Tektronix 454 question
- Thread starter ReRibbon
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Help Support GroupDIY Audio Forum:
Generally the scope will have a front panel square wave output that you can use to adjust the probes, but will also give you simple test that it works.
JR
JR
There is a BNC connector on the right hand side almost all the way up marked "1V Cal 1kHz". Touch the tip of the probe (if they have one) to the center of that connector and adjust Volts/Div to .5 or 1, and Time/Div to .1ms. You should see a nice square wave. The craigslist photos don't even show a trace, but I suppose that could be due to improper settings and or lousy photos.
I just got a refurbished TEK 2465. I always cheaped out on scopes before just getting "working" ones. The working ones worked but I always had trouble getting the triggering to work without being fussy. This refurbished scope triggers like a dream. I'm thinking that the sweep sections on the other scopes weren't quite right. I'm very happy now. I should have spent the extra on a guaranteed one much sooner. The 2465 was $400 on the bay. Prices have come way down. The same scope from the same seller was $1100 just two years ago.
I agree, Paul. My Tek 465 died a month ago and it literally wasn't worth my time to fix it. I scored a 2235 that was NIST calibrated last year for $201 on ebay.
Go to BAMA, download the manual. There should be a Basic Checks page.
The main problem is that there are too darn many knobs and switches. The manual should give you a Basic Settings which will give you "a picture". From there, if the 'scope probe is grounded you get a horizontal line; if probe is fed from the CAL jack you should get a square wave (will have to adjust width and height); if probe is held by by a guy not touching ground, it should show a messy sine-wave (all the electric hum and buzz in the room).
Focus should work. Astig is a secondary focus. Do NOT turn BRITE full-up, keep beam strength somewhat below maximum (for best focus and also for good screen life).
The main problem is that there are too darn many knobs and switches. The manual should give you a Basic Settings which will give you "a picture". From there, if the 'scope probe is grounded you get a horizontal line; if probe is fed from the CAL jack you should get a square wave (will have to adjust width and height); if probe is held by by a guy not touching ground, it should show a messy sine-wave (all the electric hum and buzz in the room).
Focus should work. Astig is a secondary focus. Do NOT turn BRITE full-up, keep beam strength somewhat below maximum (for best focus and also for good screen life).
Andy Peters
Well-known member
ReRibbon said:
In addition to what's already been said, you really need to go through it and test all possible switch/button settings. That means testing all settings for the vertical (volts-per-box) and making sure that none of the settings are wonky. Make sure that when you switch the input coupling from DC to ground to AC that the signal doesn't vanish. All settings for horizontal should be good too. Make sure when you take the verticals and the horizontal each out of the "cal" state that the display doesn't go wonky. You might have to spend a lot of time cleaning switch contacts.
I had a 454, gave it to a friend who uses it to demo waveforms in his theatre sound class.
shaggy
Well-known member
150MHz bandwidth. An old (mid-1970s) but very solid scope. That was just about the last model Tek that you have any hope of repairing yourself. All discrete, and all the transistors are socketed(!) 1980s Teks had proprietary custom ICs and fragile PCB-mounted open-frame switches that are next to impossible to fix.
If you get it, just go over it and remove/insert the transistors (sockets and lead connection can get grungy after sitting for decades), and work the front panel pots and switches. If you're lucky, most of them will self-clean.
Dave
If you get it, just go over it and remove/insert the transistors (sockets and lead connection can get grungy after sitting for decades), and work the front panel pots and switches. If you're lucky, most of them will self-clean.
Dave
