Help Tektronix 466 repair advice

[epicfatigue]

Hey everyone, i am getting into electronics and have been toying with them for the last 8 months.
I have repaired 3 CRT arcade monitors thus far so by basic recapping and fault finding,

However i am alittle stumped as to where to start with this.

I brought it to learn how they work and gain some experience however i think it is broken i have taken a video of its symptoms if someone can point me in the right direction that would be fantastic, i pulled it apart to have a quick look and this thing has caps that are massive!

https://www.youtube.com/watch?v=VDjKbOhsFks

The Manual is here.
http://www.ko4bb.com/manuals/index.p...5_Oscilloscope

[budm]

Re: Help Tektronix 466 repair advice

Does the Focus pot have any affect?

[epicfatigue]

Re: Help Tektronix 466 repair advice

i dont believe so however i will double check just putting the kids to bed.

From memory it works for a few split seconds while the green is fadding away as in the demo video (youtube link)

also the correct manual link is here

[Radio Fox]

Re: Help Tektronix 466 repair advice

Start from scratch by following the setup for "Normal sweep display" as per page 2-10 of the manual you linked to, although with the following changes:-

Set CH1 volts/div outer knob fully anticlockwise (to 5v/div).

Set "inten" fully clockwise.

Do not connect anything to any of the BNC connectors, we only want to find a straight line at this point.

The reason you are seeing green splodges on your screen is because it is a storage scope. It doesn't actually prove that the tube is working as it should.

[epicfatigue]

Re: Help Tektronix 466 repair advice

Thanks all for your response.

I get nothing when following those steps.

However now when i turn it off and on i see a flash of light for a second that appears it could be the trace line.

If i turn it off and on really fast and turn the focus it has an effect so i believe the focus might be working,

[epicfatigue]

Re: Help Tektronix 466 repair advice

Hey everyone,

First off I LOVE TEST POINTS that made it so easy!


So here are my results for test points

Expected Result
+65v +65.12v
+15v +15.05v
+5v +5v
-8V +0.71v
-15v -15.18v
+140v +139.80v


So it appears the -8V is where we start hunting!

[Radio Fox]

Re: Help Tektronix 466 repair advice

Hey everyone,

First off I LOVE TEST POINTS that made it so easy!


So here are my results for test points

Expected Result
+65v +65.12v
+15v +15.05v
+5v +5v
-8V +0.71v
-15v -15.18v
+140v +139.80v


So it appears the -8V is where we start hunting!

Yep. A missing voltage in the PSU is usually one of the easiest faults to find. Let's hope that that's the only problem.

[epicfatigue]

Re: Help Tektronix 466 repair advice

Yep. A missing voltage in the PSU is usually one of the easiest faults to find. Let's hope that that's the only problem.

I hope so!

any idea where to start looking.

iv joined the Yahoo groups and posted my findings there

[Radio Fox]

Re: Help Tektronix 466 repair advice

I hope so!

any idea where to start looking.

iv joined the Yahoo groups and posted my findings there

The Tek Yahoo group is a good place to start. I am a member there, but haven't visited it for a year or 2 now.

If I have time I'll post again later, after having a look at the schematics.

[epicfatigue]

Re: Help Tektronix 466 repair advice

okay so i finally found the correct diagram,

Layout is Page 275

And Power Supply & distraction page 292

I have highlighted all the components and i am going to remove them 1 by 1 and test them there is only a total of 17 components

3 transistors
5 capacitors
7 resistors
1 VR resistor
1 op amp


Was thinking about testing them in that order.

[epicfatigue]

Re: Help Tektronix 466 repair advice

She lives bad op amp and transistor!

[Radio Fox]

Re: Help Tektronix 466 repair advice

That's great. Hope you enjoy using it.

[epicfatigue]

Re: Help Tektronix 466 repair advice

well that was short lived was playing with it testing it, pressed the store button, now i have lost the trace again....

checked the psu everything checks out...
All the voltages are there guess something died further
Any subjections ?

[Kiriakos GR]

Re: Help Tektronix 466 repair advice

Hey everyone, i am getting into electronics and have been toying with them for the last 8 months...........I brought it to learn how they work and gain some experience............Any suggestions ?

This device needs some one been toying with scopes repairs for 15 years,
find one and pay him to do it.

Alternative advice: sale it again as damaged, and get a cheap 300$ Rigol, so to learn to use fresh made tools capable to make measurements on modern electronics.

Those instruments is all about correct measurements and accuracy, and this aged scope will need even calibration, which translates to more money and time spent and it does not worth it.

Yes I am aware that I am giving you bad news, but you may ignore them so to feel better.

[epicfatigue]

Re: Help Tektronix 466 repair advice

that was devastating to hear, sadly no one out here repairs them, and i do not have the money to buy another i will have to put in the hard yards.

I have noticed it almost seems like the beem is being deflected.

https://www.youtube.com/watch?v=tXx0g8OF3QI

[tom66]

Re: Help Tektronix 466 repair advice

Please ignore Kiriakos. I doubt the majority of tinkerers/hobbyists require high accuracy -- and besides, replacing an op-amp and transistor in the power supply is unlikely to affect the calibration one bit, no more than line voltage variations.

--

OP: Have you tried setting it to the default settings above?
PSU voltages still good (maybe replacement op-amp was insufficient?)
Is there a beam find, does this work?

[epicfatigue]

hey Tom thanks for your reply,
Yes i have tryed the default settings and not luck.

As per the video when i press the beam finder i get nothing.

But if i pull out the intensity knob (reduced scan) i get a beam.

[Kiriakos GR]

Re: Help Tektronix 466 repair advice

Please ignore Kiriakos.

Tom can you please show to us your Face ?
Any advice haves the value of the Man behind it.

Question : Are you a TRUE man or a 50/50 one ?

[epicfatigue]

Re: Help Tektronix 466 repair advice

Tom can you please show to us your Face ?
Any advice haves the value of the Man behind it.

Question : Are you a TRUE man or a 50/50 one ?

Kirakos please keep the thread crapping to a pm mate.

Wanna get this thing fixed not turn it into a war between people.

Hurling abuse at someone you cant wrap your hands around is a waste of time. I understand this will throw it out of calibration but once its working my work has one i can use to re adjust it, however no one there knows how to use it.

Anything you can contribute is a big help and i do take everything on board, and it is all appreciated. If i didn't have a family to support i would love to do this as a trade however as we all know life is not always as we would like it to be and i have missed the boat.

[Kiriakos GR]

Re: Help Tektronix 466 repair advice

There is some poor actors in this forum, that had turn in to personal hobby to insult other people.
They will get my boot on their face as reaction of defense its and every time that they act that way.

@epicfatigue
Do not worry about your thread is still here and it will be.
Regarding the scope, similar to it they are listed on Ebay for 50 to 80$,
my last suggestion about it to you, would be to do a telephone call to the nearest TEK service department in your area( state) , and speak directly with their repair man (engineer).
If you mention the problem he will have for you an quick tip that it will determine if this scope is possible to be saved.

Take care and regards.