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  • #16
    I was lucky...or at least I think I was...I managed to pick up a Sencore SC3100 for 50 bucks....everything seems to be working except the sweep circuits...the bean finder does work but shows the beam as being too far to the right you can't see the dot as it is off the screen but it is there as you can see the far right side of the crt showing some signs of light....This unit also came with all the specialized probes , owners manual and all schematics....picked it up a few days ago.....whenever any push buttons are pushed, the corresponding indicator lights all light up....so I am hoping the only thing wrong is in the sweep ckts......

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    • #17
      Galaxiex
      Pretty cheap too. Hella thanks.

      glebert
      Jesus, what a simple hack.

      bsco
      Sounds like you got a steal. Congrats brother. Its sweeter when you aquire something old and it comes with all the swag. I've got some old Pioneer headphones that I love still in the original box. Not as cool as your Sencore though.

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      • #18
        This dummy load is so cheap its hard to ignore. Any reason why I shouldn't trust it?

        https://www.ebay.com/i/312685241127?...waAmeuEALw_wcB

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        • #19
          Originally posted by DŁTerra View Post
          Galaxiex
          Pretty cheap too. Hella thanks.

          glebert
          Jesus, what a simple hack.

          bsco
          Sounds like you got a steal. Congrats brother. Its sweeter when you aquire something old and it comes with all the swag. I've got some old Pioneer headphones that I love still in the original box. Not as cool as your Sencore though.
          you don't normally get any good test gear around these parts...even not working...every now and then something comes along but you got to jump on it when it is available...hopefully I will get to look into the issue after I get some outstanding repairs out of the way.....

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          • #20
            Originally posted by DŁTerra View Post
            This dummy load is so cheap its hard to ignore. Any reason why I shouldn't trust it?
            I use resistors like that, but keep in mind that the power rating almost certainly assumes that it is mounted to a heatsink, perhaps with a fan. Also the shipping is just forever slow since it is from China. You may be able to find same thing from US seller for a bit more money that will be much faster.

            I usually make a bank of power resistors with at least two parallel paths so that if one resistor blows the amp isn't seeing a dead open.

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            • #21
              Originally posted by DŁTerra View Post
              This dummy load is so cheap its hard to ignore. Any reason why I shouldn't trust it?

              https://www.ebay.com/i/312685241127?...waAmeuEALw_wcB
              That is cheap.....I might take a chance and order some....

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              • #22
                Originally posted by DŁTerra View Post
                This dummy load is so cheap its hard to ignore. Any reason why I shouldn't trust it?

                https://www.ebay.com/i/312685241127?...waAmeuEALw_wcB
                You can get resistors like that from DigiKey.
                Fast shipping and no need to order from China.
                If it ain't broke I'll fix it until it is...
                I have just enough knowledge to be dangerous...

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                • #23

                  Every time I've ordered cheap passive components direct from china via ebay, I've regretted it. I ordered some 2W sealed "RV4" type pots, and they were total pieces of shit. Even after being reimbursed, I still feel like I wasted the money. Also, ordered a kit of assorted carbon film resistors. Interestingly, they all measure dead on their resistor value. But they nearly disintegrated when handled, and had the worst quality magnetic leads.

                  You can buy quality products for very low money if you know where to look. I'm going to let you in on one:
                  Newark.com - Deals

                  Newark.com - Fixed Resistors RESISTOR BLOWOUT SALE!!!
                  If I have a 50% chance of guessing the right answer, I guess wrong 80% of the time.

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                  • #24
                    Originally posted by DŁTerra View Post
                    This dummy load is so cheap its hard to ignore. Any reason why I shouldn't trust it?

                    https://www.ebay.com/i/312685241127?...waAmeuEALw_wcB
                    A few remarks about these power resistors:

                    I use a couple of them in a dummy load and bought some more as spares.
                    Reason was form factor not cost.

                    These 100W rated resistors are about the size of 50W Dale types and about 1/4 the size of a 100W Dale. So I treat them as 50W max resistors.

                    Both mounting holes are on the same side and the seat /mounting face tends to be uneven. Both prevents good heat transfer to heatsink.
                    I ground the faces flat and used thermal pads.

                    In my application the resistors are mounted to an aluminum plate and never see more than 25W.

                    I certainly don't think these can take more than 50W continously even if well mounted to a large heatsink.

                    All these aluminum encased power resistors require adequate heatsink mounting. Observe power derating curves and case temperature.
                    Last edited by Helmholtz; 11-23-2020, 09:20 PM.
                    - Own Opinions Only -

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                    • #25
                      As Helmholtz pointed out, these '100W rated power resistors, being same size as 50W rated Dale power resistors....here a couple images of the standard Dale 100W power resistors that I have mounted onto a Wakefield finned heat sink (eight Dale RH-series 100W/4-ohm resistors, wired in series for 200W/8 ohms). That is sitting atop a 4kW 8 x 4 ohm/500W fan cooled heat sink assembly.

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                      Logic is an organized way of going wrong with confidence

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                      • #26

                        nevetslab has all the best toys.

                        When I was building mine, the 250W wirewounds I was looking at were cost prohibitive.
                        So, I build mine load box (switchable) to handle 16Ω/300W, 8Ω/300W, and 4Ω/300W. or all 3 in parallel for 2Ω/≈550W.
                        Using that Newark overstock link I posted, I build mine for about $38 for the resistors and rotary switch.

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                        If I have a 50% chance of guessing the right answer, I guess wrong 80% of the time.

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                        • #27
                          The days of wonderful 'prizes' that filtered down from the Military and industry in the days before ebay, so many of my acquisitions came from TRW Amateur Radio Technical Swap Meet in Redondo Beach, as well as General Dynamics in Pomona back in 70's forward. I had purchased every 2 ohm/250W Dale power resistor one vendor had....must have been around 60 of them, and from another, these 4 ohm/100W Dales on the smaller plate. That swap meet has turned in to a 'junk-yard sale' as all the good stuff and quality vendors long since left to use ebay and the internet to sell their wares. Even all the good surplus stores in the Southern California area have disappeared. But, never give up searching. Every so often, I'll browse, and find an undiscovered treasure for dirt cheap and luck out.

                          Nice load box!!
                          Logic is an organized way of going wrong with confidence

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