Hi all,

Is this okay? I'm talking about replacing electros that have been in
service for like 30+ years and which have a rep for failing by then
(Frako caps) with old but unused electrolytics; so called "new old
stock" caps of reputable manufacturers of the same spec. I can't see
an issue with this but am no expert so.... what d'yall think?

Dan.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Monday, August 28, 2023 at 7:29:09 AM UTC-4, Dan Green wrote:

Hi all,

Is this okay? I'm talking about replacing electros that have been in
service for like 30+ years and which have a rep for failing by then
(Frako caps) with old but unused electrolytics; so called "new old
stock" caps of reputable manufacturers of the same spec. I can't see
an issue with this but am no expert so.... what d'yall think?

Dan.

It has been my experience that electrolytic caps of a certain age are as likely to fail just sitting on a shelf as in service. I suggest you purchase modern, fresh caps of the proper size, voltage and style from a reputable source made by a reputable
manufacturer. Why risk it?

Peter Wieck
Melrose Park, PA

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Mon, 28 Aug 2023 12:29:03 +0100, Dan Green <dhg99908@hotmail.se>
wrote:

Hi all,

Is this okay? I'm talking about replacing electros that have been in
service for like 30+ years and which have a rep for failing by then
(Frako caps) with old but unused electrolytics; so called "new old
stock" caps of reputable manufacturers of the same spec. I can't see
an issue with this but am no expert so.... what d'yall think?

Dan.

In my experience duff electrolytics are usually obvious from the
electrolyte ooze. I was fooled once by an old Leo3 computer power
supply unit that had four 500uF electrolytics in parallel. It smoothed
well until the last one failed.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Mon, 28 Aug 2023 05:57:32 -0700 (PDT), "Peter W."
<peterwieck33@gmail.com> wrote:

On Monday, August 28, 2023 at 7:29:09?AM UTC-4, Dan Green wrote:

Hi all,

Is this okay? I'm talking about replacing electros that have been in
service for like 30+ years and which have a rep for failing by then
(Frako caps) with old but unused electrolytics; so called "new old
stock" caps of reputable manufacturers of the same spec. I can't see
an issue with this but am no expert so.... what d'yall think?

Dan.

It has been my experience that electrolytic caps of a certain age are as likely to fail just sitting on a shelf as in service. I suggest you purchase modern, fresh caps of the proper size, voltage and style from a reputable source made by a reputable

manufacturer. Why risk it?

Personally I've not had any problems with NOS electrolytics provided
they were sourced through RS or suchlike originally. But YMMV.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Monday, August 28, 2023 at 8:25:21 AM UTC-4, steve1...@outlook.com wrote: I was fooled once by an old Leo3 computer power

supply unit that had four 500uF electrolytics in parallel. It smoothed
well until the last one failed.

The first time my Tek 7603 mainframe crapped out, one of the secondary supplies was quite low. This unit had like 6 huge Mallory caps in parallel and I figured it couldn't be the caps, but like yours, it turned out they were all open when I used my old
B&K to troubleshoot it. All six. They must have been dying off one by one with absolutely no evidence seen on the trace until the last one croaked. I replaced just one of them to get me going and used it several years like that until another group of
caps did the same in a different secondary of the power supply. At that point, I ordered all new electros and recapped the whole power supply.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Monday, August 28, 2023 at 7:29:09 AM UTC-4, Dan Green wrote:

Hi all,

Is this okay? I'm talking about replacing electros that have been in
service for like 30+ years and which have a rep for failing by then
(Frako caps) with old but unused electrolytics; so called "new old
stock" caps of reputable manufacturers of the same spec. I can't see
an issue with this but am no expert so.... what d'yall think?

Dan.

Years ago, I tossed out my NOS electros because testing them was uncovering some leakage at voltage. I don't recall the brand names if you're wondering that but brand new quality caps are so cheap that it didn't make sense for me to use the old ones.

For temporary work or for something that only has to last another small handful of years at most? Go ahead as long as they don't show leakage or abnormal ESR.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 28/08/2023 9:29 pm, Dan Green wrote:

Hi all,

Is this okay? I'm talking about replacing electros that have been in
service for like 30+ years and which have a rep for failing by then
(Frako caps) with old but unused electrolytics; so called "new old
stock" caps of reputable manufacturers of the same spec. I can't see
an issue with this but am no expert so.... what d'yall think?

Dan.

