Racal 1998 counter - anything other than buttons to check?

[timgiles]

Hi all,

Looking to get a Racal 1998 as my first decent counter for the new home lab I am putting together in a few weeks. I know what the switches are not great on the Racals, is there anything else I should be checking?   Going to fit a new OCXO in a few months. 

Thanks in advance

[wn1fju]

If it is anything like my Racal 1992 counter, and I think it is, there are two hybrid ICs on the motherboard.  The one on the right side (I think it is IC18) has a
reputation of running extremely hot, to the point that it can burn itself up.  I stuck a heatsink on my chip just to be sure.

Is there a particular reason why you are looking at Racal?  The HP 5334B (assuming you can find one with the GHz prescaler) is also a nice unit and is fairly
inexpensive on the used market.  And there are a lot of modern Chinese no-name pieces that are less than $100US, not that they are as nice as the Racal
or HP units.

[HalFET]

If it is anything like my Racal 1992 counter, and I think it is, there are two hybrid ICs on the motherboard.  The one on the right side (I think it is IC18) has a
reputation of running extremely hot, to the point that it can burn itself up.  I stuck a heatsink on my chip just to be sure.

Is there a particular reason why you are looking at Racal?  The HP 5334B (assuming you can find one with the GHz prescaler) is also a nice unit and is fairly
inexpensive on the used market.  And there are a lot of modern Chinese no-name pieces that are less than $100US, not that they are as nice as the Racal
or HP units.

If you need 1 GHz the HP 5316A with C channel option is also a good deal. They have a decent service manual and are relatively easy to find. My only note on them is that you need to slide the cover backwards when opening them up. It's rather counter-intuitive if you first try to take one apart.

[timgiles]

Thanks for the advice and info - I'll take a look.

[ct1bxt]

Hi,

I own an 1998 for several years and no issues so far.
Very good machine.
Regards
Rodrigo

[David Hess]

I got my 1992 working by just cleaning the switches.  If you are thinking of preventative maintenance, then the aluminum electrolytic capacitors should be changed.