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  • EEVblog #430 – Fluke 91 Scopemeter Teardown

    Posted on February 27th, 2013 EEVblog 11 comments


    Teardown Tuesday.
    Inside a 1994 vintage Fluke 91 Series II Scopemeter.
    Extended commentary on PCB Wave Soldering

    Service Manual
    TDA8703
    74HC4316
    TLC27M2A
    LF453
    S83C196KB

    Photos HERE

    Forum Topic HERE

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    • Tom

      Unfortunately PCB wave soldering video is private.

      • http://thisone fred

        Why is the wave soldering video is private?

        • Tom

          I think I was trying to watch it while it was still uploading…

    • http://www.eevblog.com fred

      Why is the wave soldering video is private?
      If this get published twice it’s my computers fault it stutters sometimes

    • Fredrik

      Isn’t the Fluke scopemeter orginally from Philips? Then made in Holland seems logical.

    • http://EmbeddedDreams.com Njay

      Good work!

      Did you noticed the dual footprint on the memory chips?

      The ADC’s datasheet says 40MHz *minimum*. Maybe Fluke was hand picking and overclocking their chips. If you have the time, scope the clock inputs (pins 16 and 17 of the TDA).

      Cheers!

    • Nasos

      The 50MHz of the spec is the bandwidth and TDA8703 has less than 20mhz bandwidth, and bandwidth is something that you cant overclock… is like an rc filter on the input of the ADC… So i think to posibilities
      1) they colect ADC from the production line with better characteristics…. (and also they overclocked them)
      2) i think the most possible…. The unknown custom chip is an analog sampling memory chip that it has 50MHz ΒW and high sample rate maybe 100MSPS or even more and afte the sampling the TDA8703 reads the samples… Also thats the reason why there is not a fast memory chip ( and counter or asic) or fifo near the tda8703.
      That is not something unusual… I think most low end tektronix oscilloscope use this technique… (and thats why they have small sampling memory like 1K) i dont remember the model that has a sampling rate of several 100MSPS or even 1GSPS using analog sampling memory (asic) and then reads the samples with an mc10319 (25msps adc)

      • f4eru

        you can also compensate the bandwidth, up to some point, with HW and/or SW compensation.

    • le mazou

      murata ref is a BNX002-01.

      > 40dB (1MHz up to 1GHz)

    • f4eru

      Dave ! test it to 50 MHZ !!

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