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General Discussion / Re: Solartron 7150 Issue
« Last post by Mr Eastwood on October 20, 2018, 02:25:36 PM »
or in old houses with rewireable fuses or fuse links, the only protection is the 100A fuse in the street supply and the cable impedance.

Yep, that would pretty much describe my setup if the plug wasn't a fused one.


I have both the 7150's feed from a socket strip which supposedly has surge protection via plugs with 3 amp fuses, I labeled the plugs;  this is temporary until i get some smaller fuses and some replacement filters;  I'll also look to get them both re-cal'd at some point.

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General Discussion / Re: Solartron 7150 Issue
« Last post by SeanB on October 20, 2018, 01:55:38 PM »
That of course is is you live in the UK with fused plugs, but the rest of the planet pretty much does not have them any more. Good idea, just that so often the fuse is replaced with a bit of tin foil as "temporary" permanent replacement, leaving the only protection being the 32A breaker in the consumer unit, or in old houses with rewireable fuses or fuse links, the only protection is the 100A fuse in the street supply and the cable impedance.
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General Discussion / Re: Solartron 7150 Issue
« Last post by Mr Eastwood on October 19, 2018, 06:01:41 PM »
I didn't get any reply from Schaffner,  I did find a filter on Mouser UK for 26.31. 

so any fuse rating does not make a difference.
But wouldn't a power lead fitted with a 13A fuse make a bigger mess of the Schaffner filter if it failed short than one fitted with a 2 amp fuse?
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General Discussion / Re: Solartron 7150 Issue
« Last post by SeanB on October 14, 2018, 10:31:48 AM »
With the filters some of them have the capacitors before the fuse, so any fuse rating does not make a difference. Best is to just replace the things if they date from before 2000 with a new one, or do a bit of surgery on them to remove the RIFA flame makers.
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General Discussion / Solartron 7150 Issue
« Last post by Mr Eastwood on October 14, 2018, 10:09:46 AM »
Hi,   I already have a working one of these meters which I use all the time but I saw another one on eBay which was sold as spares fairly cheap (35) which arrived the other day;  so I thought I would try and repair it.

When you power it on there are no indicated fault codes,  but the issue is whatever mode of measurement the meter is in the display will flash  "- OL -" or overload. (see pic below)






I checked the main voltage rails and they seemed ok;  I probed over the relays and I could see the switching signals coming in and out of the buffer chip from the controller logic;  one of the relays wouldn't trigger when i clicked through the modes but perhaps it was part of the null feature, or something else.

Well, after a shocking afternoon literally with this unit (lol don't ask!)   I thought I managed to narrow it down;  so I just reheated a load of pins around the suspect area and it started working!   The calibration looks not too bad at all;  the sticker on it says the last calibration was 2016 so that was good.



Well, the story didn't end there! it looked like I was somewhat premature in my celebrations!!, later that day it started glitching out again with the same issue!   I initially started to think it might be a component acting intermittently - that would have been a real nightmare to find and fix;  but what I found was after tapping the board in various places I found that it would fix itself, then fault again.

So, I carefully tapped each component and narrowed the issue down to near the front edge of the board;  after flexing the PCB very slightly one way I could make it work and by flexing it the other way it would fail;   so,  I started looking for any broken tracks on the board;  the PCB looked ok ( i need a pcb inspecting tool i think!), so then I started tapping each component,  then, all of a sudden I noticed the leg on a resistor had separated from the body - so I removed it out and replaced it;  I tested a few resistors of the same value from a batch to get a closer match to the original one,  but the broken resistor was certainly the root cause of the overload issue.







Quick test



Some useful bits are if your TIL117 chip is labeled IC307 then you have a later model 7150 (serial 300921 onwards), and if it's labeled IC306 then you have the older version;  there are some very subtle differences in the power rail circuit if you check the circuit diagram.  I'll have to check my other meter to see if it's a later one.

I left the meter running most the evening and it was fine so I will leave it on for a few days to give it a bit of a soak test;  I know there is a lot of talk about these meters blowing up etc if the filters fail;  I did come across someone who suggested that PAT testing doesn't do these filters any good;  I have emailed Shaffner directly to ask them about possible issues and PAT testers on legacy electronics equipment with regards to the FN 370 type,  not sure if I will get a reply.  But I wondered of the ones that failed very badly, what size/ type of fuse did they use in the mains power lead feeding the meter;  most people? use these common power leads interchangeably between different devices - could they have minimized the damage and fire risk by using a smaller more suitable fuse and labeling it for the solartron maybe?


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Tutorials, lessons and courses / Re: Setting up a solar power generator.
« Last post by hanoisss on September 24, 2018, 01:24:03 AM »

I agree with this opinion.
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YouTube Video Episodes / Re: High Frequency High Voltage Circuit
« Last post by hanoisss on September 24, 2018, 01:23:05 AM »
I think the answer is very relevant.
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General Discussion / Two wires coming together via electromagnetic attraction
« Last post by DanD.1 on September 22, 2018, 04:22:18 PM »
Hello, I have a very limited amount of knowledge regarding basic electromagnets. I was thinking of bringing two tips of wires together using an electromagnetic attraction between them (I attached a picture of what I am talking about). I was wondering if this is possible? I would appreciate some feedback regarding this.
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Tutorials, lessons and courses / Re: Setting up a solar power generator.
« Last post by Yamaguchi on September 19, 2018, 03:55:04 AM »
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