494 and 2756 Spectrum Analyzer questions...

ulf_r_k
 

1st question.

I have brought a 494 analyzer back to life.
Except for the Xtal filter box on top of the
CRT, the instrument performs OK.
The filter box does not show any temperaturerise when in operation with cover off.

Looking in KE5FX service notes, the box
must be opened in order to replace the transistor.

Any suggestions about the best way to open it in
a non-destructive way? Put it on a hot boiler
plate and remove the cover when the tin melts
or use brute force making the cover unuseable?


2nd question.
I have also repaired a 2756P with various problems
and the instrument does now work.

I am just a bit puzzled by the fact that there is only a very small vent intake on the left side of the cabinet.

After some time, the rear end with the integratedheat sink gets to hot to touch. The Bueler fan
runs at highest speed. Other 49x analyzers that
I have used over the years does not even get
close to this high temperature. Easy fix
would be to add extra vent intake(s). Did Tek
ever made any modifications to the cabinet?
Cheers
Ulf KylenfallSM6GXV

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