TeK 454 Scope Repair? Plus a good manal site!

Thomas

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Well I went ahead a bought another scope. I knew it didn't work but could not refuse the purchase. So I am kinda wondering if anyone has any resources or links that I might study in order to fix this old girl?

I have power and lights but the screen is dark. Anyone ever work on one of these before and bring it back to life?

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I found a pretty cool manual site in case anyone doesn't know about.

http://bama.edebris.com/manuals/
 
Take it into a VERY dark room... Power it up, turn the intensity control all the way up and see if you have any glow on the CRT. If not, turn it off and watch the screen to see if you have green glow then.

I bought an old portable Tek scope and it was a damn nice one that came out of a military surplus auction. It didn't appear to light up, but when put into a darkened room, it sure did! I found the fuses were replaced with fuses that were WAY too small for it (The damn board was even labeled!!!) and the H/V deflection circuitry had some of the wires disconnected.

Reconnected things and placed new fuses in it... and it worked like a champ.

Turns out someone in the military wanted a new scope. ;)

Anyway, if you see green glows then you probably have high voltage and need to start tracing through the deflection outputs...
 
Thanks for that post. I will check that out. I also here a weird noise its not like hum but more like a buzz... Kinda Strange.
 
Maybe you have a HV leakage issue or something like that.

Take the cover off the scope, turn the lights off, and look for glowing. Maybe it's HV leaking.

RJ
 
Hey Rj,

Here are some snaps...

http://www.mrrepair.net/scope/

The boards inside the scope were made in 1965/1966. I am one year older than this thing.

Ok I found my first issue. The power cord is showing bare wire. I know these were touching inside. There is no way they couldn't have been.

This is not an easy scope to work on that is for sure. Everything is stuffed inside like a sardine can. I am not sure yet how to gain access to the power cord for a repair. Any ideas on this? I can supply pictures!

The 25 meg pdf of the manual has not been much help that I can tell.

http://bama.edebris.com/manuals/tek/454/
 
Wow! I'm surprised you didn't blow every breaker on the block!

HP's scopes are somewhat modular, but like any good Chinese puzzle you need to find the correct starting place. I've never seen that one, but there is usually one module that has snap down pins instead of screws. That is usually a good place to start. IIRC, it is usually in the top right corner if you are looking from the back. Don't hold me to that, it has been 20+ years since I took an HP scope apart .

ken
 
Ken you keep saying Hp scope... Am I missing something?

Thanks for the advise... I will go back and look and see if this thing unfolds in some sort of fashion...
 
This one has a beam finder button... use that to see if the knobs have been twisted to have everything off the side of the screen.

If that's not it, then start on page 3-28 with the low voltage power supply section and measure the outputs. If the -12v reference supply is missing then the power supply will not be working.

Next check the high voltage (CRT section) starting on page 3-33.

If the power supply is working, and you have the proper voltages for deflection and high voltage on the CRT then you need to check the Z axis amplifier section. It's what does the blanking on the screen.
 
Thanks Rj...

I had read that it might just be off the screen on another site.

But before I get to far ahead of my self. I need to figure out how to take it apart to fix the power cord first. I could burn down the house with it in that kind of shape.

So I joined this yahoo group...

http://tech.groups.yahoo.com/group/TekScopes/

In the hopes somebody can help me get this old girl apart to fix that first. Plus I see a fried cap on one of the boards.

Great advise man... That I will follow thru on
 
Ken you keep saying Hp scope... Am I missing something?

Thanks for the advise... I will go back and look and see if this thing unfolds in some sort of fashion...

Sorry, I had somebody walk into my cube and ask about an HP printer that I have at home while I was trying to put a post together. I had HP on the brain after that. I meant to say Tektronics. DOH! Multitasking sometimes has it's pitfalls.

Tek's generally come apart, but you need to watch for the side that doesn't have a lot of wiring. That is usually the side that comes off and it folds open. The side tha has the wingin is usually the "hinge" side. If you are pulling on the wiring, you are doing it wrong.

ken
 
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