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Old 26th Jul 2021, 10:16 pm   #67
factory
Octode
 
Join Date: Jul 2009
Location: Cheshire, UK.
Posts: 1,706
Default Re: HP 180A Oscilloscope.

Quote:
Originally Posted by Radio Wrangler View Post
THe 1820 was the very basic entry-level timebase. It's far out-numbered by the 1821 dual timebase, so model specific spares will be a lot harder to find. The C suffix means it's one of the last updates.

HP did some dual timebases that were rather covert to not intimidate people, they had controls putting it over as an 'expansion' function.

The need for a simpler timebase was limited because any firm prepared to stump up the prices of a 180 system was going to want to go all the way.

David
I can't remember buying this, but I found I have a 1824A timebase with the expansion function.
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It triggers fine, but the 1801A that came with it only works on channel B.
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Last night I had a look through the manuals for the 1820C & 1824A on the Keysight website and was surprised to see they share a number of boards (apart from the main board & the extra board for the expander switch). The IC's used are obsolete, but still plenty of old stock available.
They are 1826-0086 = UA776HC ? (Op-Amp), 1820-0806 MC10109P (strange ECL OR/NOR gate) and 1858-0004 = CA3049 (transistor array).

As for the 1820C, I can't understand why they didn't give it a new model number, as it is quite different in design to the 1820A, which used all discrete components including the tunnel diodes and the front panel layout is different.
Can't comment on the 1820B, as I can't find any pictures showing the circuit boards.

David

P.S. A big thank you to Radio Wrangler for sending me the CRT bezel.
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