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Being an EE with manufacturing, parts buying and engineering experience, these caps didn't even make it past check-in against the invoice on Receiving
they were that badly oxidised- so badly I could see it thru the packaging. Hand soldering, an inconvenience perhaps. Manufacturing? Possibly a real problem
if there are solderability issues. the oxidation was so bad I had to scrape it off with a hardened steel ruler to photograph it. Drawing the leads thru a cloth had no effect.

I contacted Vishay who said they bought and re-opened the old Sprague plant and were producing (something-whatever) and thats why they were advertised "Vishay-Sprague"
by Mouser, ALTHOUGH... no info on "Sprague" parts appeared on the Vishay site. Vishay said the date codes were 2018.

The Rep also said that this level of oxidation is not consistent with the date codes, which admits fraud. I dont know for a fact that fraud is ocurring, BUT
counterfeit goods from China is a plague these days. Its an absolute plague in the nuclear industry, so bad that DoE issued a inch-plus thick advisory
text for the Hanford site warning Engineers and Purchasing to carefully inspect goods.

I suppose its possible that old stock 'cans' (drawn cups/leads) were used in modern production- i have no way of knowing.
The date code is not necessarily reliable. Its printed on a heat shrink tubular sleeve. It can be forged easily. Maybe they
had old-stock caps and printed a? new label?

A 3 cent label, or throwing away a 50 cent old cap? Again, not saying Vishay did so, but it would be easy to do and to hide.

I do know from a LONG time riding a test and high volume repair bench to never trust an old electrolytic. Ive seen too many short, leak and explode and do circuit damage
especially in older gear with pass-transistor regulated supplies. One cap exploded and ended up buried in the false ceiling 10 foot up.
Used to see 'lytics that shorted destroy power transformers to fill the shop with smoke.

Power transformer / pass transistors, 200$ plus or not available. New caps? 50-ish?.

Mouser denied it six ways from Sunday but refunded my money. Vishay admitted the leads werent right. Both denied counterfeiting.
Vishay said Mouser didnt have counterfeit parts. How would they know?

I bought all new caps from DK for half the cost. Just more hand-tuning by testing and assembling combinations of the correct values/tolerance.
Trading time for $.

interesting trivia point- the 1100 uF NP cap in the '651 was an 'aerospace grade' part, rated at 200,000 feet operation by an old Sprague document.
It was odd that the end-plug was very thick with a hard plastic cover, and the 'anode-end crimp' was extra deep and wide... and only a 10V unit.

1. I had a manual problem with my 651B, Found several manuals which had portions with teh same circuit boards as my unit and that was good enough to get by.
2. Barring blowing any of it in sensitive circuits such as open air variable caps, and having a DRY air stream (do NOT use wet compressed air) blow it out. Maybe with an intert gas duster can such as sold for computer keyboards.
Its possible to force moisture in circuits where it wont come out without heat.
3. Welcome to Oz. Tube gear is a specialty of mine. Its a particular problem. Several steps in general:

In general, for all tube gear:

a.) Replace ALL capacitors- electrolytic, tubular paper etc. Theyre probably 50-70 years old. Old caps are monsters waiting to do circuit damage. Ive seen many blow up.

b.) Check ALL bias resistors around each tube. A grid resistor going up in value can destroy a plate resistor or do damage other components or a tube.

c.) Its vital to clean tube pins. No one does it. I remanufacture old Drake ham gear and one of the first items is to spend two tedious hours with 600 grit sandpaper sanding the hard black oxides from the tube pins.
The pins were shiny when new (have replaced lots of them). The cleaned pins will scrape oxides from the inside of the socket pins, so don't do anything to a socket (unless its broken) except maybe spray some
cleaner thru them. Oxidised and bent tube pins can cause erratic operation a/o noise blamed on other circuit problems.

d.) high voltages, of course, are a problem. One can get dead working on tube gear. Learn/Practice the 'one hand in the pocket' rule around tube voltages.

e.) H fields. Build an E field generator to cancel them out.

f.) CRITICAL. Tube gear was made in the "107-115 VAC" AC line voltage era. Vacuum tubes use filaments (heaters) that are very sensitive to filament current (its a current vs. temperature square -function thing).
I just rebuilt a 1990s oscilloscope in which the 4 power supply regulator transistors were screaming hot (burned my finger touching the heat sink)- all because the AC line voltages here now
go to 126 VAC, on a scope intended for 115VAC max. I put a 15 ohm, 5W resistor in series with the power transformer and cooled the heat sinks down to 86 degrees F. Excess line voltage
can destroy tubes, if too high, shorten heater/cathode life, or too low, cause cathode poisoning. Many tubes require 5% filament voltage regulation and if operated from the AC line, may have no regulation built in.

Hi all,
I am working on getting an HP 89441A up and running (I am trying to measure the multi-path interference of received ATSC TV signals). Before I can dive into it, I need to gather the appropriate cables to interconnect the RF and IF sections. Most are straight forward (BNCs, a db-9 serial cable, etc) but the adapter needed to connect the reference output to reference input on the RF section is a bit, well, weird. According to Keysight Find-A-Part it is HP part number 1250-1499. Googling that part number brings up little in the way of sources, but indicates that it was also used on the 8590 series of spectrum analyzers. Taking a look at the back of my 8591, I could see that it indeed has one which is pictured below. Now the question is where can I get another one? Or, if I can't, will an ordinary BNC jumper work? Why does it need to be this special 1-piece adapter?




Thanks in advance,
Matthew D'Asaro

P.S. I bought the 89441A from a "reputable" surplus equipment dealer and paid $285 for freight service from LA to Seattle for it so it would arrive in good condition. It arrived strapped to a pallet but badly damaged because their ^*&#*&@ shipping department didn't bother to put a single bit of packing material around it. The RF and IF sections were literally placed upside down on top of each other in a bare cardboard box! The box arrived more or less intact, but the unit was not so lucky... I am working with the seller for a partial refund (I don't want to try to ship it back and neither does the seller) but really, people...

Attachments:

• Missing Adapter PN 1250-1499.JPG