[volt-nuts] Solartron 7081 testing

Михаил timka2k at yandex.ru
Thu Dec 1 17:14:42 UTC 2011

Thank you very much for your help!
Testing that I needed is absolutely safe and does not affect the 'fresh'
calibration. The commands list with parenthesis around what you need to enter is:
Step 3:
Step 5:

All of these commands discussed in the Operating Manual. (DRIFT,OFF) allows to
temporarily disable periodic ADC drift correction. (MODE,TEST0) disables input
amplifier and shorts ADC. (DRIFT,NOW) runs single drift correction cycle.
(MODE,TEST10) connects input amplifier to internal reference (+ 10 V).
(MODE,TESTK) connects ADC integrator input to Ohms current source, that is
equivalent to about 1.6 V ADC input value.
All of these commands are part of the standart internal Self Test. 7081 input
does not matter because its automatically disconnects during tests procedure.
7081 must be cold, i.e. no 'warm up' before running the tests.

My Solartron 7081 was very ill: no LED signs, no display, no life at all :(
I'm spent amount of time to research Earthy Logic and Processor boards, I/O and
memory map, disassemble some of the early ROM procedures, emulate 7081 firmware
via 6809 CPU emulator, change RAM/ROM chips decoding structure to replace the
old and rare 2564 and 6117 chips and adopt PCB for new 28F010 and 6264 ones. I'm
recompiling all of the 2564 ROM contents (1984 year) to the linear block and add to it
recompiled ROMs content by Dave Partridge (1986 year) and flash its to the one
28F010 EEPROM. Now the DMM came to life again :) and I'm continue to research
the ADC and analog subsistem.
This is the replaced parts, including old and broken boards interconnection
cable, two semi-defective RAM and ROM chips: http://img710.imageshack.us/img710/3870/oldromram.jpg
This is the new sub-PCB with two banked ROM 28F010 and address decoders:

Mickle T. (sorry for my horrible English)

Thursday, December 1, 2011, 6:38:00 PM, you wrote:
JLT> Mickle,
JLT> I can probably do this if I can find the time.  Perhaps this weekend.  Will
JLT> I be doing anything to upset my 'fresh' calibration?  

JLT> Just to make sure I understand the commands, can you send me the command
JLT> list with parenthesis around what I need to enter, such as (OUTPUT,RS232,ON)
JLT> (DRIFT,OFF), etc.  I don't want to add additional stuff to the command that
JLT> should not be there.  I also note there is a 'TEST0' which I think is a zero
JLT> but since there is a 'TESTK', I just want to make sure.  I have not read the
JLT> manual in detail.  Are these commands discussed in the manual?  Also, do I
JLT> need to 'short' the input or just leave it open?  If I need to 'short' the
JLT> input, do I 'short' just 'Lo' to 'Hi' or do I need to include the 'Ohm
JLT> source' Lo and Hi as well as the 'Guard'?  How long do I need to let the
JLT> meter 'warm up' before running the tests?

JLT> What ROM upgrade did you do?

JLT> Would also love to see the details of your repair.

JLT> Joe

JLT> -----Original Message-----
JLT> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
JLT> Behalf Of Òèìîôååâ Ìèõàèë
JLT> Sent: Thursday, December 01, 2011 5:35 AM
JLT> To: 'Discussion of precise voltage measurement'
JLT> Subject: [volt-nuts] Solartron 7081 testing

JLT> Hi, my friends! Hi, Joe!

JLT> Now, I examine the characteristics of the Solartron 7081 after ROM upgrade,
JLT> PCB repairing and small schematic modifications. I need some help with the
JLT> measurements with a known good device 7081, connected to PC with the RS232
JLT> and terminal program. Measurements does not require any special input or
JLT> input leads at all, only some terminal commands and result logs needed. Step
JLT> 1: Activate terminal program and log all output to the file. Switch on the
JLT> 7081. Step 2: Via 7081 front panel buttons select 7x9 mode and TRACK. Step
JLT> 3: Via terminal program enter the following two commands: OUTPUT,RS232,ON
JLT> DRIFT,OFF MODE,TEST0 After that, TSTV0 appears on the 7081 display with ADC
JLT> zero measurement results. Step 4: Wait approximately 30-60 minutes while the
JLT> statistics are collected and saved to log file. Step 5: Enter the following
JLT> commands via terminal program. After each command need a delay about 20-30
JLT> sec for result sampling!!! DRIFT,NOW MODE,TEST10 DRIFT,NOW MODE,TEST0

JLT> That's all! Now you can stop logging, turn off the 7081 and shut down the
JLT> terminal program.

JLT> Mickle T.

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Ñ óâàæåíèåì,
 ??????                            mailto:timka2k at yandex.ru

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