Racal Dana frequency counters - Page 1
Forum section: electronics / testgear

author: Deathwish
author_rank: Unknown
timestamp: November 17, 2015, 12:06:22 pm
content: 1991 / 1992 models ,whats the general opinion on them ?.

author: Jwalling
author_rank: Unknown
timestamp: November 17, 2015, 01:11:59 pm
content: Quote from: Deathwish on November 17, 2015, 12:06:22 pmIt's been many years since I've worked on them, but many of the Racal counters including those models had problems with the front panel buttons deteriorating. I would avoid them.See:https://www.eevblog.com/forum/testgear/another-wacky-idea-to-fix-switches-on-racaldana-frequency-counters/https://www.eevblog.com/forum/reviews/racal-dana-1992-teardown/15/Jay

author: Andy Watson
author_rank: Super Contributor
timestamp: November 17, 2015, 01:31:52 pm
content: They're great ... when they work. I have two of them and often use them - no problems with the push buttons (yet!) Unless you wish to become a time-nut I would avoid the ovened variety - they take too long to warm-up; the txco is more than adequate for most jobs. Also, beware of non-working units, or units that report a "TEC" error - these counters have two custom chips and a hybrid-ceramic jobby - all of which are unobtainable.

author: Dataforensics
author_rank: Unknown
timestamp: November 17, 2015, 01:32:32 pm
content: I have experience on three of them, one bought secondhand from Ebay works fine with no button problems so far. Although I have got a set of repair switches just in case.However two that were stored unused for a few years at work ended up with every button failed when tested and were thrown out, they would not let me take them.So perhaps storage conditions/temperature.TonyTony

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: November 17, 2015, 02:58:09 pm
content: i have one, its rock solid. the button fix is easy to do if you have to do it. I have a 1992 with ovenised oscillator. its rock solid.

author: Deathwish
author_rank: Unknown
timestamp: November 17, 2015, 07:31:59 pm
content: I want a hp 53131a unit but in the meantime I got this one.http://www.ebay.co.uk/itm/262138782440?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

author: TheSteve
author_rank: Unknown
timestamp: November 17, 2015, 08:10:55 pm
content: Quote from: Deathwish on November 17, 2015, 07:31:59 pmThink big and go for the 53132A!

author: Deathwish
author_rank: Unknown
timestamp: November 17, 2015, 08:20:14 pm
content: Quote from: TheSteve on November 17, 2015, 08:10:55 pmI would have to take my socks of to count the digits !

author: Stray Electron
author_rank: Super Contributor
timestamp: November 17, 2015, 10:15:01 pm
content: I bought a 1992 from an E-scrap place a few years ago and it works like a champ! No problems at all and extremely accurate after about 20 minute warm up. (knock on wood!)

author: kwass
author_rank: Frequent Contributor
timestamp: November 17, 2015, 10:41:11 pm
content: Quote from: BloodyCactus on November 17, 2015, 02:58:09 pmI've had mine for 12 years, use it often and the buttons have been perfect. Mine has the 04E ovenized oscillator and it's been great but it does take a good 20 minutes to warm up, you'll get really inaccurate readings until it does. I use a TCXO time base counter if I need measurements in a hurry.

author: Deathwish
author_rank: Unknown
timestamp: November 18, 2015, 12:51:06 am
content: Quote from: kwass on November 17, 2015, 10:41:11 pmi also have one of those cheap 2.4ghz chinese counters but I want quality and the fact that everytime I reach up to press a button the darn things flies of the table as it is so light ....

author: lowimpedance
author_rank: Super Contributor
timestamp: November 18, 2015, 02:06:42 am
content: Quote from: Deathwish on November 17, 2015, 07:31:59 pmI would recomend checking the +/- 15V rails for excessive ripple as the 680uF electros have the cheek to dry out in these series counters.Now I have three working 1991's with no panel button issues, have replaced the afore mentioned caps though. Racal counters are generally overlooked for the more' popular named' stuff so good deals can be had. Now you have a 1.3Ghz one I'll bet the HP may not be so high on the want's list.And no fading VFD to worry about either !!.

author: Deathwish
author_rank: Unknown
timestamp: November 18, 2015, 10:30:50 am
content: Will do, as for the HP, no I still want one, whilst there may be better kit than HP etc etc there is also the availability of spares and docs for repairing such things isnt there

author: Deathwish
author_rank: Unknown
timestamp: November 20, 2015, 12:16:28 pm
content: Arrived today, looks to have about 6 or so stuck buttons so it has to come apart I think. Oh well. at least it is working.

