Drool. But I'm good. ![Grin ;D](https://www.eevblog.com/forum/Smileys/default/xgrin.gif.pagespeed.ic.QVVz6XIT20.png)
![](https://imagizer.imageshack.com/v2/800x600q90/922/o1P4vq.jpg)
The 20MHz ancestor to that 5248L just arrived here yesterday
, cost me way too much, but they were already extinct over here in the UK (no thanks to that timepiece butcherer from Stafford). ![Cry :'(](https://www.eevblog.com/forum/Smileys/default/xcry.gif.pagespeed.ic.tehjCtKixU.png)
David
Here is the early HP 5243L counter that arrived on Friday from the US, the seller did an excellent job of packing it for international shipping (I didn't have to ask either)
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/xsmiley.gif.pagespeed.ic.R8GFI-pF6f.png)
.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1086644;image)
The 20MHz 5243L was first available in the 1962 catalog and also in the 1963 & 63/64 short form catalogs, before being replaced by the 50MHz 5245L after mid 1963.
It has option H16 which adds the time base multiplier switch, to give a 100 second gate time when set to X10 (with the time base switch set to 10s).
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1086648;image)
Option H18 gives both a 100 second & 1000 second gate time for the HP 5245 series according to a service manual I acquired with another counter some time ago.
Note: both options H16 & H18 only add the multiplier switch & extra divider circuits, neither change the decimal point, you have to multiply the readout by 10 or 100.The 5243L is mostly working
![Grin ;D](https://www.eevblog.com/forum/Smileys/default/xgrin.gif.pagespeed.ic.QVVz6XIT20.png)
, the HP 209A oscillator I repaired earlier this year was used for testing, just a few issues with the display circuits that need repair, the LSD isn't working well and a 6 is absent from another display circuit.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1086652;image)
The serial prefix/number is 328-01183 & there is no sticker indicating if the later plug-ins can be used, but I do have the service note for the modification, plus the 5245L spares unit (with all the plug-in circuit boards missing) that I got from a member of the UK vintage radio forum with that big pile of test gear in August, that must have the wiring needed for the mod.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1086656;image)
Will break the very old cal seals & have a look inside another day.
David