fluke 606xA  adjusting the 10MHZ synthesizer oscillator and drift. - Page 1
Forum section: electronics / repair

author: charlyd
author_rank: Frequent Contributor
timestamp: March 12, 2018, 07:31:04 pm
content: hello i have a question about the 10Mhz synthesizer oscilator adjustment for a fluke 6062A ( no option 130 & 132 installed ).how stable is the 10MHZ Xtal adjusted with C240and how is the drift on adjusted with R230 ( mine keeps on drifting to the right and then to the left??)Who has a 6062A ( or 6061A ) without the options high-130 and medium-132.did you ever troubleshoot this part of the generator...if yes..suggestions wanted... what is normal behavior and what is not?

author: SaabFAN
author_rank: Frequent Contributor
timestamp: March 15, 2018, 12:37:36 am
content: If I understand this correctly, the adjustable capacitor is only a coarse adjustment. The fine adjustment and stability comes from chip U70, which is a analog switch.Without further information, I suspect the problem in 3 places:- R230 is toast. Happens to Potentiometers when they get old.- U70 doesn't select the right source of the adjustment-signal.- The select-logic for the reference-signal isn't working correctly and connects what seems to be a PLL to the Oscillator-Control.I'd start with the voltage at pin 11 of U70. If that voltage is not constant, you got the culprit. Next would be Pin 4 of U70 - Check that for the right level. The DG301 is available at Mouser, including datasheet:https://www.mouser.de/ProductDetail/Vishay-Siliconix/DG301BDJ-E3?qs=sGAEpiMZZMtxrAS98ir%252bs0szLGzxh%2fuDaZXwrGmy8Ek%3d

author: Stray Electron
author_rank: Super Contributor
timestamp: March 15, 2018, 12:59:12 pm
content: My 6061 (std model) shows very good stability against my HP 5343A (option 004 & 011). But I'm n0t sure how accurate they are until I get a GPSDO to check them against.

author: charlyd
author_rank: Frequent Contributor
timestamp: February 08, 2019, 10:38:37 pm
content: sorry it took a long time.. to be back.. but i started picking up the problem again: this is the schematich from the 10MHz part.U70 output pin2/pin13 output is very stable.so ? if there is the problem… has anybody ever had broken varicap CR22 & CR28 diodes..?(I am also still looking for the "130 High Stable Reference board" if somebody has this board please let me know.)

author: charlyd
author_rank: Frequent Contributor
timestamp: February 17, 2019, 10:29:00 pm
content: so last weekend i took the board out it took me 45 min.then i placed the U70 on a socket and replaced CR22-CR28 and the 10mhz BLiLey BK3-1B crystal.tomorrow i will have a look for the adjustment of R230 against the drifting.. but from what i saw it is not yet gone….

author: charlyd
author_rank: Frequent Contributor
timestamp: January 02, 2020, 09:36:22 am
content: Hello can anyone tell me how accuracy & stable this fluke / gigatronics 606xA unit is.. for example on a- 500Mhz what is it allowed to drift?- 2.1GHZ (for 6062A) what is it allowed to drift?and also for the power level.i am curiuos what i can expect, and then not what i can read in the specs, but what these units really do.we call that not in theory but in practice.

author: wn1fju
author_rank: Frequent Contributor
timestamp: January 02, 2020, 06:06:48 pm
content: As far as frequency drift is concerned (with the standard crystal oscillator), my Fluke 6060B drifts quite a bit until it is warmed up.Fluke 6060B 10 MHz reference output jack on back panel feeding an HP 5335A counter (with ovenized oscillator): From a cold start, I let the 6060Bwarm up for one hour. The unit then drifted about 16 Hz until it seemed to stabilize after four hours. Then the drift was about 0.7 Hz for the next hour(with about 0.1 Hz the last 40 minutes).The spec calls for +/-5 Hz (0.5 ppm x 10 MHz) drift over one hour. I believe the 606x units will meet that spec comfortably - but only after it has warmed upfor at least several hours. The expected drift at any arbitrary output frequency would then be less than 0.5 ppm times the frequency.I didn't check the amplitude drift. I would expect it to be neglible. And since the accuracy spec is +/-2.5 dB, any drift would be trivial in comparison.

author: charlyd
author_rank: Frequent Contributor
timestamp: January 04, 2020, 01:57:27 pm
content: thanks to all replies great work guys..! this brings me to do some more testing.- picture 1 i powered on the unit in the 500Mhz position and this is what happened.- picture 2 i connected to the REF out on the backside- picture 3 i took the ref out from my 53181A counter and connected to the ext in ( backside of the 6062A ) switched the 6062A in 500Mhz( rock stable)is that a known issue with the R230 and U70as SAABFAN wrote above.now my ovenized osc. is on J110 ( added the schematic again in just a better quality)

author: charlyd
author_rank: Frequent Contributor
timestamp: January 15, 2020, 09:46:45 pm
content: after replacing U55. - DM74S04N.the drifting was solved, even without option 130 after warmup of course 15min. only last digit.the power out is noisy in the lower freq range. details will follow.any suggestion?

