If you ever need to work on the Ohms circuit of a Solartron 7150 Plus, be warned, there is a schematic error in the service manual.  In diagram 2.1 (PCB1, Floating Analog), the top of resistor R22 should connect to the Source terminals of TR4, TR9 and the top of R26.  This "wire" should NOT connect to the gate of TR4 as it appears to do in the schematic.

I couldn't work out what was going on here for a while, and then the penny dropped!

The schematic in the original 7150 Service manual is correct.

Regards,
David Partridge

An updated version of the manual with schematic corrections has been provided by Nigel Clarke (GandalfG8@aol.com) and has been uploaded to Didier Juge's website <www.ko4bb.com>

Dave
-----Original Message-----
From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On Behalf Of David C. Partridge
Sent: 09 November 2010 10:59
To: volt-nuts@febo.com; TekScopes@yahoogroups.com; TekScopes2@yahoogroups.com; hp_agilent_equipment@yahoogroups.com
Subject: [volt-nuts] Schematic error in Solartron 7150 Plus service manual

If you ever need to work on the Ohms circuit of a Solartron 7150 Plus, be warned, there is a schematic error in the service manual.  In diagram 2.1 (PCB1, Floating Analog), the top of resistor R22 should connect to the Source terminals of TR4, TR9 and the top of R26.  This "wire" should NOT connect to the gate of TR4 as it appears to do in the schematic.

I couldn't work out what was going on here for a while, and then the penny dropped!

The schematic in the original 7150 Service manual is correct.

Regards,
David Partridge

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