Wavetek 2410 RF generator rehab. - Page 1
Forum section: electronics / testgear

author: Housedad
author_rank: Frequent Contributor
timestamp: October 04, 2018, 10:46:58 pm
content: I recently acquired a Wavetek 2410 RF generator. 10Khz to 1.1 GHz. It was designed and marketed back in 1990. Big beast, Digitally controlled with a simple 8 bit processor, DDS/PLL, and a linear power supply. Picked it up off of Ebay for $180, and wanted to try to get it going.I ordered a scanned copy of the manual, which includes schematics, BOM's, troubleshooting and calibration sections.I'm studying for my Ham Liscenses now and want to get equipment to bolster that hobbly. The 2410 is probably a bit overkill for it but what the heck. It is cheap and I might be able to get it working acceptably.

author: Housedad
author_rank: Frequent Contributor
timestamp: October 04, 2018, 10:52:49 pm
content: The 2410 showed up yesterday. Looks in fairly good shape. I powered it up and it works. Had to have it load default settings to get rid of a unlevel code after having it do all of it's self diagnostics.I had ordered a couple of N to BNC adapters and they came in today. I've only had a few minutes to check it out.I did find a couple of issues though. The Time base Out is not clean. It has spurious things on the waveform.The main output of the generator shows a waveform, but it looks like there are several waves being produced at once slightly off phase and amplitude making a thick trace. When I show it as single trigger on the scope, I see one nice sine wave. Keep hitting single and the phase changes back and forth a small amount.Looks like the time base has issues.Pictures in a few minutes.

author: Housedad
author_rank: Frequent Contributor
timestamp: October 05, 2018, 01:25:37 am
content: Here are some pics of the case and insidesInsides first

author: Housedad
author_rank: Frequent Contributor
timestamp: October 05, 2018, 01:29:32 am
content: The outside is rather mundane.Front and Back panels:

author: Housedad
author_rank: Frequent Contributor
timestamp: October 05, 2018, 01:34:01 am
content: Waveforms:If I have them all in order rightFirs picture is the internal reference clock outSecond is internal clock out when using a external clockThird is RF out with internal clockfourth is RF out with internal clockfifth is RF out with external clock 10MHZ sine 1vpp

author: xrunner
author_rank: Super Contributor
timestamp: October 05, 2018, 01:50:38 am
content: Start inspecting the circuitry providing the 10 MHz ref. output. Looks like a bad connection or coupling or functional issue. Did you get any schematics or service manual?

author: Housedad
author_rank: Frequent Contributor
timestamp: October 05, 2018, 01:58:23 am
content: There is a person that scans old manuals on Ebay. I ordered one and it has full schematics, part lists, circuit descriptions, some troubleshooting and full calibration info. Even full isometric drawings for the chassis and where everything goes.Operation and service manual all in one. Without it, my simple skills probably would not have gotten this far.

author: xrunner
author_rank: Super Contributor
timestamp: October 05, 2018, 02:03:12 am
content: Quote from: Housedad on October 05, 2018, 01:58:23 amCool.I had a Marconi RF signal generator that wouldn't reliably accept the external reference. Turns out it was some soldered connections that were going bad. As soon as I re-flowed them it was OK. Good thread should be interesting to follow the progress.

author: Housedad
author_rank: Frequent Contributor
timestamp: October 05, 2018, 02:06:04 am
content: I'm having a blast. I haven't worked on a real electronics problem like this in years!!!I need to set up a spreadsheet and start documenting all my measurements and troubleshooting. Just like theOLDdays long past.

author: Housedad
author_rank: Frequent Contributor
timestamp: October 05, 2018, 02:07:18 am
content: Quote from: xrunner on October 05, 2018, 02:03:12 amoh, Lord, let it be that simple!

author: Housedad
author_rank: Frequent Contributor
timestamp: October 06, 2018, 05:00:24 am
content: Starting tomorrow, I'll pull the oscillator reference box, disassemble it and inspect the board.I ordered a DE 5000 meter a few days ago and when it comes in I can do a better test of the board components.Sleuthing a circuit board. Booya!

author: TheSteve
author_rank: Unknown
timestamp: October 06, 2018, 05:24:51 am
content: I've seen many a waveform gen that had the same looking output and it was everyone's favorite problem - bad caps. Check for ripple on the voltage rails.

author: Housedad
author_rank: Frequent Contributor
timestamp: October 09, 2018, 05:43:21 am
content: finally got time to take the lo reference box and board out. The one box houses two boards, the Low reference board and the synthesizer board. Plain 2 layer boards, mostly through hole.Under the microscope, I poured over the boards, but could not find anything mechanical wrong with them. As far as the parts themselves, I have to wait for the DE5000 to get here. (slow boat from Taiwan/Japan)I did notice one mechanical problem. The hard cable that goes from the low reference output to LO IN on the next box had the solder joint at the connector broken at both ends. It is just the solder broken, not the cable.Well, here is the tear down of the box:First pic is box in position before removalSecond and third pick shows those broken solder jointsFourth pic is the box as it came out of the unit.Boards removed.

author: Housedad
author_rank: Frequent Contributor
timestamp: October 09, 2018, 05:45:59 am
content: First pic is the two booards as they came out of the canSecond pic is the Synth boardThird pic is the Ref board. It uses a toyo tco-909 TCXOThe last pic below is just for fun.

