fed into its base and is not shorted/open. You must have the service manual or it will be a painful blind job.
Hope you nail it,
Miguel
- Abolish the deciBel ! -

grant fair
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Re: Tektronix 453 scope repair questions

Post by grant fair » Fri Mar 19, 2004 9:19 pm

Thanks Miguel. I have sent for a manual, but it has not yet arrived.It will make checking those voltages easier <g>. <p>Thanks for pointing out another potential problem to check. I don't know much about scopes and my troubleshooting skills are rudimentary. So I may be back here for more advice soon.<p>Grant
Grant

RogerJB
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Re: Tektronix 453 scope repair questions

Post by RogerJB » Sun Mar 21, 2004 11:31 am

Grant
I have had a 453 for about 10 years. Has been shipped across country. Works great. I have the Instruction manual part # 070-0478-00. It covers operations, circuit description, maintenance and parts list and diagrams. I would not sell this manual as I still have my scope but would be willing to work with you to provide info.
Roger

grant fair
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Re: Tektronix 453 scope repair questions

Post by grant fair » Sun Mar 21, 2004 9:09 pm

Thanks Roger, that's great, I will take you up on your offer. The rented manual should get here this week and then maybe we can get started. I will look at the power supplies first, I guess, and see what I find, then let you know.<p>Grant
Grant

Dean Huster
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Re: Tektronix 453 scope repair questions

Post by Dean Huster » Mon Mar 22, 2004 7:13 pm

Don't forget that there's a lot of things that affect the beam. Regardless of the product, the power supplies are always the first thing to check, for everything depends upon them.<p>Check the HV at the HV test point to make sure that it is dead before you make any assumptions on that point.<p>Check the Z-axis voltage to make sure that the CRT bias is correct. No unblanking pulse means no beam.<p>Check that your sweep is working. The scope won't unblank the CRT until a valid sweep is generated.<p>Check the voltages on the vertical deflection plates and make sure that they're equal by adjusting the vertical position control. If one side of the vertical amp went south, so will the beam.<p>And just in case .... make sure that you haven't been sucked into an operator trap and that the scope isn't in the single sweep or normal (vs. automatic) sweep mode!<p>Dean<p>[ March 22, 2004: Message edited by: Dean Huster ]</p>
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.


grant fair
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Re: Tektronix 453 scope repair questions

Post by grant fair » Wed Mar 24, 2004 10:05 pm

Thanks for the rental information, I'm in Canada and have rented the manual for $25. I can zerox it. Getting stuff transported from the US can be costly and the only paper manual was selling for $46.00 US. I did check it out before deciding.<p>Grant
Grant

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