Confused; Resistor reading help
 

Hi,
The schematic says it an 500,000 ohms.
My digital meter reads it as this: 0.590 M
(M) for megohms.

I went to an resistor website that showed me this:
First Band: Green
Second Band: Black
Third Band: Yellow
Forth Band: None
Resistance: 500,000 ohms or 500.00 kilohoms or 0.50 Mohms
Tolerance: ± 20%
Resistance Range with Error: 400,000 ohms - 600,000 ohms

So, it safe to say the resistor is good & that my meter is reading it as
the above 0.50 Mohms? Cause when I check a 20,000 ohm I get this on the
meter: 20.71K & I understand that, but the 0.590M I'm not certain.

Sorry, need to be sure. Thanks.

Confused; Resistor reading help
 

"_J D_" wrote in message
...
Hi,
The schematic says it an 500,000 ohms.
My digital meter reads it as this: 0.590 M
(M) for megohms.

I went to an resistor website that showed me this:
First Band: Green
Second Band: Black
Third Band: Yellow
Forth Band: None
Resistance: 500,000 ohms or 500.00 kilohoms or 0.50 Mohms
Tolerance: ± 20%
Resistance Range with Error: 400,000 ohms - 600,000 ohms

So, it safe to say the resistor is good & that my meter is reading it as
the above 0.50 Mohms? Cause when I check a 20,000 ohm I get this on the
meter: 20.71K & I understand that, but the 0.590M I'm not certain.

Sorry, need to be sure. Thanks.


You're reading it right. But, it should really be considered out of range,
and replaced with something closer to the original value, even though it is
technically within the 20% tolerance range.

Confused; Resistor reading help
 

"_J D_" wrote in message
...
Hi,
The schematic says it an 500,000 ohms.
My digital meter reads it as this: 0.590 M
(M) for megohms.

I went to an resistor website that showed me this:
First Band: Green
Second Band: Black
Third Band: Yellow
Forth Band: None
Resistance: 500,000 ohms or 500.00 kilohoms or 0.50 Mohms
Tolerance: ± 20%
Resistance Range with Error: 400,000 ohms - 600,000 ohms

So, it safe to say the resistor is good & that my meter is reading it as
the above 0.50 Mohms? Cause when I check a 20,000 ohm I get this on the
meter: 20.71K & I understand that, but the 0.590M I'm not certain.

Sorry, need to be sure. Thanks.

Yes your meter is right and the resistor is showing a impedance of 590,000
ohms or 590k. Your meter just states it as .590M instead of 590k, Same
thing. Are you concerned about the tollerance? Carbon comps can drift a long
ways over time and I imagine the application within the circuit isn't that
critical as long as it's within spec of the resistors limits.

BH

Confused; Resistor reading help
 

In addition to what others said,

This is why I replace all the resistors in a restoration. Once you start to
use that resistor (radio) you have a good chance the resistor and the others
will drift even more when they get hot. Will it be a perminent drift and
cause you heart acke? Perhaps. Why did it not drift to the lower value of
the 20% tolerance? I don't know. But many many old resistors have drifted
higher and not lower. I really can't remember finding a vintage reistor
that has drifted lower.

How much does a 1/2 watt (twice your 1/4 watt) 5% tolerance resistor cost?
About 7 cents. In bulk per 100 about 4 cents. And presumably you have
already cut one lead out of the circuit to measure the resistor.

How much time/cost does it take to cut a lead, ohm the resistor, solder it
back in compaired to two snips and splicing in a known good replacement? It
takes me less time to snip, snip and replace. And MUCH less time than when I
had to reopen a chassis three times to chase down three drifting resistors.

It is your call. For me restorations include resistors as well as
capacitors.

Good luck on the restoration. Keep us posted!

Paul P.

Confused; Resistor reading help
 

In addition to what others said,

This is why I replace all the resistors in a restoration. Once you start to
use that resistor (radio) you have a good chance the resistor and the others
will drift even more when they get hot. Will it be a permanent drift and
cause you heart ache? Perhaps. Why did it not drift to the lower value of
the 20% tolerance? I don't know. But many many old resistors have drifted
higher and not lower. I really can't remember finding a vintage resistor
that has drifted lower.

How much does a 1/2 watt (twice your 1/4 watt) 5% tolerance resistor cost?
About 7 cents. In bulk per 100 about 4 cents. And presumably you have
already cut one lead out of the circuit to measure the resistor.

How much time/cost does it take to cut a lead, ohm the resistor, solder it
back in compared to two snips and splicing in a known good replacement? It
takes me less time to snip, snip and replace. And MUCH less time than when I
had to reopen a chassis three times to chase down three drifting resistors.

It is your call. For me restorations include resistors as well as
capacitors.

Good luck on the restoration. Keep us posted!

Paul P.

Confused; Resistor reading help
 

"_J D_" wrote in message
...
Hi,
The schematic says it an 500,000 ohms.
My digital meter reads it as this: 0.590 M
(M) for megohms.

I went to an resistor website that showed me this:
First Band: Green
Second Band: Black
Third Band: Yellow
Forth Band: None
Resistance: 500,000 ohms or 500.00 kilohoms or 0.50 Mohms
Tolerance: ± 20%
Resistance Range with Error: 400,000 ohms - 600,000 ohms

So, it safe to say the resistor is good & that my meter is reading it as
the above 0.50 Mohms? Cause when I check a 20,000 ohm I get this on the
meter: 20.71K & I understand that, but the 0.590M I'm not certain.

Sorry, need to be sure. Thanks.

One of the things I was taught at my training classes when I joined the RAF
( many years ago !) was that carbon resistors will drift higher as they age.
I just checked several old 500k resistors in my box and found the closest to
be 508.4k, one was 610k. Generally I find that if resistors in a circuit
are within 10% of the specified value then all is well. I figure the most
critical is in oscillator and frequency control circuits, but usually there
are variable trimming capacitors to compensate.

Confused; Resistor reading help
 

Thanks so much for the response & advice.
You ppl are great!

The reason I was questioning them resistors was.. cause I picked up an
Emerson FL414 unrestored and tested the tubes in my test radio & the
50L6 was dead.

Thinking it just as being an cap failure,tho wasn't sure.. I’m still
trying to learn.
Will do a recap & replace the res on it sometime soon.