EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: home_listening on February 04, 2021, 01:35:38 am
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Picked up one of these recently, more specifically a sanctioned Taiwanese build by Topward. Dates to '83 based off ICs. Works fine but the built in test fixture is an issue for anything but larger capacitors, The legs need to enter at least 10mm or so before they make good contact with the kelvin jaws. On top of this (could be old springs in my unit) but the jaws weren't usually opening such that they didn't touch toward the other end of the component lead.
(https://lh3.googleusercontent.com/2fDGh6Nl_ChEBhkoyprMb-anTmUMtZ4VlBh7Gqg70bLynljuOhVGCvt7PcOuIklVg4sZ2CZ3Yt5DAEm0TcRTQmbgawemOU-TtgvlbPP8zEIV7n2725FFMdbRFz6wB8EnPwMW2mneImEOG77aSeJpvSjFq_rdv6Bn9FO9PBGwftyAeONKNWarPvmpyl5uJ08ygijnjvk_xmjpKNfj6Hd6BHYilqIJGab2m4sDmfx21N_tP2owRxOdZTa7axY61Ve5Jw08issLROdtqP96Ett-Qd5nxtm4npImJCa9_AN3zdigAwACewhkwulhMrj8iyxeGQAYc7fY_aPyJvi4kkB1K9X_q8_mepnzYGr42taZYaQbEreHRb0DGW26KKQ6rZbYPNGmCn6vZPHmzzNdpUZ6mJ7IHoJPWhz6EOzQAQmBjbrGIbczFuivRcbn13W1FXL2b1cDTde-e3l2va3PO2w8Fw5boyF43ZcwUxwPOAGUNzGyxiICvNIaRHS-O8if6gtPSC5Z-mod0ImvlWMdbWY5GEv3m3mFuGmb5TAFdNWacKsbQvOpbhfY-S2B0Fj4hyma1R2c2Sf8sOPOBx6_5ApREATGazGo_cWGdtzQ4wr9KVAzFWuu9GPluMa_n1sH4RpU48WEQQqTnYG-KaP53FepeDNYh2ZgHnBf-uF4e77XgISl2mgG8DXpahDi5yQA=w1380-h1840-no?authuser=0)
I had it open to satisfy curiosity and noticed that A: there was plenty of room at the front for a sortie of BNC connectors and B: the built in test fixture is screwed into the PCB, so I could potentially tap into these points without and soldering on the main board.
I decided to add a BNC 4 wire kelvin IO, spaced on a 1" pitch as thats what the older HP et al units appeared to have.
Will say right off the bat that I'm sure this has metrology implications with this unit, but I'm mostly going to just be sorting capacitors to 1% and am not that worried about actual value, usually done with tape over the panel so you can't see all the superfluous digits, so for my needs any potential degridation in quality is certain to be made up in practicality.
Holes were drilled, BNCs were fitted and some bus wire was used to bridge the shields of the connectors, Getting everything screwed in was a bit of a dance but it all went together fairly quickly. Since the jaws are designed to short the force and sense terminals, a plastic separator has to be used to avoid this when using the external 4 wire hookup. This is actually quite neat, as without the separator installed the front panel BNC terminals work perfectly in 2 wire mode.