Electrolytics tend to get leaky over time if stored with no voltage
across them. When voltage is applied after a long time in storage, an
unusually high leakage current will flow until the insulating film
reforms. If they have been stored long enuogh, this re-forming process
can draw a lot of current and make the capacitor get hot and go bang.
For this reason it is best to do it with a current-limiting resistor. If
you are intending to store electrolytic capacitors for a long time, it
might be worthwhile making provision to charge them periodically to
prevent them from becoming leaky. Similarly, it is worth powering up
stored equipment on a regular basis to re-form the capacitors in the
equipment so that it doesn't go bang when powered on after a long period
of being off.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Monday, August 28, 2023 at 10:15:50 AM UTC-7, ohg...@gmail.com wrote:

On Monday, August 28, 2023 at 7:29:09 AM UTC-4, Dan Green wrote:

Hi all,

Is this okay? I'm talking about replacing electros that have been in service for like 30+ years and which have a rep for failing by then
(Frako caps) with old but unused electrolytics; so called "new old
stock" caps of reputable manufacturers of the same spec. I can't see
an issue with this but am no expert so.... what d'yall think?

Dan.

Years ago, I tossed out my NOS electros because testing them was uncovering some leakage at voltage. I don't recall the brand names if you're wondering that but brand new quality caps are so cheap that it didn't make sense for me to use the old ones.

It's a transient leakage, probably. The manufacturer poles the electrolytics by deliberately feeding leakage
current, to drive the chemistry to form the oxide layer, which... doesn't leak.

After storage for months to years, the oxide layer can thin or perforate, but biasing it up (and leaving it
at voltage for a few minutes to hours) rebuilds the oxide. NOS items don't meet like-new specs
straight off the shelf, but usually DO work normally, by day two under bias. I've also used a
curve tracer to watch the leakage, and applied hot air to speed it up, and re-formed electrolytics
back to good-as-new while watching the leakage current dwindle.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Note, for the record: When I purchase new caps, they still get tested for ESR and value prior to installation. All of them.

Now, here I am with a choice: $20 for a high-value, high voltage electrolytic cap. Or, $0 for a NOS one that, although never installed or used, has been sitting in my closet, or $8 for one that has been sitting on some dealer's shelf (properly
conditioned, of course) for the last 20 years. I do all that has been suggested in this thread to bring that NOS cap up to proper behavior. Or so I think.

That cap goes *POOF*, and takes some unobtanium parts with it.

What have I saved?

Peter Wieck
Melrose Park, PA

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Fri, 1 Sep 2023 11:16:10 -0700 (PDT), "Peter W."
<peterwieck33@gmail.com> wrote:

Note, for the record: When I purchase new caps, they still get tested for ESR and value prior to installation. All of them.

Now, here I am with a choice: $20 for a high-value, high voltage electrolytic cap. Or, $0 for a NOS one that, although never installed or used, has been sitting in my closet, or $8 for one that has been sitting on some dealer's shelf (properly

conditioned, of course) for the last 20 years. I do all that has been suggested in this thread to bring that NOS cap up to proper behavior. Or so I think.

That cap goes *POOF*, and takes some unobtanium parts with it.

What have I saved?

Sorry, it seems you've been out-voted. Re-formed & tested NOS wins.
:-)

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Saturday, September 2, 2023 at 10:52:31 AM UTC-4, Dan Green wrote:

On Fri, 1 Sep 2023 11:16:10 -0700 (PDT), "Peter W."
<peterw...@gmail.com> wrote:

Note, for the record: When I purchase new caps, they still get tested for ESR and value prior to installation. All of them.

Now, here I am with a choice: $20 for a high-value, high voltage electrolytic cap. Or, $0 for a NOS one that, although never installed or used, has been sitting in my closet, or $8 for one that has been sitting on some dealer's shelf (properly

conditioned, of course) for the last 20 years. I do all that has been suggested in this thread to bring that NOS cap up to proper behavior. Or so I think.

That cap goes *POOF*, and takes some unobtanium parts with it.

What have I saved?

Sorry, it seems you've been out-voted. Re-formed & tested NOS wins.
:-)

Majority voting is mob rule - doesn't make it the right decision. Even so, I think if you did an actual poll, you'd find going with new production would win.

These aren't $50 parts here. Even quality capacitors are cheap. It makes little sense to reform a cranky electrolytic.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Friday, September 1, 2023 at 11:16:16 AM UTC-7, Peter W. wrote:

Note, for the record: When I purchase new caps, they still get tested for ESR and value prior to installation. All of them.

