RESTORATION of TEK 7603 Scope w 7A18 amp + 7B53A timebase

[robrenz]

Thanks again all for all the kind words,   

It looks like I have some more work to do:
The readout system is giving bogus readings as the timebase reads 1000 faster than it realy is and the vertical amp is good down to 1V/div then is off by 100 on all settings below.

The beam intensity on intensified trace is too high relative to the unintensified trace.  Also seems to be some noise riding on the intensified section.

Fortunately I have the original service manuals for all the pieces.

[casinada]

Too much polishing made the electrons go much faster 

[robrenz]

After exchanging all the IC's on the readout board with ones from a working readout board, the readout still off. So I just exchanged the whole readout board from the other 7603 (I know that's cheating but its working now). I can try to figure out whats wrong later.

I checked all the supply voltages and they were in spec. including ripple.  I still see what looks like a very faint Z axis modulation on the traces. It is barely noticeable but I wonder what is causing it?  Any help gladly accepted 

I did the proper Z-Axis DC levels adjustment per the service manual but the intensified trace was way too bright compared to the normal trace. So I just adjusted the CRT grid bias until I got a normal difference between the intensified and normal sweep.
anyone know if this will be an issue?

[wkb]

Very impressive! 

It is now better than new!

[grumpydoc]

Rob, that is utterly brilliant work - you don't know how much I hate you right now

[casinada]

Rob,
The best place for help with the 7603 is the Tekscopes group at yahoo. I have a tek 7603 myself. I got it at a Junk yard 24 years ago and it still works very well. I only had to clean it. It even came with the cover   One of this days I will open it to clean it again.

[Oracle]

well done! impressive! 

you just remember me to clean my oscilloscope...

[saturation]

Most amazing results!  robrenz procedures should be of help to all, the photos show it all.  I've highlighted the key equipment used.

The main cosmetic issue was serious corrosion under the nickel plating on the front and rear frame bezels. The main covers were just dirty and needed some body hammer work from heavy items that gently bowed the tops in the perforated areas and some light dents. Magic sponges and simple green were extremely effective at removing the dust that very firmly attached itself to everything. Armor all was used on all the exterior plastic and vinyl parts. The plastic CRT filter needed a wet sand and plastic polish treatment to remove some mild scratches.

The main functional issues were the very dirty and corroded bnc connectors and the normal scratchy pots and switches. I disassembled the pots that were bad and ultrasonic cleaned all the parts in IPA. Then cleaned all the contacts and wipe areas with Deoxoit D100L on a soft wood stick. Clean with IPA again and lube the gold wipe areas with Deoxit G100l and the actual pot wiper with Caig Faderlube. The mechanicals were lubed with Triflow grease. The gang switches were flushed with IPA and then Deoxit D100L was blasted thru them with compressed air. The drum switches in the amplifier and timebase were disassembled and all the gold finger contacts were individually cleaned with D100L on paper pulled thru the contact area, cleaned with IPA and lubed with G100L.  I also replaced the power cord that was pretty stiff.

[billclay]

I always look forward to your posts and videos.  Your work is superb, as is the presentation and explanation of the process.  Can't wait to see your next project!

[felixd]

 :scared:AMAZING !

[e-doc]

Very impressive!   

[luudee]

I know this thread is 10 years old, but I enjoyed it very much, answered some questions I had.

By the way, I use small brushes and sponges that my wife buys at beauty shops. Specially all
those things they sell for eye and lashes, are particularly useful to get into the small center hole
of the BNC connector, for example ...

Cheers,
luudee