EDAboard.com | EDAboard.de | EDAboard.co.uk | WTWH Media

This has me puzzled (resistor change)

Ask a question - edaboard.com

elektroda.net NewsGroups Forum Index - Repair Electronics - This has me puzzled (resistor change)

Goto page Previous  1, 2

Jon Elson
Guest

Mon Jan 21, 2019 9:45 pm   



tubeguy_at_myshop.com wrote:


Quote:

I was always under the impression that film resistors are identical
(electrically), and their only difference is appearance. Now I learn
that is not true.....

Very high value film resistors are made with some composition sprayed on a
ceramic tube, and then an abrasive jet cuts a spiral groove in the film
element. That can add inductance, and the higher the resistance value they
are aiming for, the more inductance. In tube circuits, it is not unusual to
have megohm resistors, so I can see how this could be a problem.

Jon

Phil Allison
Guest

Mon Jan 21, 2019 9:45 pm   



Jon Elson wrote:

Quote:


Very high value film resistors are made with some composition sprayed on a
ceramic tube, and then an abrasive jet cuts a spiral groove in the film
element.


** In fact, film resistors of all values are made that way.


Quote:
That can add inductance, and the higher the resistance value they
are aiming for, the more inductance.


** Absolute CRAP !!!!

Where does this shite come from ??

ONLY with *low value* resistors can the TINY inducatance created by spiralling become significant and then only at RF frequencies.


Quote:
In tube circuits, it is not unusual to
have megohm resistors, so I can see how this could be a problem.


** Huh ????

Jumps straight from the rediculous to the absurd.

Go away fool.


..... Phil


Guest

Mon Jan 21, 2019 10:45 pm   



On Monday, January 21, 2019 at 4:14:29 PM UTC-5, Mike Coon wrote:
Quote:
In article <MPG.36afad472e863d9d98994a_at_news.east.earthlink.net>,
rmowery28146_at_earthlink.net says...

Could it have been possiable that the new resistor was bad, or maybe the
color code was read wrong so the wrong value was put in ?

As a lad, scratching through my dad's old box of mixed resistors,
looking for a near-enough value to one I needed, I used to get a strong
urge to choose any old value and re-paint the colours...

Mike.


I find it amazing how I can spot a certain color code in a box of mixed up resistors.

I'm looking for yellow purple red.

Ah there's one.

m

Ralph Mowery
Guest

Mon Jan 21, 2019 10:45 pm   



In article <6ea7b3ba-ea28-4479-912d-751f3c703e2b_at_googlegroups.com>,
ohger1s_at_gmail.com says...
Quote:

Prob not "bad", but maybe just way off value (or read incorrectly as you surmised). I've been given tons of old parts including resistor assortments. You can't believe how often the wrong resistor (usually multiplier) was in the wrong drawer.

When sorting new old stock carbon carbon comp resistors, I don't sort them by printed value, but actual measured resistance since so many of them are closer to the next value up or down than they are to their own printed value. I only keep them to put in old tube radios for authenticity's sake.



I have not done much repairing electronics in a while and had a bunch of
1/2 watt carbon resistors that I had been using.

Found out when I ordered an assortment of modern reisitors that they had
an extra band where there were 3 digits and the multiplier instead of
the 2 digits and multiplier that I was use to.

I am well aware that the older carbon resistors often go up in value as
they age even if new. I always measure the resistors before I use them.
I do the same with the electrolytic capacitors.

Mike Coon
Guest

Mon Jan 21, 2019 10:45 pm   



In article <MPG.36afad472e863d9d98994a_at_news.east.earthlink.net>,
rmowery28146_at_earthlink.net says...
Quote:

Could it have been possiable that the new resistor was bad, or maybe the
color code was read wrong so the wrong value was put in ?


As a lad, scratching through my dad's old box of mixed resistors,
looking for a near-enough value to one I needed, I used to get a strong
urge to choose any old value and re-paint the colours...

Mike.

Phil Allison
Guest

Mon Jan 21, 2019 11:45 pm   



Ralph Mowery wrote:


Quote:




I am well aware that the older carbon resistors often go up in value as
they age even if new. I always measure the resistors before I use them.
I do the same with the electrolytic capacitors.



** If you find an electro well above its marked capacitance value - what do you conclude ??



.... Phil

Sjouke Burry
Guest

Mon Jan 21, 2019 11:45 pm   



On 21-1-2019 22:51, Phil Allison wrote:
Quote:

Ralph Mowery wrote:






I am well aware that the older carbon resistors often go up in value as
they age even if new. I always measure the resistors before I use them.
I do the same with the electrolytic capacitors.



** If you find an electro well above its marked capacitance value - what do you conclude ??



... Phil

That the oxide layer has degraded, and might be about to fail?


John-Del
Guest

Tue Jan 22, 2019 12:45 am   



On Monday, January 21, 2019 at 4:39:02 PM UTC-5, mako...@yahoo.com wrote:
Quote:
On Monday, January 21, 2019 at 4:14:29 PM UTC-5, Mike Coon wrote:
In article <MPG.36afad472e863d9d98994a_at_news.east.earthlink.net>,
rmowery28146_at_earthlink.net says...

Could it have been possiable that the new resistor was bad, or maybe the
color code was read wrong so the wrong value was put in ?

As a lad, scratching through my dad's old box of mixed resistors,
looking for a near-enough value to one I needed, I used to get a strong
urge to choose any old value and re-paint the colours...

Mike.

I find it amazing how I can spot a certain color code in a box of mixed up resistors.

I'm looking for yellow purple red.

Ah there's one.

m


Back when I used to carry a big box of tubes (valves) for on site repair, I could spot any tube out of hundreds in seconds. After a long time using them, we don't "read" the tube number as much as just flat out recognize it - just like when reading words.

Phil Allison
Guest

Tue Jan 22, 2019 7:45 am   



Sjouke Burry wrote:



Quote:




** If you find an electro well above its marked capacitance value
- what do you conclude ??



... Phil


That the oxide layer has degraded, and might be about to fail?


** How do you check for this?


...... Phil

Goto page Previous  1, 2

elektroda.net NewsGroups Forum Index - Repair Electronics - This has me puzzled (resistor change)

Ask a question - edaboard.com

Arabic version Bulgarian version Catalan version Czech version Danish version German version Greek version English version Spanish version Finnish version French version Hindi version Croatian version Indonesian version Italian version Hebrew version Japanese version Korean version Lithuanian version Latvian version Dutch version Norwegian version Polish version Portuguese version Romanian version Russian version Slovak version Slovenian version Serbian version Swedish version Tagalog version Ukrainian version Vietnamese version Chinese version Turkish version
EDAboard.com map