Racal-Dana 1999 Teardown, Repair and Calibration

I have been using this Racal-Dana 1999 counter for a long time and in the last few months it started to suffer from an intermittent fault where it would appear to freeze and stop responding. Banging the unit on the side with the palm of my hand would get it going again, and when doing this it would often restart as if its been powered on. In addition to this fault, the counter suffers from an altogether common problem with the buttons on the front which loose any tactile feel to them and become difficult to actuate – this is a common problem on these counters and thats down to the poorly designed switches Racal used for its frequency counter range.

I identify the fault and fix the problem and I replace all the buttons with ones that work and end up with a fully restored frequency counter once again.

I have made the manual including schematics available in the attachments section of this article for your convenience

See you next time….

This content is published under the Attribution-Noncommercial-Share Alike 3.0 Unported license.


File Description File size Downloads
pdf Racal 1998/1999 Frequency Counter Maintenance Manual 3 MB 5326


  1. Excellent video once again Gerry. And well titled also so someone reaching out to fix theirs should easily find it.

    Good news on the upcoming Agilent options boards as well, I look forward to both.

  2. You video regarding this particular repair provides one with useful techniques for their own repairs. The calibration using the scope is simple but elegant. A very good video. Thanks

    1. Hi Dan, glad you found it useful. Not doing anything special with the scope, its been done many times before but I am glad to be able to spread the word – its THE best way of tuning one oscillator to another, nothing else gives you the same visual cue. Gerry

  3. Another great video Gerry….count me in as interested in an OCXO board for the 5131A; although I mostly run all the test gear boxes from my 10MHz standard it would be nice to have a portable capability with better specs than the low-end reference…brings up a good question – with the OCXO board in there will we need to leave the fan run continuously to keep the box from overheating? I leave the counter unpowered now to avoid the continuous fan noise since when it’s turned on it has 10MHz immediately available from the workbench standard (considering your hard wire switch mod as well).


    1. Hi Dino, thanks for the comments. My OCXO seems to be up to working temperature in about 15 minutes which is pretty good, leave it on for an hour to be sure. That being said the RFS is up and running in a couple of minutes and the fan is dead quiet. The power switch nmod is well worth the effort IMHO, I hate the fan noise when I don’t need it. Gerry

  4. Yes this is the type of video I like and need, I learned lots from this well done Gerry, you can have Friday off 🙂

  5. Gerry, terrific video. Many folks have (and love) their 1992 model which has the same push button issues. Can you post information about the switches you used (from Ebay)? Also, I would love to see a new video with an update to the oscillator. Keep up the good work. Jim Robbins, N1JR

    1. Hi Jim, thanks for the feedback. I bought the buttons on e-bay. They are not perfect by any stretch of the imagination and the mod is quite a pain to do and irreversible because of the button cutting and gluing that needs to go on – but they are a hell of a lot better than the original crappy broken buttons thats for sure. I can’t remember the exact source but the buttons you want are 6mm x 6mm x 10mm shaft length with two pins (not four as they often are). I bought 100 of them for a few dollars from what I can remember. I actually got the wrong ones, I got 7mm shaft length so there was more faffing around than there should have been, the 100mm shaft length buttons will be the best fit.

      A few people have mentioned doing an updated oscillator mod on the Racal – it could certainly do with it, the default oscillator is very stable once it warms up but its very hard to trim with any degree of accuracy. I do have a reasonably nice lowish power OCXO that I could graft in as a quick and dirty tea-break mod – i will try and do that soon as people are interested.


  6. Hi Gerry,
    Nice repair video. Are those large 4 pin electrolytic caps from Philips in the power supply? They look like the type you find in old Philips PM type oscilloscopes. Always wondered if they can be replaced by regular ones. Do you know?

    1. Hi Harry,

      I have not looked specifically but yes they are in the PSU. No reason why they could not be replaced, its just physical constraints that might prevent. Thanks for the feedback.


      1. Was surprised to see them so soon again when you opened the box 🙂 Luckily only the 2 pin ones needed replacement in my 80’s scope power supply. Didn’t find much info on them and wondered why they were used. Thanks Harry

  7. Hello Gerry,
    Thanks for the file to the service manual.
    I have a Racal – Dana 1998 and I am very pleased with it.
    If I had 10 MHz sinewave FE-5680A Rubidium Oscillator to calibrate it’d be even more pleased.

    1. Hi Mitko, you are very welcome, glad it was of some use. Yes its nice to have something like am FE-5680A to calibrate against, my little project using one of those has worked out really well for the most part, although oddly, it could do with the addition of an OCXO to iron out the timing correction glitches that emanate from the FE-5860A…but thats another video lol Gerry

  8. Just picked up a 1998 of ebay and it’s got the same dead buttons, thankfully for this great vid I know how to fix it. The only concerning thing with mine is that custom 40 pin ceramic chip with the gold color cap is absolutely blazing hot, after it’s been on for 5-10 minutes I can barely keep my finger on that chip more than a few seconds.

    Was wondering if you noticed that with yours? It doesn’t seem right that it should be running so hot but if it is the case then I will probably look at trying to heatsink it somehow.

    1. Paul,
      I don’t recall it running that hot although it might – its at least ceramic 🙂 So long as it working I think you are ok but gluing a decent heatsink to it will certainly do no harm. However, I am not sure how much good it will do either as there is no forced air movement in the enclosure so once the heatsink is up to temperature it won’t be doing its job any more. The only option would be some kind of mechanical attachment of the heatsink to the side of the case to dissipate the heat away form the chip.

  9. I have Racal Dana 1999. I am getting Error 50 message. I have done every thing to get rid of it but nothing worked for me

    1. Hi Muhammad,

      I am afraid I don’t know much about these counters, I am not familiar with what error 50 means. The manual says “Incorrect result when in check mode” which I presume means some form of self-test has failed.


    1. Hi,
      I think you need to get an oscilloscope out and have a look at the oscillator output. These counters use the reference clock as the clock for the microprocessor. Those symptoms would suggest there is no clock, so could be a failed oscillator

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