author: Deathwish
author_rank: Unknown
timestamp: November 20, 2015, 12:25:49 pm
content: I'm actually impressed, it is currently reading 10.0000000 on a 10Mhz ocxo plugged into it

author: Jwalling
author_rank: Unknown
timestamp: November 20, 2015, 12:27:03 pm
content: Quote from: Deathwish on November 20, 2015, 12:16:28 pmIf you've got six bad, expect more to fail shortly after a bit of use.At least that was my experience.I have an HP 5386A with an external Rubidium clock. I like them as you can get 'em pretty cheap, they are easy to service as long as the 3GHz hybrid is OK, and no button problems as they use the rubber membrane type of keypad.Jay

author: Deathwish
author_rank: Unknown
timestamp: November 20, 2015, 12:35:23 pm
content: Quote from: Jwalling on November 20, 2015, 12:27:03 pmStop teasing a guy, now I am going to look for a hp unit ...just in case of course....

author: Deathwish
author_rank: Unknown
timestamp: November 20, 2015, 04:25:20 pm
content: Not sure if I am more impressed at the counter or the ocxo for being spot on.

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: November 20, 2015, 05:38:41 pm
content: its worth looking in the manual to read the crazy 'function' stuff.The only one I have memorised is the count function.Set mode to 'Total A by B', SHIFT, SF, 61, SHIFT, STORE, SF, HOLD.

author: edpalmer42
author_rank: Super Contributor
timestamp: November 20, 2015, 06:02:58 pm
content: Quote from: Jwalling on November 20, 2015, 12:27:03 pm+1 for this. If any of the switches have failed, changeallthe switches.One nice feature that is fairly well hidden is the 10 sec. gate time. It's mentioned exactlyoncein the manual. If you blink, you'll miss it. Hit the up arrow button until you've got as many digits as you can. Now hold the up arrow button in until the display goes to all zeros ( takes a second or two). Now you've got a 10 second gate time which will give you 10 MHz with a resolution of .001 Hz.Ed

author: Deathwish
author_rank: Unknown
timestamp: November 21, 2015, 04:17:30 am
content: I am a happy bunny, I have the OCXO (9462) inside ... thank you the USAF

author: MarkL
author_rank: Unknown
timestamp: November 21, 2015, 06:41:06 pm
content: Quote from: Deathwish on November 20, 2015, 12:16:28 pmI bought a Racal 1992 about 8 years ago. When I received it a bunch of buttons were also not working on the front panel. It turned out to be a cracked trace on the front panel PCB.Before you go replacing buttons, you might want to compare with the schematic to see if there's anything in common. If I recall, the cracked trace on mine was in the middle of one of the scan lines, so it didn't take out all the buttons on that scan line. Only the buttons after the crack were dead.And it's good your OCXO is exactly on. The internal OCXO is a real PITA to adjust. It's very sensitive to the slightest turn of the adjustment pot, and then it can take hours or even a day to settle again.But I'm quite pleased with the long-term stability once I got it adjusted. Just don't touch it if you don't have to.

author: edpalmer42
author_rank: Super Contributor
timestamp: November 21, 2015, 07:28:18 pm
content: Quote from: MarkL on November 21, 2015, 06:41:06 pmGood point!If the switches are actually bad, you can tell by the way they feel when you push them. If they're good, they have a bit of a 'snap' to them when you push and when you release, they jump back. If they're dead, they just go down and don't spring back at all. If any of them feel like that, they will all fail eventually.Ed

author: Deathwish
author_rank: Unknown
timestamp: November 21, 2015, 08:07:37 pm
content: No the switches are fubar, they have no roger rabbit left in them, so I aim to fix / replace them and also replace the electrolytics in the psu side etc for safety

author: timb
author_rank: Super Contributor
timestamp: November 21, 2015, 08:44:14 pm
content: Quote from: Jwalling on November 20, 2015, 12:27:03 pmI picked up a 5335A a few months back. It has the fully GPIB controlled input and OCXO options. Absolutely rock solid. I like the fact that the oven stays on even when the unit is off, so there's no real warmup period. I'd like to find a prescaler board so I can retrofit the C channel.Only downside is the thing is pretty big (standard 19" HP width, but 3U high). At least it's only half as deep as the 3456A DMM! The fan is also pretty noisy, but I dropped a Sunon MagLev in there which took care of that.Sent from my Tablet

author: enut11
author_rank: Super Contributor
timestamp: November 22, 2015, 09:19:19 am
content: Hi. Hope this is the right place to post this. I have a Racal Dana 9916 UHF frequency counter and I would like to pull it apart. It has a (heavy) cast metal chassis with plates top and bottom. The plate have 4 screws. When I remove the screws the top plate will not budge. HELP.

author: Deathwish
author_rank: Unknown
timestamp: November 22, 2015, 09:39:18 am
content: never opened one, try removing the rear panel to see why its stuck, failing that use the universal kit opener.

