Experiment: buying obscure obsolete IC via chip broker

[TerraHertz]

It is most likely a PAL16R4. There is the national semiconductor logo visible and the text 16R4.

Ah yes! Very likely. Thanks. It was late at night, and I didn't make that connection.

Contact the seller--OR just file a claim directly with PayPal for counterfeit merchandise.

Yes, that's today's chore. Pretty sure it will require a direct PayPal claim, as the seller was incommunicative in a way that makes me think they knew the parts were fake.
I have the full correspondence sequence. Hmm... though I suppose I should first give them an opportunity to refund, just on principle. And to see how they behave.

Do we think this is a full-custom (BrEnglish: bespoke) chip?
Or is this just one of their standard products with  HP's house-number on it?
Or a special spec/test version of a standard part?
Is it not possible to correlate the package and pin descriptions against their standard products?

The original switchmode control IC is an Exar product, with a HP part number. However there seems to be some kind of secrecy veil around it. Google says, of all the people with HP instruments containing these, no one has ever found either chip data or a source to buy them. This particular HP part number is skipped in all HP cross references I've found. There are rumors the part was used in some missile system, hence the secrecy. At the time it was designed and manufactured, the HP 54121T 20GHz scope system was export restricted and no schematics were available, so maybe use of a restricted part was considered a useful design obfuscation feature.

The above is why I find the large stock quantities quoted by multiple Asian vendors, fairly unlikley. But if I get my money back on this purchase, we'll see. Next attempt will refer to the writeup. Will other vendors back down, knowing they will be outed online if they supply fakes?

Writeup: http://everist.org/NobLog/20151112_planning_vacuum.htm#54120B_ps  (still to add checking and de-capping the fake.)
PS schematics: http://everist.org/NobLog/pics/20151112/sch_ps/HP_54120B_power_supply.htm

Incidentally, I've been dithering over buying a decent microscope digital camera head, since it's a lot of money (for me) and I can't decide among the various models available. Have been meaning to start a thread about that, asking for anyone's experience with the camera heads on my list. That's another thing to do today. Really have to pull my finger out on that one. I'm a bit snowed under a recent ToDo list explosion.

[all_repair]

It is Chinese New Year now.  It shall be a while, you shall get your non-reply.

[TheSteve]

Shame it was a fake. Do file a claim, escalate if needed. Request a refund only, they might try to offer replacement parts which will never arrive.

[TerraHertz]

Quick update. Better writeup: http://everist.org/NobLog/20151112_planning_vacuum.htm#unob

Vendor asked to refund, or expect payment reversal via paypal due to supply of fake merchandise.

[Susan Zhang]

Hello,Everyone

My name is Susan Zhang from New Strength,Co.My nature of the company is the dealer,I am a sales manager in our company.
Sorry for learning us in this case.
We are sells IC CHIPS 10 years in China,We explore the international market since SEP last year.
When we explore the market is rash and lack of experiences,We are making an apology in here to Mr Guy and every of the same trade work in electronic components.
We are only sells the stocks own us in China(40000 stocks),We can guarantee its quality.because the goods is own us,We checked everything is good about the goods before we bought it,But we have no idea with the stocks from another suppliers
Sometime we need to take the goods from another one and then sells to the customers,so the risk is very high,We dislike it
Thanks for the mail from Mr Guy to make us be right,we won't make business with them anymore
I have made a sincere apology in private to Mr Guy,I hope you will forgive us if you can

Make a public apology to Mr Guy and everyone in here
We will try to make to correct them and perfect our service

http://www.ic-trade.com/company/25970.html

Best Regard
Susan Zhang From New Strength Electronic.,Co

[rsee]

Sorry to see you had bad luck.  Great job on the decap work though!  It is always fun to see what is inside!