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I have a Heathkit IB-2 impedance bridge that was given to me. I have no assembly/user's manual for the unit. It powers up OK and seems to be functional, but I have no idea how to use it without a manual. Does anyone have a manual they could scan in and send me via e-mail?
Try googling the make, model and the word 'Schematic'.
I have the schematic. It was really the calibration and use information I needed. I found a copy of the construction and use manual for the IB-3128, a later version of the unit. It is still virtually the same inside and out as the IB-1, IB-2, IB-2A etc. The IB-3128 was still using the 1L4, 1U4 vacuum tubes since the circuitry appeared in 1948. I haven't checked to see if new tubes are still available or not. They were designed for use in battery portable radios before the advent of transistors. They have low current drain and very little heat generated by operation, so they tend not to cause drift in oscillator applications.
The manual for the IB-3128 explains in detail how to calibrate the unit plus how to use it, so I am set to go now. One advantage of the IB-3128 schematics is that they show the function switches for each type of test on individual schematics for resistance, capacitance and inductance testing which helps in understanding how it works.
I discovered that the CRL Switch Dial (the one at the upper right side) which has numbers from 0-9 had a crack in the plastic where the set screw was located. It would slip on the shaft and the set screw could not tighten enough to stop this. I finally used a small round file to rough up the shaft surface and the inside of the knob, made sure the switch was in the "0" position fully counter-clockwise and pushed the knob onto the shaft (with the "0" aligned with the pointer) with a small drop of super glue (cyanoacrylate). After just a few sedonds it was firmly attached and I screwed the set screw down against the shaft for good measure. After this the unit was fully functional and worked as designed.
Someone years ago had attempted a repair to the knob by winding a piece of hook-up wire around it, tightened it and soldered the wire, then had added model airplane type cement to it. That was not successful in the long term.
If it ever breaks loose again I have a plan "B" in mind - order a suitable 1/4" shaft knob from Mouser Electronics, drill out the top and fasten the OEM knob to the new knob with small screws, then use the set screw of the new knob to fasten to the shaft. Mouser has aluminum as well as plastic knobs. They even have some plastic knobs that are the same shape and size as the OEM knobs used for the Generator Level, Generator Switch, Detector Switch, AC Zero Control, Function Switch and Range Switch.
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