author: Andy Watson
author_rank: Super Contributor
timestamp: November 22, 2015, 12:00:11 pm
content: Quote from: enut11 on November 22, 2015, 09:19:19 amYou're only half-way there. The manual says to remove the rubber plugs and slacken some more screw: section 5.1.http://www.ko4bb.com/manuals/download.php?file=Racal/Racal_Dana_9916_Frequency_Counter_Service_Manual.pdf

author: enut11
author_rank: Super Contributor
timestamp: November 22, 2015, 11:06:22 pm
content: Hi Andy. Thanks heaps for the 9916 workshop manual. This will be invaluable as I do not have a user manual either. I was able to dismantle the unit and had a good look inside. Fortunately I did not need deathwish's special tool!As I have just purchased the unit I am trying to determine if the internal frequency standard is OK.I do not have a specific use for ultra accuracy at present. I just like fiddling with old stuff and getting the best out of it.enut11

author: KJDS
author_rank: Super Contributor
timestamp: November 22, 2015, 11:16:26 pm
content: Quote from: enut11 on November 22, 2015, 11:06:22 pmI've just bought a big box of Racal 5MHz frequency standards of varying sorts. Haven't collected them yet and it'll take a few days to test them, but shout if you need one.

author: enut11
author_rank: Super Contributor
timestamp: November 23, 2015, 12:04:59 am
content: Thanks kjds. Do you know if the Racal 5MHz standards are good wrt stability and drift? This is a new subject matter for me and I am trying to understand what is important and why. Also, the 9916 has provision at the rear for an external standard input so am looking at what's out there. All low key at present as I read and learn more.enut11

author: KJDS
author_rank: Super Contributor
timestamp: November 23, 2015, 08:29:12 am
content: Those big Racal standards are great, there are some details in the link belowhttp://www.ko4bb.com/manuals/2.121.199.214/Racal_9400_series_OCXOs_annotated.pdfbut if anyone else has any info on them I'd appreciate it.

author: Deathwish
author_rank: Unknown
timestamp: November 23, 2015, 09:27:44 am
content: Quote from: enut11 on November 22, 2015, 11:06:22 pmSigh, me too but it just keeps pointing at the groundKev, if you have a 9462 unit in that lot let me know will you, i would like a spare

author: enut11
author_rank: Super Contributor
timestamp: November 23, 2015, 09:36:52 am
content: Quote from: KJDS on November 23, 2015, 08:29:12 am......................................................................Hi kjds, the Racal OCXO link did not work...

author: Deathwish
author_rank: Unknown
timestamp: November 23, 2015, 09:47:40 am
content: Quote from: enut11 on November 23, 2015, 09:36:52 amhttp://www.ko4bb.com/manuals/86.153.249.8/Racal_9400_series_OCXOs_annotated.pdf

