Tektronix 468

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synx508
Posts: 76
Joined: Mon Aug 21, 2023 6:13 am
Location: UK

Tektronix 468

Post by synx508 »

This Tektronix 468 with both service manual volumes and the operator's manual was unavoidable, at the rally. I was told that it had a bad timebase but what I wasn't told was that the person who reassembled it after deciding they couldn't fix the timebase had mangled one of the internal coaxial connectors rendering the horizontal output inoperative.
Once I'd bashed the connector back into shape the deflection was restored and on to the next problem, there was no triggering and no timebase activity at all. X-Y mode worked, so all was not lost. Power supply voltages seemed almost perfect.
I swapped the Tek ICs between the A and B timebases and this restored the A timebase and triggering, as expected the B timebase is inoperative.
The digital storage feature seems to work but there's a problem with the cursor knob, turning either way decreases the value, so the cursors roll off the bottom (V) or left (t) of the screen. Not very convenient. I'll stare at the schematic tomorrow to see if there could be an electronic reason for this but perhaps the switch is broken in some very strange way.
There are a few other problems, attenuators on channel 1 (again!), width of the trace seems inadequate and in non-storage mode at lower sweep rates the blanking is completely messed up, blanking beginning about a third of the way across the screen - again, not terribly convenient.
It looks stunning though, if you twist your head around a bit…
Image

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tggzzz
Posts: 1912
Joined: Sat Oct 22, 2022 8:17 pm

Re: Tektronix 468

Post by tggzzz »

Overall I quite liked my 468, but not enough to prevent me flogging it.

The analogue part is a 465B, which is a good start.

The digitising part is slow but not based on a CCD sampler, thus avoiding slow sweep speed aliasing problems. Indeed, it even has an "envelope detect" mode that wouldn't reappear for several decades.
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