Products > Test Equipment
Quadtech 1659 RLC DigiBridge project
DavidAzulay5000:
--- Quote from: jonpaul on January 22, 2023, 10:49:17 am ---Bravo, great job. Wonderful machine,
My original 1659 GenRad is working OK but loud fan and the keypad decal gone.
Only quirks...
1/ Keypad decal often lost or damaged....Would love to get a keypad decal/overlay as you have made.
2/ The leaded component test connector needs a lead/4 wire/BNC adapter, they exist byt rare.
I would have added 4 floating BNCs to the front to replace the test connectors for use with ext 4 wire leads or tweezers.
Jon
--- End quote ---
i know leaded component test connector is super rare
tplayne:
Sorry for the necro-post. I recently came into one of these for myself. Admittedly it is the older body style, and branded as Genrad. Date codes seem to indicate a 1984 model year but it seems totally functional. It was so odd. When I got it it seems like someone had gone through and purposely messed up all the calibrations. Up to and including setting the frequency calibration to say that because after I did a very rough calibration using what I had on hand,
tplayne:
Sorry for the necro-post. I recently came into one of these for myself. Admittedly it is the older body style, and branded as Genrad. Date codes seem to indicate a 1984 model year but it seems pretty much functional. It was so odd. When I got it it seems like someone had gone through and purposely messed up all the calibrations. Up to and including setting the base frequency calibration to zero.... somehow. When I got the device it selfchecked fine up to a "range 4 out of cal error" . After I did a very rough calibration using what I had on hand, (decade box, fluke 8842a and a scope) I was able to follow the service manual for frequency and range calibration for all 4 ranges and clear the range 4 error. Now I get range 3 out of spec but the measurement is pretty reasonable, based on my current gear.
How did you go about calibrating you very pretty rebuild? Did you use highend trimmed resistors, or just a decade box and a very accurate multimeter?
If I wanted to increase the accuracy I know I would need to get my hands on some metrology grade resistors of the specific values (the IET Labs official kit is out of my range). Any thoughts on where I could acquire such resistors. Ideally they would also specify the Q values. Usually I feel that "close is good enough", but knowing what this device is capable of, makes me really want to dial it in.
-Tom
jonpaul:
Hello: Havwe two 1689 later version of 1659, remarkable units.
Go IET /GenRad site, DL full PDF of 1659 manual.
Complete on use, performance check, repair calibration.
https://www.ietlabs.com/1689.html
Usually the 3.0V Lithium RAM backup battery must be replaced first.
Turn on Self check 2222 x means CAL constants lost
GenRad specifies a certain set or 4 VERY precice CAL resistors ($2000!) eg 24.7500 Ohms WITH SPECIFIC Q VALUES IN PPM.
With a 6.5 or beeter DVM you CAN get the reiositances required BUT need a precce RLC bridge at 1 kHz to get the exact Q in PPM.
See more info on forum for Metrology.
Bon Chance
Jon
SoundTech-LG:
Hi Jon,
I just got a hold of my 2nd 1689 as well! A complete CAL kit with case too (unused) for some odd reason the OPEN was wired as a SHORT, a mis-labeling issue.
I recently had a problem in the 222 4 error, but it was a Freq CAL issue, and now resolved.
Both 1689's full CAL'd except the for the Frequency Correction K Factor Procedure, which looks a bit daunting.
Nice both of them now agree on measuring the Cal Kit values.
Never seen aftermarket Tektronix blue on GR equipment. I think I will reserve my paint for Tektronix gear.
Not so sure I like GR baby *hit yellow either.
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