[Test-Equipment] HP 141 analyzer low gain

[Arthur Shulman]

I had forgotten about the amp in the IF plugin, Gary. But it turned out not to be the
culprit in my case.
There must be a fair # of extender cables out there, but I've never been able to
purchase them, except as a custom set, cost abt C$400. I would certainly be interested
if an owner would RENT them out to needy individuals for, say, a month. With a deposit,
of course, same as any rental. Then we could both get our gear fixed.
I suppose I should approach my Cal Lab and see if they would be interested in selling
obsolete cables! Ha!
If you can easily measure the gain down thru the amp & mixer chain, let me know what
you find. But do first try to find out in which plugin the problem lies.
Arthur

Gary Schafer wrote:

> Arthur Shulman wrote:
> > I had exacly the same problem with my 141T & 8445B, right down to the 20db loss
> > of gain. It was not the mixer, but low gain in the 50Mhz amp that outputs to the
> > IF section. My repair shop advised it was not worthwhile to continue the repair
> > due to the labor involved in dissasembly, so I replaced the RF section with a
> > known good unit. Has worked perfectly since, & I have the old module, still
> > unrepaired by me.
> > Suggest you try to borrow a different RF section, any range, and determine by
> > substitution if the problem lies in the RF or IF plugin. Then you can decide what
> > to do next. I think servicing this unit is almost impossible without the extender
> > cables, & I highly recommend you consider that if you find the problem requires
> > extensive dissasembly.
> > I seem to recall that the amp with low gain was buried beneath a mass of other
> > circuitry & hardware & was impossible to access for direct measurements. It was
> > possible to measure gain loss around that block, however, & that's why I feel
> > confident about the diagnosis, despite the fact that I was unable to determine
> > the exact failed component.
> > Please let me know what you discover, & good luck!
> >
> > Arthur Shulman VE3ZV
> >
> >
>
> Thanks for the tip. Another fella suggested the same thing, the 50 mhz
> amp. There are two of them. One is on the output of the RF unit. Not
> much too it and easy to get at. The next one is in the IF unit and looks
> like it is buried.
>
> I will have to see if I can find a connector to check at the output of
> the RF unit. It is smaller than an SMA, can't recall what type it is.
>
> Wish I had a set of cables!
>
> Thanks,
> Gary  K4FMX