author: Majkic
author_rank: Newbie
timestamp: January 02, 2025, 08:55:34 pm
content: I'm very late to the conversation here, but the reason for my post is that over the Christmas period (2024) I bought a Racal Dana 1991 counter from an eBay seller. This arrived in good cosmetic condition and superficially appeared to work. However, I soon realised that a significant number of the front-panel buttons were inoperative, and of course began looking on the Web to see if it was a commonplace problem - which clearly it is!Having learned (and confirmed for myself the hard way, after wasting a couple of hours on the Web!) that identical replacements are simply not available, I was about to embark on the course proposed by Ian Scott Johnston in the excellent YouTube video that's referenced earlier in this thread. That is, you buy some replacement switches that will fit the PCB and then "fettle" (mechanically modify and glue in place) the Racal push-buttons to fit the round actuator stems that appear on switches that are available today.However, Ian's video also mentions (as do others) that his switches were mechanically as well as electrically dead, whereas all mine appeared to work perfectly from a mechanical point of view -- all of them sprung back nicely when I pressed them. I also then chanced upon a posting by a German gent called Ulrich Bangert, which he'd written in 2012 on Febo.com in a group called "time-nuts" (accessible as I write athttps://www.febo.com/pipermail/time-nuts/2012-April/066433.html). Ulrich is sadly no longer with us, but his web site is presently being kept alive by a friend (or maybe family member) called Hartmut Päsler. Ulrich's web site (http://www.ulrich-bangert.de/) doesn't have any index links to Racal counter information, but the photo he references in the "time-nuts" thread is still there. I hope nobody will mind my re-posting Ulrich's comments here so that - along with my own subsequent findings - they can be of use to others with this same switch issue. Ulrich writes as follows:I know I am not the only one in this group to have difficulties with "weak" tactile switches on Racal-Dana's 1991/2/6 range of counters. The other day I talked to the chief technician at Rosenkranz-Elektronik which is one of the biggest surplus suppliers in Germany. He knew the problem very well and his claim was that an exact replacement for the original Toko switches is no more produced anywhere in the world. Which may be an explanation why none of us managed to find an exact replacement. His second claim was that the switches can be repaired: After removing the cap gently, grip the moving part with a pair of pliers and twist it a little bit while pulling it out a bit at the same time. In this way the moving part can be removed without destruction of the switch. Then you find the source of the problem inside: The weak and mostly destroyed rubber part inside. Replace it with the rubber part of a switch which has NEARLY the same dimensions. He told me that he had done such a repair for a number of times. Unfortunately he had no reference for the switches that he had used as the source for the replacement rubber. I am aware that this is only half of the solution of the problem but I checked his suggestion with a original switch that I had laying around as a replacement and found that his description worked for me. I made a photograph of the switch to be found here:http://www.ulrich-bangert.de/Racal.JPG(or see attachment here)In the photo, the central grey rubber projection forms a mechanical "return" spring, and is intended to hold the switch open when the button isn't pressed. The black circumferential portion of the rubber piece is carbon-loaded rubber. This is (or is supposed to be) electrically conductive, and it bridges the two gold contacts with a relatively low resistance path (a few hundred ohms, but not a hard short circuit as it's not a metal bridge) whenever the switch is pressed. Clearly in some switches (like mine) the surface of the conductive rubber degrades with time, so that the closed contact resistance increases to the point where the switch no longer functions electrically-speaking.As Ulrich says, replacing the rubber part is only half a solution in itself, unless you really can find some switches with similar, mechanically-compatible, rubber innards that can be substituted. However, it then occurred to me that as all my switches were apparently mechanically OK, maybe there was some scope for simply cleaning them inside, rather than having to replace them all. A quick investigation with a multimeter confirmed that the faulty switches had a very high "on" resistance of typically tens or even hundreds of kilo-ohms, whereas the ones that work were much lower, typically a few hundred ohms. So I followed Ulrich's information and was easily able to dismantle one of the defective switches.Some words of immediate caution if you decide to do the same:(1) The rubber membrane is tiny (maybe 2.5mm in diameter) and it isn't strongly captive inside the nylon actuator. So it's quite easy for it to fall off the actuator, or out of the switch body; and if your workshop floor is anything like mine, it'll be years before you ever find it again - even assuming the vacuum cleaner doesn't get it first! So be very careful not to allow it to fall; work on a clean bench with plenty of space around the job so that if the rubber bit does fall out, you don't lose it.(2) Although only a very little movement is required, it's necessary to grip the nylon actuator "stem" quite firmly, and it's possible to crush the cross-shaped moulding onto which the button fits. I learned this the hard way, fortunately not causing so much damage that the button couldn't be re-fitted, but it was a close thing, and very annoying to have caused damage this way. Best to grip the nylon part close to the switch body, where it's cylindrical or fully square (I forget which) and don't squeeze too hard, but also don't let the pliers slip onto the cross-shaped section!After dismantling the switch, carefully replace the rubber part in the nylon actuator by hand - again be extremely careful not to drop it, or allow its elasticity to "ping" the part across the room! Once properly re-seated, the rubber part should - if not badly degraded, which none of mine were - sit snugly in the end of the nylon, held in place by its own stiffness. Then, get a small piece of clean cotton cloth (I used some lint-free wiper squares) and dampen it with isopropyl alcohol (isopropanol), and place the wet cloth on a clean flat area of the bench (I did this on a clean antistatic mat). Hold the switch actuator and press the rubber end gently but firmly against the damp wiper, so that the black conductive rubber portion is in contact with the alcohol-dampened cloth. Rub the piece in a circular motion, then back and forth in all directions so that the black part of the switch rubber is gently polished and cleaned. You'll see the wiper turn black as a very small amount of surface rubber is removed. Don't over-do it - a few strokes in each direction is enough. I suggest then drying off the rubber by gently wiping it on separate clean, dry square of cloth, then re-assemble the switch and check its on-resistance again.I found that in all cases I could restore the switch on-resistance to a few hundred ohms; I've no idea what the data-sheet figure would have been but this seems more than low enough to ensure reliable operation in the Racal counter. I cleaned all thirty-odd switches (even though not all had failed to work) whilst I had the thing in bits, and although it was a bit of a nerve-racking exercise, it only took a couple of hours, and it was certainly by far easier, quicker and less invasive than replacing all the switches with the associated tasks of de-soldering, removal (or chopping up) of the central driver IC socket, drilling out the button caps and then gluing them back in place.Of course, none of this helps if (as In Ian Scott Johnston's case) the rubber membranes inside your switches have degraded so badly they no longer mechanically function. But if (like me) you have mechanically sound switches that just don't work, then this may well save you a lot of time and trouble. My thanks and acknowledgements to the late Ulrich for his post, and to his buddy Hartmut for keeping the web site and its associated switch photo on line. My Racal 1991 is now working beautifully, and I'd never have sorted the problem without this invaluable information.