Wayne-Kerr 3245 Precision Inductance Analyzer - Page 1
Forum section: electronics / general

author: jonpaul
author_rank: Super Contributor
timestamp: February 14, 2022, 06:30:35 pm
content: Bonjour a tous: Our vintate Wayne-Kerr 3245 Precision Inductance Analyzer is 1982 vintage and has a 7" CRT.http://manuals.repeater-builder.com/te-files/MISCELLANEOUS/WAYNE%20KERR%203245%20Operating.pdfVery versatile unit and basic for our transformer manufacture.The CRT suddenly lost sync and was slowly growing dim, checked the PSU, fine, the PCB connections were OK but all the carbon comp trimpots on the dispay CRT bpard were scratchy and intermittent. After contact lube and exercise, it is fine, and the CRT still bright and in focus.However the convergence pattern is dlightly distorted at the left side of the screen.we have the service manuals but the CRT HV and sweep/video display is not in the manuals as several UK vendors made these.If anyone has access to the CRT board schematics, alignments, etc it will be appreciated!Many thanksJonPS: Incredible that decades after last CAL, it is STILL IN CAL!

author: 1audio
author_rank: Frequent Contributor
timestamp: February 14, 2022, 06:48:07 pm
content: It looks very similar to the ESI Videobridge. Most of those display modules have similar circuits and I could provide what is in the esp module if that helps.I would like to find an LCD module to replace the crt but most new ones are digital interfaces.

author: jonpaul
author_rank: Super Contributor
timestamp: February 14, 2022, 08:48:21 pm
content: Rebonjour 1audio, unfamiliar the ESI, perhaps they liscenced or copied the WK design.I re-read the large bound service manual and discovered I overlooked the two versions of display board, schematic and adjustment proceedure!As the yellow phosphor CRT is bright, in focus I saw no need to replace with LCD.The instrument is very vintage and unique as is......Bon chanceJon

author: 1audio
author_rank: Frequent Contributor
timestamp: February 15, 2022, 01:04:46 am
content: It may be the other way around. The Videobridge dates from 1981, the Wayne Kerr from 1986. They are similar. The Wayne-Kerr has some featires for transformer measurement that are not in the ESI.

author: jonpaul
author_rank: Super Contributor
timestamp: February 15, 2022, 01:14:18 am
content: 1 Audio, great info, indeed the WK is dated mid..late 1980s.The transformer ratio function is unique, and very special.It is now working perfectly, except for slight distortion in the left-hand corners that doesn't affect the displayed screen.I.am not brave the to fiddle with the CRT magnets to adjust the beam pattern.....Jon

author: HalFoster
author_rank: Frequent Contributor
timestamp: February 15, 2022, 12:22:18 pm
content: I don't have it where I can open it up to make sure, but I have a 6425 and from your pictures it seems like it may be very close. Hopefully these help-Hal

author: jonpaul
author_rank: Super Contributor
timestamp: February 16, 2022, 09:44:44 am
content: Rebonjour Hal Foster:I discovered that both types of video board schematics, in the 4 cm thick bound paper service manual provided by W-K! I had overlooked them before.Yesterday using the CODE 0.2 alignment grid, I was able to adjust every control for a bright focused display.The focus trimmer range is very narrow. The linearity coil adjustment is super sensitive.I could rotate one of the CRT neck control to adjust the pattern distortion, but did not dare to disturb the ring magnets arrayed around the CRT neck, hedl in place with hot melt glue, as the pattern was good enough in all areas of screen except left top/bottom corners.Anyone that has adjusted CRT ring magnets on a CRT neck, please comment!Going again thru all ranges, bridge frequencies, levels and calibration Z L, C, using CAL standards, this 1980s vintage machine is still in CAL better than the 0.05% specs in every respect.BRAVO to the Wayne Kerr designers so many decades ago....What a marvel!Jon

author: HalFoster
author_rank: Frequent Contributor
timestamp: February 16, 2022, 05:30:57 pm
content: Oh, I agree completely! Mine is about 10 years or so out of Cal and still is much better than spec (which are very good to begin with.) I sold both of my HP 4274A meters as it was better than both - one of which had recently been calibrated - and was easier to use. The only issue with the WK 6425s are that the test lead kelvin connections are different than normal - it is detailed in the manual; I don't know if that is the case for your 3245 but it makes a difference with the 6425.Hal

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 16, 2022, 11:14:11 pm
content: If the ring magnets are not loose. I would think that moving them would not help.They are typically adjustable with the pots. I think you have tried that.I do not know your unit but this sort of thing is common in these CRT like things.If these coils come loose, it suddenly changes the pattern on the screen.

author: jonpaul
author_rank: Super Contributor
timestamp: February 17, 2022, 01:06:55 am
content: Wallace many thanks, yes all ring magnets are tightly bonded with glue, the pattern in good convergence, except the left hand corners.I will check the trimpots and linearity coil adjustments again.Jon

author: 1audio
author_rank: Frequent Contributor
timestamp: February 17, 2022, 07:18:59 am
content: As an experiment I just ordered a 5" LCD car backup monitor ($25) to see if its compatible with my ESI. Replacing the CRT with something like this will remove a lot of heat. It may work in some other places as well (My Wavetek FFT plugin)

author: jonpaul
author_rank: Super Contributor
timestamp: February 17, 2022, 03:44:39 pm
content: 1 Audio: The enormus 15 kg WK 3245 has a linear PSU and regs on a massive HS on rear panel.Even after all day op its barely warm.Power consumed is only 70W.So in this case the CRT is fine, and lends a fine vintate appearance to the instrument.Keep me informed your progress on the LCD replacement...jon

author: 1audio
author_rank: Frequent Contributor
timestamp: February 17, 2022, 05:07:42 pm
content: The ESI has a noisy fan so getting the heat down and the startup quicker would be good. I have 3 of them and have had to futz with the CRT monitors in the past. I have a fair amount of experience with CRT's which is why I want to replace them on these instruments. In my experience anything with high voltage will tend to fail.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 17, 2022, 09:30:05 pm
content: Just a goofy idea... perhaps put a small magnet on a non conductive stick and put it near the adjustment coils to see if anything changes?But if is usable and the distortion does not affect any information on the screen perhaps leave it alone???

author: precaud
author_rank: Frequent Contributor
timestamp: February 21, 2022, 02:37:28 pm
content: I tried a couple of those LCD displays that have composite inputs with an Anritsu MS420. The problem is, unlike crt displays, they don't provide H or V centering adjustments and only ~ 80% of the image was on the screen.Quote from: 1audio on February 17, 2022, 07:18:59 am

author: jonpaul
author_rank: Super Contributor
timestamp: February 21, 2022, 04:30:45 pm
content: To 1 audio, we design and manufactured HV supplies for crt avionics, the potted 12 KV supply never had any failures in years of deployment, 10k units.HV failures can be analyzed and reduced by careful design and components selection.To Wallace, agreement 100% after the several rounds of adjustment the CRT convergence grid is fine,if it ain't broken don't fix it!The WK is now happily restored to the measurements bench.Case is closed,Walked away from another one.....(:-:)Jon

author: 1audio
author_rank: Frequent Contributor
timestamp: March 02, 2022, 08:35:24 pm
content: I'm really torn about upgrading old CRT displays. The Monitor I bought was dead on arrival and I got a refund.There are instruments where the display upgrade makes a lot of sense. Some HP spectrum analyzers and VNA's will benefit. On these other less daily use devices it may not be a good ROI. However a failure on an unobtanium component is a different story. I'll keep looking for a decent solution.