On 12/23/2012 12:34 AM, Max Robinson wrote:
It's really very simple. The center conductor of the connector goes
through
a 53 ohm resistor to one side of the pickup coil, the other side of the
pickup coil goes to the sleeve. The center conductor also goes through
the
series combination of a 53 ohm resistor and a variable capacitor to the
sleeve. The capacitor is designated as c37. The two resistors are
designated as R58 and R59. I can't find these listed in the parts list I
suspect that HP probably sold the entire attenuator assembly as a single
replacement part. A DC measurement across the output connector should
show
53 ohms. I know this is not a standard value but that is what the diagram
says. My 608 shows infinity. That's not a good sign.
Regards.
Max. K 4 O DS.
Email: max@... <mailto:max%40maxsmusicplace.com>
/snip/
I was contacted by one of the readers of this thread who pointed me to a
pdf manual for the 608D. It's at
The description and part number of the resistors is as follows:
53.3 ohms ±1% 1/8 Watt carbon film. HP p/n 0721-0006. They list the mfr
as 19701, but I can't find a code-to-name list anywhere in that manual
to say
who the manufacturer actually is.
I'd guess that if you can somehow find a source of 1/8 W 1% carbon film
resistors
made by anybody, they would work. (I believe these are old-style
resistors with
axial leads, not surface mount or anything weird.) I think the warning
about not
overheating them is to keep them from changing value.
The capacitor, C69, however, from the description, is definitely weird!
--doug, WA2SAY
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