Dear Tom,

many thanks for your detailed explanation.

Today before my breakfast;-) I replaced two caps
a little choke and the destroyed resistor (I guess a value of 75Ohm)
by some parts of my ham box.
The second cap which was connected to the resistor which overheat was
shorted too but looks good from outside in contrast to the one which was
destroyed.
A quick and dirty solution for the moment until I get the proper infos.
This dirty solution was so far successful as I could see the spectrum of
the 300MHz test oscillator build in ;-)

Now I will check the docs in order to find out how to proof that the SA
is working properly.

I will keep you informed on further progress.

By the way I get some help from your good friend Barry WA4VZQ
via mail.

vy73

Markus



Am 20.04.2011 00:37, schrieb K7ITM:
On Apr 18, 11:56 pm, Markus Wolfgart wrote:
Dear om Andrew dear om Tom,

many thanks for your prompt replay.

Today before breakfast I start to fiddle out the connections from the
pcb to the parts on it.
I'm not ready yet but probably this evening.

But its true as you noticed that all tree caps are routed to the inner
layer (only three of them) with the pos. pol.

The neighbour of the burned resistor seems to be a coil
(vio/red/green/silver/space/brown) colour marking (72uH? I have to check
the meaning of silver labelling factor 0,1?).

The burned resistor is not directly connected to the destroyed cap but
to one of the others 10u25V or 39u10V.

As you mentioned the OPA labelled as PMI9017 - is this part comparable
to a OP07 (or OP27) ?
I have unfortunately no luck to find any doc in the web but some hints
that PIM parts were manufactured for AD in the 80 years and later on AD
take over this company.

I hope to fine more details this evening.

Many thanks for your help.
I will keep you informed on my progress.

Would be great to reanimate this HP8562B for ham purpose.

vy73 + tnx

Markus
DL8MBY

Am 18.04.2011 12:58, schrieb Markus Wolfgart:

Dear OM's

I'm looking for some help concerning a defective driver pcb for a
yig oscillator inside the mentioned device above.

see link: (http://www.mikrocontroller.net/topic/215840#2149959)

I'm looking for the proper value of the destroyed resistor ( 50 ohm) in
the lower corner as well as for the value of the capacitor.

Have any of you a link to the service schematic of the mentioned driver,
or could send me a copy of it.

Any help would be appreciated.

vy73

Markus
alias
DL8MBY

Addendum: the label on the op amp, PMI9017, is undoubtedly the date
code: 17th week of 1990. The 1826-1149 is an HP part number: all
common HP parts have a "4x4" HP number; ones special to a single
instrument or a few instruments may have a "5x5" number. Note that
the printed circuit board has a 4x4 number: 5062-0752. That suggests
to me that the YTO is used in several other instruments, though it
could also be the case that when it was made, the team _thought_ it
would be used in other places. I'd expect some of the boards in your
instrument will have 5x5 numbers beginning with 08562, showing that
they are used in the 8562. Many (most) parts with 4x4 part numbers
have one or more equivalent industry-standard part numbers; for
example a 316 ohm resistor could be purchased from any of several
different suppliers, all qualified to meet the requirements of the
particular 4x4 part number. But in some rare cases, a 4x4 number
refers to a part selected for especially good performance in some
area, and you couldn't be guaranteed to maintain performance of the
instrument with a similar non-selected "generic" part.

Cheers,
Tom