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EEVBlog 121GW Discussion thread

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J-R:
Dave posted the 2.05 firmware one page back.  Here's a link to it: https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=1213626

I'm sure there are units out there where they are "supposed" to have the shim but don't.  Personally I think the shim is not always needed.  I have two that came with the shim but removed it because I thought the switch felt better without it.  Zero issues so far.  If I need it after the contacts wear, I'll re-install.

EEVblog:

--- Quote from: sirtet on July 22, 2021, 11:21:02 am ---I don't know the full Story with the shim that some revisions needed because of a wrong pcb thickness, so:
Do i have to check if my meter needs the shim, or were no meters sold without that fix?

--- End quote ---

IIRC no meters were sold without the shim. It was limited to the Kickstarter shipped units.

Ecogeek:

--- Quote from: EEVblog on March 24, 2021, 07:40:13 am ---
--- Quote from: Wytnucls on March 22, 2021, 09:15:23 pm ---Stick to good brands, like Littelfuse, Cooper Bussmann or Siba if you can, otherwise examine the datasheet carefully for compliance.
--- End quote ---

Beware of fakes on ebay and other places. Because of the very high potential margins on these, the market is awash with fakes.

--- End quote ---
Yes I ordered a pack of "Bussman" fuses from China, strangely arrived same day as my order from EEVBlog Australian shop, the labels were identical to the blown 11A fuse Busman fuse I removed, but the fuse end caps did not have "Bussman" stamped and the cap crimping was not the same. The cap plating was also slightly dull and difficult to get a good low resistance contact with my meter leads, when I did a low ohms resistance check they all measured higher resistance than the fuses supply by the EEVBlog shop. 
Thanks Dave for the much cheaper quality fuses. :)

AVGresponding:

--- Quote from: Ecogeek on July 27, 2021, 08:09:21 pm ---
--- Quote from: EEVblog on March 24, 2021, 07:40:13 am ---
--- Quote from: Wytnucls on March 22, 2021, 09:15:23 pm ---Stick to good brands, like Littelfuse, Cooper Bussmann or Siba if you can, otherwise examine the datasheet carefully for compliance.
--- End quote ---

Beware of fakes on ebay and other places. Because of the very high potential margins on these, the market is awash with fakes.

--- End quote ---
Yes I ordered a pack of "Bussman" fuses from China, strangely arrived same day as my order from EEVBlog Australian shop, the labels were identical to the blown 11A fuse Busman fuse I removed, but the fuse end caps did not have "Bussman" stamped and the cap crimping was not the same. The cap plating was also slightly dull and difficult to get a good low resistance contact with my meter leads, when I did a low ohms resistance check they all measured higher resistance than the fuses supply by the EEVBlog shop. 
Thanks Dave for the much cheaper quality fuses. :)

--- End quote ---

Did you weigh them to see if they are lighter? (no sand inside) Or smash one open to see if it had any?

Ecogeek:
Further information on Bussman DMM-B-11A and ASTM 11A fuses.
As you can see by the photo the plating is duller, the fuses do appear to be OEM (the labels were identical) but possibly old stock or at least different end cap assembly with no OEM cap branding to the Bussman I removed from my meter.

I did some 4 wire resistance measurements (as opposed to multimeter ohms with test probes) with 1A of current flowing.
Results of resistance measurements of six Bussman fuses from Alibaba in mohms.
Bussman DMM-B-11A; 7.446,6.997,7.636,7.298,7.132, 7.306     Average 7.302mohm
weighed in at about 8 grams (on my kitchen scales)

ASTM HV110;  9.255mohm
weighed in at 9 grams

Little Fuse FLU-11A; 8.265mohm

I also did the 4wire resistance measurements of three mulitmeters 10A shunt including fuses (at meter terminals);
Fluke 87  with ASTM HV110 fuse              25.6mohm   (fuse 36% of total)
Agilent U1233A with ASTM HV110 fuse     22.06 mohm (fuse 42% of total)
EEVBlog 121GW with Little Fuse FLU-11A  32.3mohm   (fuse 25.6% of  total)

Conclusion: The spread of 11A fuse resistances was close to 2mohms with the Bussman DMM-B-11A being the lowest, ASTM HV110 the highest with the Little fuse in the middle. The Bussman fuses do appear to be OEM but of unknown age.

PS When I was doing the multimeter 10A resistance measurements I noticed the fluke was "unstable" i.e. seemed to vary which the other two meters did not.  Long story short; the soldering of the fuse holders was causing the problem, the fuse holders only had the fuse tabs soldered and after close to two decades the solder connections were failing. I removed and resoldered including the full base of the fuse holders this time and also replaced the input jack assembly while I was doing the repair work. Hopefully good for another couple of decades.

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