(https://lh3.googleusercontent.com/PFzIXTgcXs1gfQ3_OhftUDjG2sWAolaRY8KFPbgHWYgZC0m9ft-lY7A8ZT8IA-Fd2xpgHo14gZxeZ2kOpzmAm8pq9d8V9GwU9m0Zvz0BofgWsL7tWel0cYVSbQ_dJ7jQ_qwVm0EHmtucZ4RGqfu9h3hYejTXa3dAMdYCkJUe6hlVmmsJk8URTzaIum1gDxtqxyGyJor5VLZFdtidiufGosgDJWQAnnzn11gPVmHFnFMIhvfWt_lDXn7opas9qLBPX9AqllKeTZPulGVMP6avjjqPIrmz3eQ5GqwPhDR42sXSRoe-sBIuGX-5Ctj46MscVwEMG2q5FctIJhHAqHkJGBpAmi6JjDBVsAF2lW0djBeZy7vn9FxlWeZO72Fn_u8D6UuLHFggc_iQfzrS6MkR1xinJ-mbgUjH8VR-AEPv0c6RWsKHE-ZJfBajjhux0Wl0C61xsYfZZwI56-W5KsJCfRZFioaazgtO1dDVlcVLsukO0gC9ECmQxrykmrSzsXB1-4AIZ0r5Anz8Jmq9eIU30F00eC99ZzBl8a72tnJlnBF9WMdj3li7I4C9ToxRyXX1H2hdNLcCb7676OuPC7iKFCRdyegPqC6DvEf2TibZ4FEgY6V8-3rfpWyTwGGQUmZSCmD69wepQa2NoAGzf3eCoBMkj0qypU0ZPiowt3pOpBIQR5BJAKt2KeqCyFUi=w2455-h1840-no?authuser=0)
(https://lh3.googleusercontent.com/Qlzai30q_badMEB0ld6h22u0lD-e8kMNXRAtv4Y0LhwgB6f4FeLTU9bAPEeM52Fji71OS7JqfnP_rPqLjGunv0IFzVYnmWUTOOq-p-b3dWTG1PBC-qhuHwrq6BWIacmlp0bi-o_4LDXAHOzCYG3T5n8dDQnaxLePODMd5LwyxomVp2VgZCd__z--8nr2KNkFjV7gSwACdEFtmLq5tolTHMtWSDsWuuvP_YCgXWQRTTxY_9JU3ivwBbqi5xFs4uO_K257WtIKW6NQq1_ok5Hz1ozIaQa1XUZ-Cwtg9DjYiOiALoAv6OAh3KAY2x6U1a99p_Z2EhH0M7gynBvAuWqjf_ytDOB7OHmDPl3Hq6k1WTr8vITtQ2mn5u_Un2JgqEXqAFt2QqK9TOzTtOtBuo4RlIKgDP7E1xmNmyuUcSsJd8HSRy9eGOhF771b0HHmzUr_8zZvXtHli33qGRc2lA4W-_mmMqp_meb1kdVDAdVdhyzI1H2Wsr_1pLHvGA-IbF-179y14EapEX2i5DB-IfCQxJCv2OmacBBAlVaMnd6Wn1C5rb9eBWHzg1k6oWrdIot_4Kh95Kyc8euGB8Y2jriazg5a7N-oCaxdBS2BIMCMxQQxaDbht6_hKcQNDYhsoQSqUZAPbtGpcNGhSGCUHg01GECeydVcu1ntK_2bpqS9_V0fVyu-ELdajqLvUqAO=w1380-h1840-no?authuser=0)
(https://lh3.googleusercontent.com/Yc9LIdEMuvcmgL7ppRjvHlj53_vgGCzPZSZMqNt4rY_ooFYP5v6hMFnlc0JMP1yXThy7H34-qQpM_ehhCmUG7FNTh5zQp17wosaAyYxKJEgmoEqhmb6o5FYcx3VU3j6AePaxKo1niDvW5gDeCb0JLLeiszWY3VC302ZuifiyZdJo0wBKxemFHUfSsMca4Hzof1_3VM5kPnUxdjlsxGRoxLGgtFfvq1qreYonnvj9tB9lyNi5bubq90sTD2tRyZbJkFo4xfsB6Iw3KYTPP-NnalMEV6DDR0bwIb9ioLeMUTngg6rDBS6bNQeaZGp_wEJ7Jfd29aN6HwzGaFyHTYaxbeyHQj-rYde5Ja685fBStuxYEX5s7yqkB6HSxiX8nHxIvPJuoM7c4sKVahZc3kw_uraO6TubJ3iVWuLNvBqLOSDms8mnnX73HptLNBfRZfY_I881dX8m674qc-OfHy22dYv2CasaAIMB3nFn7WX0QCSQglU4uEI2etCp-AtrQYEmW3ZnCjIr1iV5IuyEsPnMgK-_I8I7ScGKTml5r2WwNbeWdTVo9oMd5GmSz2g67YIRGv9SkyiBzyAymEjDTmKRCyfOQTDvIhRJwIqcru7UpnyfronsrWcpkrWXB01FZVc0E6CZFaetjuITJLsAYXVGI9zFVpYK_J6vL1-3pEyRD3mrcIAfNqBxnb6BwWW-=w1380-h1840-no?authuser=0)
