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Resistor networks, polarized?

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Gil G.

Resistor networks, polarized?

Hello,

I am building the KSB2 tonight, and I put a resistor network the wrong way..
Aren't these just resistors? Why would there be a pin 1? Should I remove it?
If so, how do I do that? I have solder wick, tried, but it isn't budging…

Thanks,

Gil.
--
PGP Key: http://keskydee.com/gil.asc

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Dick Dievendorff

Re: Resistor networks, polarized?

A resistor network normally has one common pin; one side of each of the
resistors goes to a distinguished pin. It isn't going to work if it's in
backward.

I invested in a Hakko 808 to remove solder from multi-pin devices. I find it
difficult with just solder wick.

It may be less difficult overall to just cut the part out, remove the pins
one by one, and order a replacement resistor. They aren't all that
expensive. A lot of time with heat and solder wick can be tough on the PC
board.

Good luck!

Dick, K6KR

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Gil G.
Sent: Thursday, October 18, 2012 4:36 PM
To: [hidden email]
Subject: [Elecraft] Resistor networks, polarized?

Hello,

I am building the KSB2 tonight, and I put a resistor network the wrong way..
Aren't these just resistors? Why would there be a pin 1? Should I remove it?
If so, how do I do that? I have solder wick, tried, but it isn't budging.

Thanks,

Gil.
--
PGP Key: http://keskydee.com/gil.asc

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Vic Rosenthal

Re: Resistor networks, polarized?

In reply to this post by Gil G.

If you reversed RP1, 2 or 3 then you are OK. But RP5 has one side of all the resistors
connected together and to pin 1! Look at the schematic and you'll see this. There doesn't
seem to be a RP4.

One way to remove it is to cut all the pins with flush cutters and then take them out one
at a time. You will need a new part, but it's better than damaging the board!

On 10/18/2012 4:35 PM, Gil G. wrote:

> Hello,
>
> I am building the KSB2 tonight, and I put a resistor network the wrong way..
> Aren't these just resistors? Why would there be a pin 1? Should I remove it?
> If so, how do I do that? I have solder wick, tried, but it isn't budging…
>
> Thanks,
>
> Gil.
> --
> PGP Key: http://keskydee.com/gil.asc
>

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/

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Mike Morrow-3

Re: Resistor networks, polarized?

In reply to this post by Gil G.

> A resistor network normally has one common pin; one side of each of the
> resistors goes to a distinguished pin. It isn't going to work if it's in
> backward.

In the KSB2, this is only true for RP5. RP1, RP2, and RP3 (there is no RP4)
have two pins per identically valued resistor. It won't matter what orientation
was used when the RP is soldered in.

So...what RP was installed backward?

> It may be less difficult overall to just cut the part out, remove the pins
> one by one, and order a replacement resistor.

That would be the best advice it one are unfortunate enough to have installed
RP5 in backward. But if RP1, RP2, or RP3 has been soldered in backward, just
let it be.

73,
Mike / KK5F
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Gil G.

Re: Resistor networks, polarized?

Hello Mike,

And thank you everyone for all the answers.

It is RP2… It does have a dot though, and a round pad on the PCB for pin 1.

So, I can leave it as is?

Gil.
--
PGP Key: http://keskydee.com/gil.asc

On Oct 18, 2012, at 8:23 PM, Mike Morrow wrote:

>
>> A resistor network normally has one common pin; one side of each of the
>> resistors goes to a distinguished pin. It isn't going to work if it's in
>> backward.
>
> In the KSB2, this is only true for RP5. RP1, RP2, and RP3 (there is no RP4)
> have two pins per identically valued resistor. It won't matter what orientation
> was used when the RP is soldered in.
>
> So...what RP was installed backward?

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Don Wilhelm-4

Re: Resistor networks, polarized?

Gil,

I can confirm that RP2 is not orientation sensitive, but RP5 must be
oriented properly if the speech compressor is to operate properly.

73,
Don W3FPR

On 10/18/2012 9:03 PM, Gil G. wrote:

> Hello Mike,
>
> And thank you everyone for all the answers.
>
> It is RP2… It does have a dot though, and a round pad on the PCB for pin 1.
>
> So, I can leave it as is?
>
> Gil.
>

Gil G.

Re: Resistor networks, polarized?

Great! Saves me a lot of grief! Thanks everyone!

Gil.
--
PGP Key: http://keskydee.com/gil.asc

On Oct 18, 2012, at 9:23 PM, Don Wilhelm wrote:

> Gil,
>
> I can confirm that RP2 is not orientation sensitive, but RP5 must be oriented properly if the speech compressor is to operate properly.
>
> 73,
> Don W3FPR
>
> On 10/18/2012 9:03 PM, Gil G. wrote:
>> Hello Mike,
>>
>> And thank you everyone for all the answers.
>>
>> It is RP2… It does have a dot though, and a round pad on the PCB for pin 1.
>>
>> So, I can leave it as is?
>>
>> Gil.
>>
>

Bob-270

Re: Resistor networks, polarized?

In reply to this post by Vic Rosenthal

I also believe it is better to remove it and the extract the pins one at a
time. A method that I've used many times is to slowly and gently rock the part
back and forth. First you will only get very little movement but with metal
fatigue it increases. Eventually with care it breaks off cleanly and the pins
are easy to extract. Two hazards associated with cutting them. They shatter and
are an eye hazard but you should be wearing eye protection even clipping wires
etc. Second there is more board risk with the cutters. It is pretty easy to
nick or cut a land on the top of the PCB with the cutter tips.

Boils down to what you are comfortable with. The average ham will not have the
Pro rework station equipment where there is a tip to heat all the leads and
extract the component intact. No matter what method you use "care" is the
operative word.

73,
Bob
K2TK

On 10/18/2012 8:15 PM, Vic K2VCO wrote:

> If you reversed RP1, 2 or 3 then you are OK. But RP5 has one side of all the resistors
> connected together and to pin 1! Look at the schematic and you'll see this. There doesn't
> seem to be a RP4.
>
> One way to remove it is to cut all the pins with flush cutters and then take them out one
> at a time. You will need a new part, but it's better than damaging the board!
>
> On 10/18/2012 4:35 PM, Gil G. wrote:
>> Hello,
>>
>> I am building the KSB2 tonight, and I put a resistor network the wrong way..
>> Aren't these just resistors? Why would there be a pin 1? Should I remove it?
>> If so, how do I do that? I have solder wick, tried, but it isn't budging…
>>
>> Thanks,
>>
>> Gil.
>> --
>> PGP Key: http://keskydee.com/gil.asc
>>

LA8OKA

Vedr: Resistor networks, polarized?

In reply to this post by Gil G.

You can remove the resistor pack by using heated solder on all the pins on one side. (You need to be fast!)
Heat up one side with the soldering iron and apply lot of solder, the solder works as a heat distributor, losen one side, and do the same on the other side, use solder wick after to remove all the solder from the PCB and the resistor pack.

Martin Storli
LA8OKA
Oslo, Norway

ARCTICPEAK's Radio pages!
http://www.arcticpeak.com/radio.htm

________________________________
Fra: Gil G. <[hidden email]>
Til: [hidden email]
Sendt: Fredag, 19. oktober 2012 1.35
Emne: [Elecraft] Resistor networks, polarized?

Hello,

I am building the KSB2 tonight, and I put a resistor network the wrong way..
Aren't these just resistors? Why would there be a pin 1? Should I remove it?
If so, how do I do that? I have solder wick, tried, but it isn't budging…

Thanks,

Gil.
--
PGP Key: http://keskydee.com/gil.asc

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