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Old 25th Jan 2023, 3:09 pm   #1
Bero
Tetrode
 
Join Date: Oct 2003
Location: Zagreb, Croatia
Posts: 87
Default Racal 9301 bad on 1 and 3mV range

I have had this device for years, it was in bad shape but I managed to get it to work on ranges 3, 1,100,30.
Even in the 10mV range it can be used to some extent.
Ranges 1 and 3 mV cannot be calibrated.
I recently acquired replacement boards for this device, hoping to get something out of replacing them.
But the thing is still the same, I follow the instructions and the potentiometer with which to determine the adjustment level, there is simply no more position in which to achieve the correct alignment.
It is about achieving 1V at point TP8 (0822 board) by adjusting potentiometer R67.
Everything else from the setup procedure can be accomplished up to that point.
Maybe someone experienced this kind of failure while repairing their device?
greeting
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Old 28th Jan 2023, 7:43 pm   #2
6SN7WGTB
Hexode
 
Join Date: Apr 2021
Location: Crawley, West Sussex, UK.
Posts: 442
Default Re: Racal 9301 bad on 1 and 3mV range

Seeing your posts on the Racal Dana forum, is this now resolved?
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Old 1st Feb 2023, 1:37 pm   #3
Bero
Tetrode
 
Join Date: Oct 2003
Location: Zagreb, Croatia
Posts: 87
Default Re: Racal 9301 bad on 1 and 3mV range

Thanks Richard,
The problem is mostly solved.
What I would like to find or make myself is probe isolator tip
racal-dana code: 11-1151

So, if someone by some miracle has this racal-probe attachment,
I would buy it if it was for sale.

Solution two: if someone has this kind of accessories, is there a possibility to open it and take a picture of the inside, or write down data about the capacity of the capacitors inside?
It's probably just capacitors.

I assume that it is only an isolator that serves to isolate the device and prevent the formation of a loop,
which could burn the probe due to the potential difference.
Just like an isolation transformer when working with an oscilloscope.
I don't see any other function of it, but it affects the accuracy of the measurement
and it is written in the manual that this extension is always used when measuring with a probe.
.
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