(https://lh3.googleusercontent.com/TOsn5RbJypoFq-BaDzErIPs28bdGvA_IzeqtQafbOBuF-smxCykph3pJz_P-F_ln53YYecnZ4lsFvOumtyF7pMMnMN-w_1j6_8iKs5sRiKlib2wk0pHGVmous6dqzI9gqbOuwAGI_Wt2ESKAxsUZC52KdTGrsjKdwzZ7wEbWX42a5VOzYWhEnUZtWE-EhlAcMl6GJgD-sHn7Kv6Fa3esWbZqBx9av_PmI5cl0_yqjve5Y3xVZfMcVnePLjVZpPfFl8fDByD_L8Yq5bImLDsLbfLlQvv1A5E6j5KBzXhfS0E_qISIZurEwglvmHIsMud0pAZ5jLKs-xqD7DyTKXqX8Ee-DOScAYZJtVyoLEzyAr4UC2UIE-dSEYoci0_ESJkJZ8QWWpR8mUqa-0PRE7vbolmIthUsh7YxRbofew26y406CIKwbgY5r6XdQv7I5gUZ-tNtVNbkyOQezVtLkzREVEaHkXzwBJceMxhV2C5mY3cY4d3uHj51dPVWI53I-cM_w3cNMz6df73bUbD6v6SgXs5EJBONomqE9LUwTTXT1wZM7VvIHWQjVSoxRzsrcFN2pCc7ZLJAfui9KthxZ7FqYLnzWfjWE3r3iaahP8IetNuazpEnlpLRoFtqBXuJf9gLtxxGJbOAw4H05HIJA2mDRAuir-YejEL908DB3grTx46eiZbPccYLchkCgIW4=w1380-h1840-no?authuser=0)
I'm awaiting a package with some kelvin clamps to actually test this, so it I haven't been able to actually run it through it paces just yet, but I did measure a few bits and pieces and everything is in order. Residual capacitance is 1pF after the modification, I didn't measure it before unfortunately. I've been thinking about the potential for the dielectric constant of the separator to affect the readings, but I suppose as long as its consistent it shouldn't affect the validity of the relative results.
(https://lh3.googleusercontent.com/VOBMxXauEiipKHFz2MlAjROBP97WWsXbGtmnTWz5mWOWc8sBH0juFdJrT_pcZMvHcZVBr-p105T4wu8MnyqSBkea_kns3H2EtPfWKKDiNglJUzhbJhoA91MFitaiKVEOUGXizthyzzzuwdetnaWxNcjrG5jhDCpdGCfRwlJ5ENnzToW4H_K_wnijvvh86BoleeoiDg-4GWnJuTSnOJn4R8EBEIFmXgyzfzZuIMcTd9ed9UWyAyWqNMhrgvQ_7wPg2XK555RNjJ7Vsd6O7860HDYGbkvLmkUPyV557HBC8UONFzbqrDhDrT3N13skVV2pYxqbe7LPYQQvlxTolnuriRMm6c76IpNqafu_hxWq-w7vJbwEnqY-OyIKTO0ba7CYx5YmxZFkqropOF1RlCqUAAMlOKEHNyWsPayxI48UTj2SYJRU48JcY8d9scGCQYrIaQdVORUbueo6x6xjXcrgnzmD2rufgfiSmNUAzvNLBJJ3odAM-25Mwpj8lwR48ceZD-uII2B-5eq5a7SRdpW4UDrpGDqd3bICC71nOcaTbCNoN4RxSC8-ZMG2N2q8W0il1R9ZGXvtL--_LJq9TXiGsJgwPo1T6SSf9qvbyCaoC323K8FPIW_6W19Jh8B1Wm8zPCH109mTqz83VVqRnOeGgKr2bicq46aQcWm1AueInPFLofnRQR15QjMf1d4L=w1380-h1840-no?authuser=0)
