Re: Just got a tek 555 for free, and in need of some advice!

Bob Koller <testtech@...>

If you want to be really careful, slowly raise the mains voltage with a Variac if you have one. This will allow all those old electrolytic caps to reform slowly. this is about all you can do. You can keep the CRT intensity low to "soft start" the CRT, but I am not sure how much difference that makes. The caps can definitely benefit from re-forming, IMHO.

From: dutchbosstard
To: TekScopes@...
Sent: Wednesday, July 4, 2012 2:13 AM
Subject: [TekScopes] Just got a tek 555 for free, and in need of some advice!

So this past weekend someone was put an ad in up for a free "vintage tektronix scope" on craigslist in the middle of nowhere town of milford california. It turned out to be a complete tek555 scope on a cart with its power supply and cable. After talking to the guy, he has an engineering background, and was last using the 'scope back in 1995, before leaving in it in his storage shed where it sat until now.

I will put pictures of it up when i get the chance. From basically looking it over, mice had eaten up most of both the filter for the scope and the power supply, but there were no holes in either so i know they didnt enter the scope or supply. I havent powered this thing on yet, and before I do, I would like to know what all i should know about before i do. Since im just a young engineering student, I dont know much about tube equipment yet.

from what i hear, it isnt missing any internals. All the tubes are there but they're pretty dusty. i do not know if thats a problem. I also noticed that on the one plug-in that i can remember off the top of my head (the scope is temporarily in my friends garage) the 20mHz 4 trace type M plug in - I pulled it out and at a glance everything looked in place but i noticed from the soldering in the resistors that someone had definitely worked on it once before and i noticed it did have a short 4in long wire soldered to one of the resistors that was going nowhere. However i imagine the work that was done probably from the original owner, not the guy who gave it to me.

so, basically I am asking if i should be worried about just firing it up. is there anything I should inspect inside of it other just looking everything over inside and taking out the plugins and looking for anything obviously wrong, like a leaked out capacitor, burnt resistor, missing tube or transistor, missing connections, etc? I also heard that its a good idea that if a scope hasnt been run on a while, to power it up with all the intensity knobs turned way down.



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