Vishay hermetic foil resistors on ebay - Page 1
Forum section: electronics / projects

author: splin
author_rank: Frequent Contributor
timestamp: December 13, 2015, 10:09:25 pm
content: There is a Chinese seller, hifi-szjxic, offering various Vishay foil resistors on Ebay. I have no real concerns buying the relatively cheap unsealed parts with short legs which are obviously reclaimed such as S102Ks and have actually bought some previously without problems.The hermetic parts however, such as VHP202Z, are much more expensive at $30+. Suspiciously though, out of 168 such parts on sale *all* have full length leads which would imply they are unused. How come there are no short lead reclaimed parts? I wonder if some may have been pulled from PCBs, the cans un-soldered and new leads fitted. I expect it wouldn't be hard to do and would enhance the value. I've attached a couple of example pictures showing different types of seals.If they are doing that, there is no guarantee that the resistor inside hasn't been swapped for a cheap, 2$ part - although they presumably would have to match the marked resistance which would be tedious for the higher precision (.005%) parts. The oil fill may also be lost. Worse, the thermal shock of resoldering new leads would probably restart the long term ageing so the drift may be high for some time.I did find the third picture which initially confirmed my suspicions until I read the datasheet for the HS555 which states:'VHS555 is the hermetically-sealed version of the S555, MIL style RNC90Y.'so is presumably genuine. Does anyone have any opinions as to how likely these are to be genuine parts? Anyone bough any and done any decent measurements on them, particularly wrt long term stability?

author: plesa
author_rank: Frequent Contributor
timestamp: December 13, 2015, 10:36:30 pm
content: I will not buy them. It just remind me the thread related to fake LTZ1000.....This seller has been mentioned in this threadhttps://www.eevblog.com/forum/projects/ultra-precision-reference-ltz1000/725/So maybe they are really genuine, but the reason why they are on ebay as brand new is not clear to me.In case they are not meeting spec I expect original customer will return them to Vishay instead of selling on eBay.

author: acbern
author_rank: Frequent Contributor
timestamp: December 13, 2015, 11:11:46 pm
content: I saw thoste two, been there for quite a while now, not much sales. Sure, why would anyone buy it if an original one from VPG is only slightly more?

author: TiN
author_rank: Super Contributor
timestamp: December 14, 2015, 12:35:07 am
content: Coz it's much faster perhaps?I got 10K+10K hermetic network from them for my 3458A repair experiments.Works well, looks like new.I can post pics if anyone need.

author: ltz2000
author_rank: Regular Contributor
timestamp: December 14, 2015, 04:55:02 am
content: But where to get those hermetic "crystal" cans that Vishay uses?Easy to find 30 years ago, but not anymore.

author: splin
author_rank: Frequent Contributor
timestamp: December 15, 2015, 12:23:19 am
content: Quote from: butterfly on December 14, 2015, 09:05:43 amI tried to get a quote for 2 x 10K VH102Z resistors direct from Vishay - the website clearly states that there is no minimum order quantity. Surprisingly they actually took the trouble to call me but not very surprisingly they weren't interested and politely directed me to a UK distributor Charcroft Electronics. I called them and they took the details of my inquiry, but presumably they aren't interested either and filed it in the bin as they haven't bothered to get back to me.I wish they would simply state at the outset that they aren't interested in piddly little orders and not waste everybody's time. I'm not sure I can be bothered to contact any more distributors hence my interest in Ebay sellers. I'd be amazed if I could get a sensible price for just two parts from any of the specialist distributors given their overheads even if they were willing to supply. None of the major distributors stock these although Newark does quote $47 for qty 1, 1K .05% VH102Z. That would probably double when shipping, VAT and customs handling charges are included.Do you really think I could get one or two 10K 1% VH102Z or VHP101 for less than $35 each from anywhere other than Ebay? They would (hopefully) be genuine parts but wouldn't be old stock with the benefit of years of ageing to reduce the drift.

author: TiN
author_rank: Super Contributor
timestamp: December 15, 2015, 04:16:48 am
content: You can contact VPG again, pointing that distributor tossed your request to bin, and they will likely fix it for ya. At least that was similar case during my order last year (bunch of resistors in 1-5pcs qty, for 1.8K$ though).

author: TiN
author_rank: Super Contributor
timestamp: December 15, 2015, 10:11:36 am
content: Depends on region still. I had contact from Israel, and later with their distro in Japan.