author: charlyd
author_rank: Frequent Contributor
timestamp: January 25, 2020, 10:42:08 am
content: i so when the 10Mhz was fixed, i discovered below 245Mhz my signal was not stable or let s say very noisy. After hours i found a open circuit arround the LPB filter. then my signal was great again. that nearly finished the project.reset  result: 30 - 300.000.00 -10.0----------------------------------------------------------------------------------pushing the status button i saw : 000 000 000 -> Job done i thoughtbut no, i still have an amplitude issue.i am curious if these units when i  status it displays 000 000 000 and i dont have a "uncal".. butmy amplitude is very low between 62.4mV - 251mV below 62.4 it is ok and above the 251mV. i did test the latch part and the relays kick in when needed.anybody experience with a problem like not having a stable amplitude..

author: SaabFAN
author_rank: Frequent Contributor
timestamp: January 27, 2020, 09:43:18 pm
content: According to this pagehttp://wera.cen.uni-hamburg.de/DBM.shtml62 to 251mV is a range of pretty much exactly 12dB.So I'd say there's an intermittent contact in the attenuation-part of the 12dB mechanical attenuator.There are a few videos made by TheSignalPath on Youtube, where he shows how these attenuators work and I think he also repaired one or two.You can probably verify this by gently hitting the attenuator with the grip of a screwdriver or rubber hammer - you should see changes in amplitude if the RF-Switch has a contact-problem.

author: charlyd
author_rank: Frequent Contributor
timestamp: January 30, 2020, 02:46:38 pm
content: hi today i too out the att. relay block and it seem 1 off the relay response really weird.. time for a relay swap..so i need 1 relay but maybe if the price is not TOO high swap them all.we wil see.WANTED..i am in the need of aGENICOM 3SDS5002G1relay they are difficult to find so my shout out here if somebody can help me out and sell 1 or more of these relays or compatiblethey are typeDPDT - 18v coil 880 Ohmi will add a picture of the relay ( under a microscope ) and the output board.if somebody has an output for sale from a broken fluke also ok.please PM me if you can help me out

author: rf+tech
author_rank: Frequent Contributor
timestamp: January 30, 2020, 03:15:13 pm
content: Take a look at Teledyne EMR selection Guide, many high-reliability metal-can options available, for DC to a few GHz applications.https://www.teledynerelays.com/Datasheets/EMR%20Selection%20Guide.pdfIt will be necessary to determine if the original relays are latching or non-latching.RF+ Tech

author: charlyd
author_rank: Frequent Contributor
timestamp: January 30, 2020, 05:40:16 pm
content: rf+tech, thanks for you reply. if you mean by latching if the relay click in at the right moment. yes i checked out the whole table.but what i suspect the last moment is, can it be that as per latch the output at the beginning of the attenuator / RPP assembly . ( so the output) is regulated,probing at that point i get :-> = stepping down in AMPTD2.207 volt -> 620mV  1.1670 volt -> 589mV  1.116 volt -> 565mV  1.097 volt -> ...and on...in total there is an attenuation of 138dBm 6 - 12 -24 - 24 - 24 -24 -24 the last five 24dBm i can toggel with SPCL 83 - 86can it be that one is a bit off? so i can correct it ( sort of reprogram it... anybody experience with that ? there is also a SPCL 90/91 95/98i did NOT dip any switches like #6any tip is welcome

author: rf+tech
author_rank: Frequent Contributor
timestamp: January 30, 2020, 06:55:54 pm
content: Non-latching relays must have power applied to the coil, to maintain N.O. contacts in a closed state and vise versa.Latching relays contain a small magnet, to maintain contact state. These do not require the coil to be energized continuously. Some latching relays contain two coils, one to close and the other to open. Single-coil latching relays require reversal of DC polarity to the coil, to change state.As for the remaining part of your post: mixing volts and decibels makes for difficult interpretation of data. Seriously, please express all RF measurements in dBm for absolute levels and dB for incremental differences. Doing so will reveal details at a glance, without the need to reach for a calculator.Also, when using non-obvious mnemonics, show the rest of us the courtesy of explaining their meaning. RPP?? SPCL?? WTHDTM?RF+ Tech

author: charlyd
author_rank: Frequent Contributor
timestamp: February 10, 2020, 09:44:33 pm
content: thank RF+tech, thanks for the tip yes indead i need to keep it to one measurement value. i didn t have a Power meter yet so i couldn t go for 100% dBm but now it would be much more easy todo.the codes  stand for Special function mode. and RPP assembly is relay driver board.

author: charlyd
author_rank: Frequent Contributor
timestamp: January 09, 2022, 10:51:02 am
content: Hi the topic is old but i never did a follow-up on it.. i got myself an other attenuation/output board like in post #11 and didn t have the time to swap it still.will be continued....