Another thumping great high spec Tektronix 'scope. I've not yet sussed
the difference betwen this 'B' version and the previous 'A' version.
This one is fitted with the type 1A2 dual trace plug-in amplifier, this particular example being built at Tektronics' Guernsey (Channel Islands) plant. Although this amplifier has 13 tr*ns*st*rs, there are a couple of Nuvistor type 7586 valves up front, kept company by a solitary 6DJ8. The Nuvistors are acting as input amplifiers, tr*ns*st*rs of the time presumably being far to wimpy to give both a high input impeadance and speed.
The power supply is sequenced so that after first switch-on only the valve heaters are lit. The HT supplies subsequently switch on after a delay of one or two minutes. This process is probably controlled by the funny little "valve" shown opposite. It looks like a pair of relay contacts but there is no coil. Instead there is a heater (the little white blob on the left-middle of the picture), the heat from which gradually bends the bi-metal contact. Since we are relying on thermal warm up the assembly no doubt needs to be placed in a vacuum, hence the glassware. I'm guessing that this device in turn switches a more conventional relay.
It may be a relay but does it qualify as a valve since it does have a heater :-)
|SERVICE DATA||Propbably very similar to the 545A, for which I have a manual. You can download a copy of the 545A's manual from the service data page.|
|CURRENT STATE||Almost complete, and with a good condition set of handles. Strangely a connector has been removed from the back of the case, and whilst some of the disconnected wires have been insulated with gaffer tape, some are just left dangling. I wonder why.|
|WHERE FOUND||A donation from Terri Martini.|
Transistors. Boooo ! Hissss !
Loadsa valves. Hoorah !
Advert from October 1965.
Link to larger view [194K].
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27th November 2006