Now, here I am with a choice: $20 for a high-value, high voltage electrolytic cap. Or, $0 for a NOS one that, although never installed or used, has been sitting in my closet, or $8 for one that has been sitting on some dealer's shelf (properly

conditioned, of course) for the last 20 years. I do all that has been suggested in this thread to bring that NOS cap up to proper behavior. Or so I think.

That cap goes *POOF*, and takes some unobtanium parts with it.

What have I saved?

Why would an old stock capacitor fail? If it was battered, or stored next to the fuming
nitric acid, or poor quality to begin with, maybe. But, if it's just normal aging of
non-biased electrolyte, it's NOT gonna fail, just will take an initial hour or three under
bias to reform the oxide.

You've saved, in 98% of the probable cases, the time it takes to look up mechanically
and electrically suitable replacements, and the overhead costs of shipping and receiving it.

The unobtanium parts are fictitious, I won't address nonissues.

If this were about a production run of 2000 units, with a deadline, and you couldn't take time
to evaluate the whole batch, it'd be a different decision.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

T24gMjAyMy8wOS8wMiAxMTo1MSBwLm0uLCB3aGl0M3JkIHdyb3RlOg0KPiBPbiBGcmlkYXks IFNlcHRlbWJlciAxLCAyMDIzIGF0IDExOjE2OjE24oCvQU0gVVRDLTcsIFBldGVyIFcuIHdy b3RlOg0KPj4gTm90ZSwgZm9yIHRoZSByZWNvcmQ6IFdoZW4gSSBwdXJjaGFzZSBuZXcgY2Fw cywgdGhleSBzdGlsbCBnZXQgdGVzdGVkIGZvciBFU1IgYW5kIHZhbHVlIHByaW9yIHRvIGlu c3RhbGxhdGlvbi4gQWxsIG9mIHRoZW0uDQo+Pg0KPj4gTm93LCBoZXJlIEkgYW0gd2l0aCBh IGNob2ljZTogJDIwIGZvciBhIGhpZ2gtdmFsdWUsIGhpZ2ggdm9sdGFnZSBlbGVjdHJvbHl0 aWMgY2FwLiBPciwgJDAgZm9yIGEgTk9TIG9uZSB0aGF0LCBhbHRob3VnaCBuZXZlciBpbnN0 YWxsZWQgb3IgdXNlZCwgaGFzIGJlZW4gc2l0dGluZyBpbiBteSBjbG9zZXQsIG9yICQ4IGZv ciBvbmUgdGhhdCBoYXMgYmVlbiBzaXR0aW5nIG9uIHNvbWUgZGVhbGVyJ3Mgc2hlbGYgKHBy b3Blcmx5IGNvbmRpdGlvbmVkLCBvZiBjb3Vyc2UpIGZvciB0aGUgbGFzdCAyMCB5ZWFycy4g SSBkbyBhbGwgdGhhdCBoYXMgYmVlbiBzdWdnZXN0ZWQgaW4gdGhpcyB0aHJlYWQgdG8gYnJp bmcgdGhhdCBOT1MgY2FwIHVwIHRvIHByb3BlciBiZWhhdmlvci4gT3Igc28gSSB0aGluay4N Cj4+DQo+PiBUaGF0IGNhcCBnb2VzICpQT09GKiwgYW5kIHRha2VzIHNvbWUgdW5vYnRhbml1 bSBwYXJ0cyB3aXRoIGl0Lg0KPj4NCj4+IFdoYXQgaGF2ZSBJIHNhdmVkPw0KPiANCj4gV2h5 