No.111 - Tektronix 2215 Oscilloscope Repair 

Additional note regarding the transistor I swapped out. The BFR96S for the original BFR96: BFR96 Ic = 75mA BFR96S Ic = 100mA The DC current gain (dB) is a little less on the S version, but I cal'd that out. I thought it better to have that slightly better Ic in the hope it makes it a little more robust. You must use a matched pair, don't mix an S version with a non-S version as it unbalances the differential amp and one of the transistors will blow after a while.

I would have thought bringing up a switch mode like the pre-regulator slowly on a variac is a bad idea as it will send the control loop into a spin. If it had auto 240/120 selection even more so.

Very good videos! Only criticism Warning High Voltage should be at beginning of every video when working on mains/ power supplies/valves etc, I worked over 40 years on SMP, valves, HV business machines, p.a. Gear etc.! Yes I got bad shocks twice mostly stupid mistakes! i.e. examining motor field coils- I plugged in them instead of angle poise lamp and ended up against a door! Ouch!

What I would have given to be in with a chance of any kind of free scope when I was a young 'un, never mind a 60MHz Tektronix :⁠-⁠). Nice gesture, Ian - we need to encourage more youngsters into the field.

Even Tektronix used Rifas! Good idea to replace the IEC filter/socket. I had one of those go pop & let the stinky smoke out, in a Tektronix video signal generator.

Whats the typical manufacturer spec on reading precision of those voltages in those analog oscilloscopes?

I have a tek 2225 analog scope and i know it has a very small amount of horizontal jitter as it can not be visible in normal operations. But when i magnified the internal calibration scurewave to calculate rising time of that signal it can be visible. The isue is not quality of that signal because i have same problem when i want do same mesurement of signal rising time of my TDR circute. Intersting point is that this problem apear in first case i mean the internal calibration signal, just when slope switch of the scope in front panet set down . But in mesuring signal from TDR circuit acure eather the slope switch set up or down. Could you gess the issue is in which part of circutry ? In trigger and slope circuit or in horizontal amplifire ? TNKS

THat power supply board would have fired up nicely on its own to check all its voltages.

Nice. I have a 2213A which was my first oscilloscope :)

Subscribed for the accent brother.

Nice repair Ian. I'm not so young anymore so I have no chance of winning the 'scope.

The vertical deflection problem looked just like what I had on a 2225, but in my case it was a fried resistor. The service manual said they switched from 5W to 7W during the production run and the 7W replacements I ordered were a good bit larger than the fried-looking one that died so I guess that explained that!

Great repair and a good idea give it away to a youngster 🙂

Great troubleshooting! Nice job.

wait our you still giving out an oscilloscope??? i need one so bad

RF transistors for vertical deflection? DC voltage on vertical deflection!? - oh right, not a CRT TV - I may or may not have expected a nice saw-tooth to the tune of 50 Hz. Kids, bias is only good for circuits, not humans.

Nice video ! perfect for audio work would be very useful to me....... but A) I don't use twitter and .....B) I certainly can't get away as a young'un anymore not even in my dreams Lol ! very enjoyable as always....cheers.

I have a 2214 that has a problem of, when you turn up the trace intensity, it changes the amplitude of the trace on the screen! Sadly I cannot source a circuit diagram for it to help trace the fault. I'm not good enough to do it flying by the seat of my pants!

3:10. "made in haiti" ???? 🤔🤔🤔

The focus appears to be wrong... there are resistors that drop the HV for the focus control. These resistor are famous for drifting up in value, making it impossible to adjust focus. Suggest putting more resistors in series... so that each resistor will hold back less voltage and will be more stable over time.

I think everyone should have an analogue CRT scope, gave mine away years ago which I think was a mistake now. 😞

if i recal that pre regulator component uis an scr not a mosfet!

Awesome ! I did a similar repair, few years ago, on a Philips CRT digital scope which is nice to have in your lab..

Exactly the right mix of details and progress; great repair video.

Great troubleshooting, enjoy to watch

Had one at work in the 80's fixing arcade games. Glad to see this one made it.

Wow - memories. This was my first scope - well my employers! It was on my bench in the electronics dev lab at GEC Traction in Manchester - I want to say around 1982-3 ?

Ian: 👏👏👏👏👏👏👏👏👏👏👏👏👏👏👏👏👏👏

I have a 2215A that confounded my repair attempts over a year ago. A PSU fault remains after I fixed a few other things. I'll now go back and see whether your findings shed any new light, though the A version was a bit different. Thanks for taking us along with you.

Enjoyed the video, Ian. I don't understand how RF transistors were used. Would like to have seen a picture of them in circuit. Thanks! John

Very detailed explanation on troubleshooting and repair.

What a fantastic job. I'd love to have that analogue scope. Do you know where I can get one of those trim tools, I've been looking for a while now but no luck?

Hi!

Why are there resistors in parallel with the common mode coils? I have never seen that before, what are they doing?

I have this exact scope and need to change the RIFAs. Please provide a list of those that you found - reference numbers/values/specs/etc. would be great. Please and thank you! Much appreciated!