On Sun, 21 Apr 2013 18:20:42 +1000, Trevor Wilson
wrote:

On 4/21/2013 4:43 PM, Phil Allison wrote:
"Trevor Wilson"
Phil Allison wrote:

** So the thick plottens .......

Seems there is disagreement between the manual and the labelling on the
back.

A "T 6.3" amp fuse is too big for a tube scope - but an "F 6.3" amp
fuse
would be about right, given the inrush surge of the circa 200VA supply
transformer.

**Don't be too certain. My second CRO was an Hitachi copy of the Tek 545A.
It was a massive, heavy, noisy, hot bugger. So close, was the copy, that
the Tektronix service manual was perfectly suitable for fault-finding and
operational needs. FWIW, the only major difference between the Hitachi and
the Tek was Hitachi's use of 2% tolerance resistors throughout the entire
CRO (except for high precision areas). Tek used 10% or 20% tolerance
resistors throughout. The thing used a full RLC delay line with 20 or so
valves. The vertical amplifier valve filaments operated in a series string
of (as I best recall) 120 Volts DC. Regulation for various circuits
(including heaters) was via 3 X 6080 dual triodes. The thing ate them. It
had a 200mm fan in the back and consumed 500 Watts under normal operation.
Great in the workshop during Winter. Not so good during Summer. My
subsequent CRO was all solid state.

A 6.3AT fuse, for 117VAC is within possibility. I've got a manual for it
somewhere.


** Here is a pretty good pic of the insides of a 545B.

http://www.barrytech.com/tektronix/v...k545bright.jpg

The AC tranny looks like it *might* be 500VA - but I expect Tek would use a
conservatively rated unit with a low temp rise.

If the OP would care to measure the primary resistance - I can say for sure.

**I found my 545A manual.

Power consumption is rated at 500 Watts. Weight is 65 pounds.

Fuse ratings:

6.25 Amp Slo-blo 3AG for 117VAC 50Hz
6 Amp fast blo 3AG for 117VAC 60Hz
3 Amp fast blo 3AG for 234VAC 60Hz
3 Amp slo-blo 3AG for 234VAC 50Hz

It's an interesting old CRO. I loved and hated mine in equal measure.
After I sold it, I bought a BWD, which I then swapped for a Tek 465B.
The 465B was boring. It did everything flawlessly and never gave me a
minute's trouble in more than 20 years.

The manual for the 545A occupies 50MB. I can post if you wish.
On the advice of several folks here and in the basic electronics group
I bought a used 465B 'scope several years ago. You are correct, if
exitement is fixing a 'scope, the 465B is quite boring.
Eric