(https://lh3.googleusercontent.com/k2F2jGLu71HiV40MiV3nAWiuI7AuHxZAZas_SMhIX5AJgVEicQh1XX7QIQhsRGFnMI8hN5mmkX0XSKmC2tfsxISn-iMykRM8E5oDxSYgFO66CcbK729Fb-sFgtMyd8og0DS_duGwagbWN-YT-vVljMzMagQydfnMwB7_799YkIGhZXAoc1WotO-9QmMVtFOFkkGY17d5iV6ltf_IWzQtkjU1cLDCxUggbe9jC_8fO1cQbPz0HCt78F56mmahOkMbkEjajfvKFLShPuPqqpAOsLvXxOYGwbMqYPRopWjPYSnPjjMIfZIlFEdOXJlkzudn25bBnMzESMLk29H3J8NJmgcm8gjNo_bN_ZH7H9C7rl_vFBLajag8FBxrecECXANB7XbaxYBfupETuJsWB7k6P10iEmroAV5X2i7FiayYiQGRIGdcBrnIFT2_pPcfBw7FHmmYDXfNjTuyU5-MGlUtkBKV5Bh1NvKOYg8TzInsUwZkDov6dyGbs2CVN8onRhCNtwBgRbsh7CgisgS_BxKOLbeFULUb-QlUfw1PtLy1YmZ_drjHCUgIoYGrphVoGxA4rzAz-DqDaJyXVbCzrmiSggcNa63wldum1fZx6cmqAUFXOYNlYmCesAllwg-NHis4ijWZN_SPdM17OAIELH0gmMk4ZxcWqmDSsaorb8V1nLmjSHHwmgsf4pJWlBD_=w1380-h1840-no?authuser=0)
(https://lh3.googleusercontent.com/Cb7y5Dv8oVmvyMyOkgReKINpS52-HXcjYBCIdzDuAYZpKX5mpnC45LEWis9d5GsQjY8rXWS0SJKLp1s91bQk2Ga-qWPUw3pcDSJFIkR1-NlD2idyzbmwe_V8OUq4u_w24ClqSeL3q4sJ5f5FrQcgd_xIX4JPZ28GF3vnWQkxDIf9NUPLdVZriuK9hrmJ2i7pkkHtQGVeFzB0LSj5mFiapllFgpXCuikx9ELaYov4esNUCSMHwKbC1xQ6ZNox65fBpCTdcugpIpsPKMjUdYGktJBPqrhabnlL4LVLHSXJail93WLPejCY1fbTJzeFDWRRah0hsI9P_7nn_N3ufvkP172d4cK9N1wsrjg3z45aVQlD0C8jZezqbWZ8azVBEG1mVGUxhpRKt9B4JdRuQ4OO8nPQaqJEGmIzDK0C4j3-8MfrO93p1J_bKVsKlgqbhWcG4e71z3qAuYUvmGamHDGjxGhEK85cnF0ZSJHrofVwN8-jw_snxbkruFE0f42MvSfqdS2mIpwribqXnj7ALA8Y-aka5mMY-pS3sTUWlago19iULrgUEfEfjGq9RzZeJbMFOD0ex9cpOEXzn4Dac-yPF9Hku8v6JXkRFly---F1B-hV6_eVQZixXizF12FvcF_A7nNTCMyJsv77eqrEYinbiqDAbRYX6-zmpqCew9RJnfpDzIMwfxCQGKTn3yDj=w1380-h1840-no?authuser=0)
These are cheap LCR meters that are a pleasure to use, the precision resistors are stable ceramic substrate cadock units and there is no calibration whatsoever. The EEPROM program is available online and as its mostly 4000 series logic there isn't any great reason why you couldn't keep this going forever. This took an hour and should add more flexiabiliy to it. Mine seems to be ex Australian Army, The faded sticker on top reads "Developmental Investigation Laboratory".
