Actually Hitachi sold HGST to Western Digital an American HDD company.
But if beer got into the small HEPA breather filter hole, too bad but if it just got on the circuit board. good news. low residue isopropyl alcohal and 24 forced air drying time will cure the problem. Beer has a dielectric constant due to water of about 60x air, which may cause crosstalk when on signals . If no click-click -click of death sound after startup, then Spinrite will fix it if the alcohal doesn't... then if neither works, buy a bottle of good scotch and douse your tonsils with it.
What do you mean by this?Then while waiting for it to dry. activate your spam filters on email.
Cap distortion is all about the dependence on ESR and voltage drop on change in capacitance with bias voltage. Y type Ceramic caps are the worst. COG are the best in ceramics for this attribute.
Old axial tanalums were high quality and many were rated for high rel quality when used in a design where the source and load impedance was greater than ESR ( such as audio applications , & filters or low current apps, but poor with ESR of cap was dominant in a high current app, meaning high ripple current and power dissipation and risk of thermal runaway.
Although never specified, all electrolytic capacitors can safely handle 10% rated V in negative bias.
(Note again.... "Electrolytics" includes ALL Tantalum wet or solid) common mistake to exclude them or say electolytics AND tantalum
Didn't that make the sound a little rubbery?....................
My first audio amp was made with germanium output transistors, OC28s, and any components that came out of the box. It sounded subdued to say the least, compared to valve amps that is. It came alive with a conversion to silicone, 2S026s,.....................
I was thinking of some other implants.Didn't that make the sound a little rubbery?
High value, high voltage ceramic caps really don't like it when a pc board flexes. A 6" x 9", 0.93" thick, 6 layer, 1 kW power supply board is not exactly flimsy, but those caps were not happy. Had to add stiffening bus bars down the long axis, but the bars improved some of the power handling so they were a net plus.
ak
No. The wet slug tants have enough internal impedance to limit the current to a safe value so you can connect them to an "infinite" current source and they won't blow up.Doesn't that apply to any capacitor by definition.
No, they were MIL certified. The solid Tantalums simply can not be charged from an uncontrolled current source because they can blow up. It was a well known characteristic which is why they did not allow their use in designs where the current was not controlled. In other words, you could not use them on a power bus or in our case as switch caps because the start up surge current might blow them. Sprague tested a bunch and culled out the ones strong enough to handle it for us and we used those. But it was a well known failure mode due to surge current.I know this sounds like a sweeping statement, but were the particular tants you were using a bit suspect?
Exactly. The ones I was referring to were the early 80's vintage.The Mil-std-Hdbk 217 was clear about Tantalum reliability with the ESR of the attached circuit and surge currents where the failure rate factor rises rapidly with lower driving impedance to old Tantalum caps.
We used a lot of surface mount tantalums on our switcher designs at Nat Semi in the 90's and they were reliable enough. Really had no choice because there were no small size low ESR aluminum electrolytics available at that time and the large value ceramics had not yet been developed. Once they came out with the high value (low voltage) ceramics, we went with those for most applications.Since the 90's as I referenced in #55, the chemistry has improved in Tantalum's which now serve as more reliable than Alum dielectric. e-caps.
Although never specified, all electrolytic capacitors can safely handle 10% rated V in negative bias.
(Note again.... "Electrolytics" includes ALL Tantalum wet or solid) common mistake to exclude them or say electolytics AND tantalum
That's not my understanding. I thought it was more like a "zener breakdown" type of condition where you had to limit the reverse current to a very small amount. I think if you actually force 10% of rated voltage in reverse (like from a power supply output) it damages the cap.Although never specified, all electrolytic capacitors can safely handle 10% rated V in negative bias.
No. The wet slug tants have enough internal impedance to limit the current to a safe value so you can connect them to an "infinite" current source and they won't blow up.
No, they were MIL certified. The solid Tantalums simply can not be charged from an uncontrolled current source because they can blow up. It was a well known characteristic which is why they did not allow their use in designs where the current was not controlled. In other words, you could not use them on a power bus or in our case as switch caps because the start up surge current might blow them. Sprague tested a bunch and culled out the ones strong enough to handle it for us and we used those. But it was a well known failure mode due to surge current.
Some other types also have surge current specs not to exceed: I remember the metal poly caps had a "dV/dt" rating which translated to inrush current (I/C) rating. They also have very low internal impedance.
My understanding from the Vishay documentation is that solid tants will take a maximum of 100mV reverse without damage and with normal performance.That's not my understanding. I thought it was more like a "zener breakdown" type of condition where you had to limit the reverse current to a very small amount. I think if you actually force 10% of rated voltage in reverse (like from a power supply output) it damages the cap.
Yes, I did know that WD had taken over HST, but as far as I know they are still operating autonomously
No beer got into the disk chamber and the heads are correctly parked. Also the platter spins quite freely.
The problem is the platter does not spin up
..... spec
That's not my understanding. I thought it was more like a "zener breakdown" type of condition where you had to limit the reverse current to a very small amount. I think if you actually force 10% of rated voltage in reverse (like from a power supply output) it damages the cap.
That's about what I remember as well. Very small reverse voltage tolerance before damage.My understanding from the Vishay documentation is that solid tants will take a maximum of 100mV reverse without damage and with normal performance.
spec
Interesting. Maybe the new ones are more robust than the old ones. I never tried reversing the voltage... at least, never intentionally.A Vishay FAQ document does say that a short duration reverse voltage is tolerable: (page 5 lower/page 6 upper) https://www.vishay.com/docs/40110/faq.pdf.
'Solid tantalum capacitors are capable of withstanding short duration peak voltages in the reverse direction limited to 5 % of the DC rating at +25 °C'
It also describes the connection of solid tants back to back to handle bipolar signals- this topic was discussed in the original part of this thread.
spec
Thks for explaining that so clearly. I get what you mean now and what Tony meant with his reference to the MIL handbook.
I can also see the logic of it, but am intrigued because I can't remember such a severe problem with solid tants and have never experienced it either. Out of interest, you don't have a document link describing the limitation? I don't have access to MIL specs anymore.
Quite a few components have dv/dt limitations which often get ignored.
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