Jim Yanik wrote:
"James Sweet" wrote in
news:x93Oe.2976$0U6.2125@trnddc09:


"satelitko" wrote in message
lkaboutelectronicequi
pment.com...
Is there anyone who have a service manula for this oscilloscope? I
bought used one, but found that an IC on fan motor board is missing -
so fan doesn`t work at all.
Regards, Gregor


ISTR that it was a 5-transistor array.
IIRC,the same chip was used in 400 series scope fan circuits(465?,485),they
both used the same Hall-effect fan motor.Also in some 7000 series
mainframes(78xx79xx,IIRC).

In later 2445/65 series scopes,that fan assy was replaced by a simple 12v
fan like used in PC power supplies.The rear chassis panel was modified to
accept the new fan. I would probably mod that 2465 myself if the fan was
bad,rather than try to find a IC and find the motor was bad,or do without a
fan;a bad idea.

--

It is as Jim said a 5 transistor array. A CA3046 or 3086 should work
well.

The letter series scopes ("A" or "B") have the PC style fan.

The non letter 24xx scopes have the Siemens Hall effect controlled
motor.
Same as 465/466/465B/475 and 7844/7834/7904A etc. The 7904 has no fan,
so it's really an ease for long hours work (less noise ,-) )

If you want to modify a 245/2465 for the PC style fan: Go and find a
different rear plastic; e.g. from a junker A or B model.
By not replacing the fan you will fry your hybrids sooner or later
(especialy the U800 IC for horizontal drive). Which means your scope
will be completely dead. Do NOT risk this.


hth,
Andreas