(https://lh3.googleusercontent.com/urmmB_0nNpiOfFkRegtk6aBqPhSF0EsEoj2XKaXuqxi_vnl7gDyMBEypIj8e30pDPjF6Mx6HMwtucDazEFQSPW14SZd4FrA2-pq2jnbJFkeiUClGEAy-7SMVz5tWhnDJIXAYJexNmE7qwphR6xsAwfDPCvVYn4CffX52IQI5z8wE6fgQAZcfTLB1ljYiNpqMoJaB9ndacuW05jPRA2a_Dp9zSUYKnqVG7RMHEaPzpy0cHwFkBJ8bQ9Uffu211IvbJBRltb1BzsBpAd0MGOfCMJt1rt1CEYUtafM39tgnQBxKXtKs34OoMVpMTotQlBSDnQ9qo1i5Qk4yAlT1wrTLWZmVvz644E_BnrfXTn5cfkhtk15N1BTjQpMuBfoazXpKbpmim0XnwHjP12ZlXrjB33xQ5fvCLxnUsz5k_whDC9cAxoYvgy8huJS9kotFYXWX7KTYPYSeibxus1mZUk_o-QbRTXo3eV3P5Ldw0bo4yySSYoCbGpjEBR31ThXQl2Kp2pW1A9qpVhAWc-tdrFRrhuHMTF8A1083RgZXL-6bkj-kenThngxvmki69QSXvHbPlHNcNglOgtpT2UJPlSvlg-6jWQR-EEhhxe9EXPXRJEQ_kHMmoP8ZcmG18WkSqE2Gyx_zxp8NkOzsoEBn2UPlaLDK4N8EPSLnMYt4v_IoezvVRQrijBnfwCU98unq=w1380-h1840-no?authuser=0)
(https://lh3.googleusercontent.com/fEKN0SiiNUhExndL0ndYTagJjEWsN2KLY9ubD9bvPYUgdSGK_fDtXXe6phY81eIbidEuFfH4DABU_z6bVAdpd5azVeSpyLEcpg5HoZ0Gze3FT7VXKB86XW3tlmgE0dnFPHjFxBMfHtNuri2t-MBNw1X5J5LhUK96jN5LfipRAtW7BhlgnrJD5VO9rARTjBP0X0Xn-AHV-HKv3iAvyBvLrcy34Zrf-zbFzIUuL7EPy5BCZVUMMnTpS1ucGdexlIyGint58IOUbEswkCL4nYdfOEoBZ2-Vuy8ntwSCE6dty_duoyljPblyj972e2PQrQb9RX3oPoMgxT6mZMBroc8DY4ZgXABWYhGRHzXsscWTnLTJ0qyEpoyFHk6uexIrMUFeOF0xQvSElghLTNMEM9oAUXqJWpASTX-FYulpMl8pUu_-S_-2uy5fOOYDhSg8UlKCH0bcmhpCDiHnA4UipZUqVWm_WZpVHHP12Ho9CqnvmOdxO7UBjBeK1JfV9Mh2iKyCVFsyBRi0nQNZFzQwgRuf5hIV7Q0SarhyuPDy_gGSzxO-ryIEAq0krNohpTksoOA9V5Z70uSuXE4WqFmrInikO6IxeIH_d3g-MavfM-inwOlJR_I9T-U9WvMS27QX5EkF9Id_qNfZGaTq9YLyeRjsvAj7dsyyRhqcsK2QpwjLvFL_whehlYV9FKia-gOT=w1380-h1840-no?authuser=0)
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All pictures are dead :(