IHdvdWxkIGFuIG9sZCBzdG9jayBjYXBhY2l0b3IgZmFpbD8gICBJZiBpdCB3YXMgYmF0dGVy ZWQsIG9yIHN0b3JlZCBuZXh0IHRvIHRoZSBmdW1pbmcNCj4gbml0cmljIGFjaWQsIG9yIHBv b3IgcXVhbGl0eSB0byBiZWdpbiB3aXRoLCBtYXliZS4gICBCdXQsIGlmIGl0J3MganVzdCBu b3JtYWwgYWdpbmcgb2YNCj4gbm9uLWJpYXNlZCBlbGVjdHJvbHl0ZSwgaXQncyBOT1QgZ29u bmEgZmFpbCwganVzdCB3aWxsIHRha2UgYW4gaW5pdGlhbCBob3VyIG9yIHRocmVlIHVuZGVy DQo+IGJpYXMgdG8gcmVmb3JtIHRoZSBveGlkZS4NCj4gDQo+IFlvdSd2ZSBzYXZlZCwgaW4g OTglIG9mIHRoZSBwcm9iYWJsZSBjYXNlcywgdGhlIHRpbWUgaXQgdGFrZXMgdG8gbG9vayB1 cCBtZWNoYW5pY2FsbHkNCj4gYW5kIGVsZWN0cmljYWxseSBzdWl0YWJsZSByZXBsYWNlbWVu dHMsIGFuZCB0aGUgb3ZlcmhlYWQgY29zdHMgb2Ygc2hpcHBpbmcgYW5kIHJlY2VpdmluZyBp dC4NCj4gDQo+IFRoZSB1bm9idGFuaXVtIHBhcnRzIGFyZSBmaWN0aXRpb3VzLCBJIHdvbid0 IGFkZHJlc3Mgbm9uaXNzdWVzLg0KPiANCj4gSWYgdGhpcyB3ZXJlIGFib3V0IGEgcHJvZHVj dGlvbiBydW4gb2YgMjAwMCB1bml0cywgd2l0aCBhIGRlYWRsaW5lLCBhbmQgeW91IGNvdWxk bid0IHRha2UgdGltZQ0KPiB0byBldmFsdWF0ZSB0aGUgd2hvbGUgYmF0Y2gsIGl0J2QgYmUg YSBkaWZmZXJlbnQgZGVjaXNpb24uDQoNCkVsZWN0cm9seXRpYyBjYXBhY2l0b3JzIGRlcGVu ZCBvbiB0aGUgc2VhbCBmb3IgdGhlaXIgbGlmZS4NCg0KU2VhbHMgYXJlbid0IHBlcmZlY3Qg YW5kIGV2ZW50dWFsbHkgdGhlIGVsZWN0cm9seXRlIGRyaWVzIG91dC4gVGhlbiB0aGUgDQpj YXBhY2l0b3IgZmFpbHMgcGVybWFuZW50bHksIHJlZm9ybWluZyBpc24ndCBwb3NzaWJsZS4N Cg0KTWFudWZhY3R1cmVycyByZWNvbW1lbmQgYSBzaGVsZiBsaWZlIG9mIGFyb3VuZCB0ZW4g eWVhcnMuDQoNClRoZXNlIGRheXMsIGR1ZSB0byB3aGF0IEknbSBzZWVpbmcgaW4gdmludGFn ZSBlcXVpcG1lbnQsIGNhcGFjaXRvcnMgZnJvbSANCnRoZSAxOTgwcyBhbmQgZWFybGllciBz aW1wbHkgY2FuJ3QgYmUgdHJ1c3RlZC4NCg0KQ2FwcyBmcm9tIHRoZSA5MHMgYW5kIDAwJ3Mg YXJlIHN1c3BlY3RzLCBidXQgbm90IHlldCB0aW1lIGZvciBibGFua2V0IA0KcmVwbGFjZW1l bnQuIEV4Y2VwdCBpbiBtb25pdG9ycyBhbmQgc3dpdGNoaW5nIHBvd2VyIHN1cHBsaWVzLi4u dG9vIHdhcm0gDQphbiBlbnZpcm9ubWVudCBmb3IgdGhlIHNlYWxzIHRvIGxhc3QuDQoNCkpv aG4gOi0jKSMNCg0KLS0gDQooUGxlYXNlIHBvc3QgZm9sbG93dXBzIG9yIHRlY2ggaW5xdWly aWVzIHRvIHRoZSBVU0VORVQgbmV3c2dyb3VwKQ0KICAgICAgICAgICAgICAgICAgICAgIEpv aG4ncyBKdWtlcyBMdGQuDQogICAgICAgICM3IC0gMzk3OSBNYXJpbmUgV2F5LCBCdXJuYWJ5 LCBCQywgQ2FuYWRhIFY1SiA1RTMNCiAgICAgICAgICAoNjA0KTg3Mi01NzU3IChQaW5iYWxs cywgSnVrZXMsIFZpZGVvIEdhbWVzKQ0KICAgICAgICAgICAgICAgICAgICAgIHd3dy5mbGlw cGVycy5jb20NCiAgICAgICAgIk9sZCBwaW5iYWxsZXJzIG5ldmVyIGRpZSwgdGhleSBqdXN0 IGZsaXAgb3V0LiINCg0K

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)