Newly aqcuired Tektronix 2225 - Page 1
Forum section: electronics / repair

author: vferdman
author_rank: Contributor
timestamp: May 09, 2024, 02:09:11 pm
content: Hello, there. My first post here. I have been into electronics since my childhood in 1970's Ukraine where I assembled and tested many a radio receiver with my friends and generally geeked on solid state electronics while my dad had a side gig repairing tube TVs of soviet manufacture. In 1980 my family and I, as a teenager moved to USA where I graduated from university with a BSEE and have worked in US electronics industrial environments for many years until I began working more in software/firmware signal processing industry. I "grew up" on the likes of side button Fluke meters such as 8060A and Tektronix scopes, of which I have seen and worked with all ranges from simple desktop models to large cart beasts with plug-in modules and Polaroid camera attachments. I am no stranger to analog electronics and measurement equipment. I was in the labs when things were beginning to go digital and "Digital" was one of the names of our computer systems. In fact many of my friends worked at Digital at one time or another.So, recently, after watching Dave's awesome video about Tektronix 2225 scope I have decided to try one. I do some vintage audio equipment restoration as a side thing. Old receivers and such. I have an old HP 1220A scope that still works enough for my purposes, but after watching the video about Tek 2225 I felt nostalgic for the old Textronix look and feel I learned my scope skills on. So I found one on eBay for about $150 shipped in very good shape. Yes, the days of $50 scopes are kind of gone and I really wanted the 2225 for some reason, not sure why. Probably because of Dave's video. In any case, I got it and it is in very good cosmetic shape, though very dusty inside. Things looked ok, but the usual noise on the trace, which I guess is very common to these scopes. Also, channel 2 had problems with trace stability. It would be ok one minute and then start floating off screen in vertical direction until it was gone and I couldn't get it back. After opening it up and gentle percussion of the socketed opamp chips I realized that the CH2 chip responded to percussion with a chopstick. So I pulled it and cleaned the contacts of the socket and re-inserted it and problem was solved. Very stable trace now and does not respond to chopstick tapping. Great. Now I am on to replacing the safety caps, of which there are only two I can see and both are Y 2200 pF. I checked the voltage rails and they look ok with only slightly out of spec on ripple in some. I ordered some new electrolytic caps to replace on the power supply and voltage rails. Hopefully will get this puppy operating properly. As of now it works ok besides the noisy traces that sometimes straighten out and become perfectly smooth. The screen is in great shape, no burnout (I have seen burnt out screens in labs!), bright and crisp. The scope is surprisingly light and the knobs do not have that amazing Tektronix heavy duty clicking feel. It seems to be a budget machine, but a very well designed and built one. Mine is made in England.Anyway, I just wanted to write my first post and share my experience of obtaining a vintage piece of equipment that brigs memories of youth to me. Thank you for a wonderful forum and a great place to "hang out" for my electronic fun.--Vladimir