HP calibration resistor out of spec

Hello Fred,

No need to trash them, they might be needed on video jobs. But they should label them clearly enough that anyone can distinguish 50ohms from others without their glasses on.

Regards, Joerg

I have had good results with some of the automotive hand cleaners when i had to remove the mess that old foam makes. I smear some on the mess and let it sit in the hot Florida sun for an hour or so, then use a hose to rinse it off. Some things only need one treatment, others take two or three.

Hello Michael,

I wonder if the trick would also work with the California sun. See, yours appears over the ocean but ours disappears over the ocean. But I don't want to hose off HP equipment ;-)

Repairing this 4191 is a pain (mostly on my lower back). Today I have the "pleasure" to take apart one of the samplers because that's where things look iffy. And I don't have an 18GHz scope as they recommend. Time to improvise.

Regards, Joerg

I removed the case or covers before cleaning them. It also worked on some old Burroughs minicomputer cabinets on wheels that I cleaned up to use as tool cabinets.

Hello Michael,

A friend in Europe did the unimaginable: He bought an old commercial grade communications receiver for a song at some flea market. It worked but was outright filthy. He put the whole thing in the dishwasher (!) and it came out almost like knew, not counting the scratches it already had. He let it dry out really good and it still worked.

Now I would never do that.

Regards, Joerg

Microdyne ran completed PC boards through a commercial board cleaner that was nothing more than a modified stainless steel dishwasher. They built telemetry equipment.

Joerg wrote in news:2IN4g.63809$ snipped-for-privacy@newssvr14.news.prodigy.com:

I used to give TEK scopes and other test equipment baths in a wash booth,and then into the drying oven for 3 days.You just avoid hosing down the transformers.

A good cleaning really helps make a unit work better.

"Michael A. Terrell" wrote in news: snipped-for-privacy@earthlink.net:

Dishwasher 'soap' is a very aggressive cleaner,especially on organics. It needs a thorough rinsing,though.

On 29 Apr 2006 22:06:43 GMT, Jim Yanik Gave us:

Water is a very aggressive cleaner, it just needs a SOAP to reduce the surface tension enough that it can undermine dirt, such as organics.

It is the WATER that does the job. The soap merely allows it to get to places it would not normally be possible for it to get. It softens the water, but the water is still the true workhorse. Especially hot.

We used a special citrus based PC board cleaner in the machine, followed by a rinse and being baked before going to the module line for testing. Spot cleaning was done with IPA and a few other chemicals.

Before you throw it away, ask me. I'll even lend it back to you.

Hello Joseph,

If the TenTec VNA would be satisfying industry cal requirements this decision would become much easier. But last time I talked to them there were no plans, it's geared towards the hobby market.

Anyway, somebody just offered me his HP4191A in case I don't want to spend more time troubleshooting mine. Problem is that was in another language NG and this unit curently sits in a lab in Europe. Let me know if interested and I'll send you his email address.

BTW, the Schiller Quote in your tag line still sounds a bit butchered...

Regards, Joerg