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Discussion of precise voltage measurement

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Guildline 9578 / Solartron 7081 Schaffner Replacement

TM
Todd Micallef
Sun, Aug 17, 2014 1:28 AM

I recently purchased a defective 9578 and have been able to get it working
(so far). Everything appears to be responding now through the front panel
and the serial port. I wanted to let the meter run for several days to
settle in but with the recent postings of Schaffner input filters failing
shorted, I went ahead and ordered new replacements for this unit and my
other 7061.

The new model is the FN372-2-22 and all pinouts appear to match based on
manufacturers datasheets. The only snag that I have run into is a 1Meg
resistor soldered across the output of the filter. I looked in the service
manual and there is no mention of this part. I know others here have
replaced the Schaffner filters and I would like to know if there is any
benefit to adding this resistor?

Once I get this burned in I will want to go through the calibration
procedure as soon as I order some Fischer connectors. I just need to know
if I need two of the S104A053 connectors for shorting the front and rear ,
or can I get away with just one?

I have a complete set of cables that came with my 7061, but I will have to
make a separate cable for the ratio reference input.

Also, I would like to thank Dave Partridge and Mickle T for their detailed
repairs that were helpful in diagnosing the several problems I found with
this meter.

Todd

I recently purchased a defective 9578 and have been able to get it working (so far). Everything appears to be responding now through the front panel and the serial port. I wanted to let the meter run for several days to settle in but with the recent postings of Schaffner input filters failing shorted, I went ahead and ordered new replacements for this unit and my other 7061. The new model is the FN372-2-22 and all pinouts appear to match based on manufacturers datasheets. The only snag that I have run into is a 1Meg resistor soldered across the output of the filter. I looked in the service manual and there is no mention of this part. I know others here have replaced the Schaffner filters and I would like to know if there is any benefit to adding this resistor? Once I get this burned in I will want to go through the calibration procedure as soon as I order some Fischer connectors. I just need to know if I need two of the S104A053 connectors for shorting the front and rear , or can I get away with just one? I have a complete set of cables that came with my 7061, but I will have to make a separate cable for the ratio reference input. Also, I would like to thank Dave Partridge and Mickle T for their detailed repairs that were helpful in diagnosing the several problems I found with this meter. Todd
TM
Todd Micallef
Sun, Aug 17, 2014 3:38 AM

Never mind, I looked in the 7061 service manual and found the resistor. Is
there a recommended type of resistor for use across mains? I am thinking
the carbon comp resistor should be replaced with a metal glazed film type
or anything listed as flame proof.

Todd

On Sat, Aug 16, 2014 at 9:28 PM, Todd Micallef tmicallef@gmail.com wrote:

The new model is the FN372-2-22 and all pinouts appear to match based on
manufacturers datasheets. The only snag that I have run into is a 1Meg
resistor soldered across the output of the filter. I looked in the service
manual and there is no mention of this part. I know others here have
replaced the Schaffner filters and I would like to know if there is any
benefit to adding this resistor?

Todd

Never mind, I looked in the 7061 service manual and found the resistor. Is there a recommended type of resistor for use across mains? I am thinking the carbon comp resistor should be replaced with a metal glazed film type or anything listed as flame proof. Todd On Sat, Aug 16, 2014 at 9:28 PM, Todd Micallef <tmicallef@gmail.com> wrote: > > The new model is the FN372-2-22 and all pinouts appear to match based on > manufacturers datasheets. The only snag that I have run into is a 1Meg > resistor soldered across the output of the filter. I looked in the service > manual and there is no mention of this part. I know others here have > replaced the Schaffner filters and I would like to know if there is any > benefit to adding this resistor? > > > > Todd >
DC
David C. Partridge
Sun, Aug 17, 2014 7:25 AM

When you install the new filter, you may find you also need to move the
voltage selector cam from the old filter to the new one, as the new units
seem to have different cams and voltage values thereon.

Regards,
David Partridge
-----Original Message-----
From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On
Behalf Of Todd Micallef
Sent: 17 August 2014 04:38
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Guildline 9578 / Solartron 7081
SchaffnerReplacement

Never mind, I looked in the 7061 service manual and found the resistor. Is
there a recommended type of resistor for use across mains? I am thinking the
carbon comp resistor should be replaced with a metal glazed film type or
anything listed as flame proof.

Todd

When you install the new filter, you may find you also need to move the voltage selector cam from the old filter to the new one, as the new units seem to have different cams and voltage values thereon. Regards, David Partridge -----Original Message----- From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On Behalf Of Todd Micallef Sent: 17 August 2014 04:38 To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] Guildline 9578 / Solartron 7081 SchaffnerReplacement Never mind, I looked in the 7061 service manual and found the resistor. Is there a recommended type of resistor for use across mains? I am thinking the carbon comp resistor should be replaced with a metal glazed film type or anything listed as flame proof. Todd
DC
David C. Partridge
Sun, Aug 17, 2014 7:30 AM

Only one shorting plug is needed.

Regards,
David Partridge
-----Original Message-----
From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On
Behalf Of Todd Micallef
Sent: 17 August 2014 02:29
To: Discussion of precise voltage measurement
Subject: [volt-nuts] Guildline 9578 / Solartron 7081 Schaffner Replacement

I just need to know if I need two of the S104A053 connectors for shorting

the front and rear , or can I get away with just one?

Only one shorting plug is needed. Regards, David Partridge -----Original Message----- From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On Behalf Of Todd Micallef Sent: 17 August 2014 02:29 To: Discussion of precise voltage measurement Subject: [volt-nuts] Guildline 9578 / Solartron 7081 Schaffner Replacement >I just need to know if I need two of the S104A053 connectors for shorting the front and rear , or can I get away with just one?
TM
Todd Micallef
Sun, Aug 17, 2014 6:30 PM

Dave,

Thanks for the heads up. I went ahead and verified that all pins matched
the schematic by changing the cam to the four settings and all are as
expected. The new cams have "230vac" printed on them and the old one has
"220 vac".
I went ahead and installed the old one to prevent any future issues should
this meter end up outside the US someday.

I will plan on getting a connector this week. The front panel input is also
damaged. Kensington Electronics has all the parts in stock.

Todd

When you install the new filter, you may find you also need to move the

voltage selector cam from the old filter to the new one, as the new units
seem to have different cams and voltage values thereon.

Regards,
David Partridge

Dave, Thanks for the heads up. I went ahead and verified that all pins matched the schematic by changing the cam to the four settings and all are as expected. The new cams have "230vac" printed on them and the old one has "220 vac". I went ahead and installed the old one to prevent any future issues should this meter end up outside the US someday. I will plan on getting a connector this week. The front panel input is also damaged. Kensington Electronics has all the parts in stock. Todd When you install the new filter, you may find you also need to move the > voltage selector cam from the old filter to the new one, as the new units > seem to have different cams and voltage values thereon. > > Regards, > David Partridge > >