author: Housedad
author_rank: Frequent Contributor
timestamp: October 09, 2018, 08:58:52 am
content: No ripple on the main power supply outputs at all according to the oscilloscope. The outputs are supposed to be +18. -18 and +6 volts unregulated. The 6 volt output is actually 8 volts but the 18 is at 17.945V. There are 78m05 and 78m12 regulators on the boards to provide power, and they can easily handle 2 extra volts coming in on the 6V line. Each board does it's own regulation for whatever voltage it needs and each one is in a can.

author: xrunner
author_rank: Super Contributor
timestamp: October 09, 2018, 11:52:01 am
content: Quote from: Housedad on October 09, 2018, 05:43:21 amYea you can fix that. Boards are nice and all components are labelled well. You might need to consider making up some extender cables so you can troubleshoot the units outside the enclosure with the boards operating. Should be able to find the connectors and cable to do it.

author: Housedad
author_rank: Frequent Contributor
timestamp: October 09, 2018, 05:58:55 pm
content: Quote from: xrunner on October 09, 2018, 11:52:01 amgood idea. I will look for that.

author: TimFox
author_rank: Super Contributor
timestamp: October 09, 2018, 10:37:46 pm
content: After you get the unit operating, you probably need to go through the amplitude calibration (well-described in the manual). This will require an appropriate rf voltmeter or power meter that covers the entire frequency range.

author: edpalmer42
author_rank: Super Contributor
timestamp: October 10, 2018, 03:40:16 am
content: You might get a clue where the distortion on the output is coming from with your oscilloscope. Slow down the sweep as much as necessary to get a stable envelope on the signal. Think of it as though the noise is AM modulating the carrier. Triggering on the envelope may be a challenge. The High Frequency Reject trigger setting will probably be helpful.Ed

author: Housedad
author_rank: Frequent Contributor
timestamp: October 12, 2018, 06:12:44 am
content: Two of the boards in a can (reference and plug into the motherboard with 37 pin DIN connectors. I ordered a couple of cables. That should allow me to run it out of the box, so to speak.I pulled all the units and plugged them back in. Voila', the dang thing gives a decent output wave below 500Mhz. The output of the 10mhz reference board is still crappy, but not jittery anymore.Above 500Mhz, there is now a AM modulation on the output, but no jitters.The reference board creates 10Mhz and 1 Mhz signals (for PLL Phase detection), and has another PLL on it that uses the 1 mh to make 512 Mhz for the mixer on the output board.When I tapped on the DDS board the RF output signal got brighter on the scope. Something loose and creating a resistance on the output or references? I think I need to check the motherboard out carefully.Oh, Hell. I was wondering why the card and slot position diagrams did not match up with what I was seeing. The top board in lower right can is the Reference/Lo board. And that is all they show on the diagrams. But there is another card in there. I finally got it into my head to run all over the manual and found out it is a deviation meter option. I am still a basic noob, but I hope this is a useful option.sheesh. I have been reading and studying so much to try to understand this thing, only for it to come and hit me with something else to learn.

author: Housedad
author_rank: Frequent Contributor
timestamp: October 12, 2018, 06:45:16 am
content: This project has been great for learning. Even If I never get it to work, I have learned and will learn a lot.I had never had a reason to learn about dividers, doublers, TCO's, Ocillators and PLL circuits. I have a bare inkling now that the eyes are bleeding from reading 3 books in 3 days. I'm getting a better understanding of Bypass circuits, filters, and learning more about inductors than I ever knew.This is GREAT!!!

author: Housedad
author_rank: Frequent Contributor
timestamp: October 27, 2018, 08:00:14 pm
content: Just a update.I have been waiting for my DE5000 LCR/ECR meter to come in to expedite component checking on the boards. It came in today, and I'm looking to have time to start probing on Monday.

author: xrunner
author_rank: Super Contributor
timestamp: October 27, 2018, 11:05:11 pm
content: Great! Looking forward to the PICS!

author: rf+tech
author_rank: Frequent Contributor
timestamp: October 28, 2018, 02:05:47 am
content: Housedad,FYI and anyone else following along - the Wavetek 2510 has a design "feature" where the synthesizer VCOs are susceptible to frequency modulation by external magnetic fields - as in don't stack another instrument with a mains transformer on top of or place one underneath of a 2510.The degree of FMing induced by an HP 8640B mains transformer magnetic field, underneath my example 2510, is on the order of +/- 180 Hz. Other mains powered equipment needs to be kept well away, to minimize their influence.Whether this "feature" is inherent to the 2410, I cannot say. From the photos you've posted thus far, there is little physical resemblance to the 2510 construction. When convenient, please post a few photos of the VCO board(s).My use of the word "feature" is based on acknowledgement of a former Wavetek engineer that this FMing problem was known, from the beginning.A look at the close-in phase noise of your 2410, at say 10 MHz, would also be of interest to me, if you are able to measure this once it has been sorted to your satisfaction.RF+ Tech

author: Housedad
author_rank: Frequent Contributor
timestamp: October 28, 2018, 03:13:12 am
content: I will try. I should have no problem doing what you ask.

author: tkamiya
author_rank: Super Contributor
timestamp: October 28, 2018, 11:35:26 am
content: I wonder what "XXX" on attenuator mean....? Clearly, someone has been inside before.