[Elecraft] Tek Oscilloscopes

[Robert Cochrane]

Apologies - this is slightly off topic, but I strongly support Don 
Brown's very informed advice on Tek oscilloscopes, and we will all 
need a decent scope one day.

The earlier "hybrid" custom Tek ICs with specialised architecture are 
no longer available and work arounds are difficult if not impossible, 
so cannibalism is often the only route for the earlier 
scopes.  Sometimes made easier by the modular construction, but as 
Don says, full re-calibration is an art.

I repaired and re-calibrated my Marconi sig gen from the same era, 
but I have no intention of opening up my Tek and have deliberately 
not obtained a service manual.

The 2445 / 2455 / 2465 range is to my mind the peak in the analogue 
range, with the same sort of operator feel as the K2.

There are several models, differing in bandwidth and on screen 
cursors and information, so check the exact model.  And get hold of a 
copy of the operators manual to understand the facilities - copies of 
copies are available on eBay and through specialist firms in USA and UK.

I have the "entry" 2445A 150MHz model which has been re-calibrated to 
within 3dB to 200 MHz and triggers past 500MHz on a simple sine 
wave.  Apart from bandwidth, it is almost identical to Don's 400MHz 
model.  It is also regarded by some as the most reliable in the 
range.  The A series only show either the twin horizontal or the 
vertical cursors at any time; I understand that the later B shows 
both at once (I have never needed this and think it would clutter the 
screen) and some say it is a bit less reliable due to bought in components.

Make sure you don't overload the input, particularly the very useful 
but also LV 50ohm input, which can cause terminal (i.e. fatal) 
damage.  Make sure the power selector is set to the right voltage (of 
course) AND the power lead is retained by a cable clip (there is a 
screw hole to fix one on the case) as they can be damaged by arcing 
if the power lead comes off during operation.

For the UK, I think it is better to buy on eBay from one of the ex - 
Tek guys who advertise regularly, who usually carry out full checks, 
offer guarantees and calibration of bulk S/H buys from institutional 
sources.  I suspect they have also have boxes of the some of the rare 
components too.  I can give a couple of names off - line.  The scopes 
sold over here are usually European manufacture, quality is good.

It costs more, but to me it is worth it.  UK prices seem to have 
risen as a result of demand from the European continent (particularly 
for the flagship 400MHz model) , so expect to pay a bit more than Don 
over here or go for the lower bandwidth models as I did.

73 Rob M0RAC
K2 3314

Robert A Cochrane
7 Lawn Terrace
Blackheath
London SE3 9LJ   UK

Tel (44) 020 8297 1978
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