HP 53310A signal source / demo box - Page 1
Forum section: electronics / testgear

author: artag
author_rank: Super Contributor
timestamp: June 06, 2023, 03:26:24 pm
content: What's up with this 53310A demo box ?https://www.ebay.co.uk/itm/304083321442It seems to have some non-standard modulation options (those last two are usually data-to-clock jitter and pulse width modulation). Not sure if that was a factory or user mod, but it also implies the outputs could be changed somehow. Or maybe that's what they really are and they just happen to be useful for generating the generic displays.What's in the box, anyway ? I don't have one, but perhaps someone here does. Would you do a teardown ? It's hard to find any documentation on it, even a part number - though obviously the outputs are documented in the 53310A quick start guide.

author: artag
author_rank: Super Contributor
timestamp: July 20, 2023, 01:12:35 pm
content: I finally got one of these at a sensible price. Apparently I wasn't the only person looking for one as the ebay seller had 4 and they've already all sold.It seems the answer to what's inside is that it's an eprom-based digital synthesizer with just 3 ls161 counters to run it, no microprocessor, and a handful of analog parts for filtering etc.If there's interest I may do a teardown but the eprom is soldered in so it may be difficult to read it's contents.

author: Kean
author_rank: Unknown
timestamp: July 24, 2023, 03:21:27 am
content: OK, so just a simple 2 channel pre-programmed AWG.The "signal select" slide switch would set the upper bits of the address bus (either direct to EEPROM or loaded into the upper ls161 counter), and the counters get clocked by the reference input.Different EPROMs would allow synthesis of different demo waveforms, which explains the dodgy looking labeling.Out of interest, how is the box powered?Maybe you could capture the analog output waveforms for "posterity".

author: artag
author_rank: Super Contributor
timestamp: July 24, 2023, 10:39:55 am
content: Yes, pretty much.Note that the one I just bought isn't the one I first asked about - it has the conventional HP labelling on the switch.I'll look at capturing the waveform but at first glance it produces a rather jittery signal on the scope as you'd expect from a phase modulated source. A useful capture will depend on how long the repeat cycle is (though triggering on the eprom address bits might help).It's only one channel of AWG. The centre BNC has a fixed 1.25MHz square wave from a 74161 - A2 of the eprom.The box runs from a PP3 / MN1604 9V battery. It's clocked from an external 10MHz source (nominally the 53310A ref output) .3 x 74act161 4 bit sync counter1 x am27c128 16k eprom1 x 74actq377 octal D flipflop (just latches data for DAC, doesn't seem to feed back to eprom)1 x tlc7524 8 bit dac1 x ad843 fast op-amp1 x max635 inverting switching regulator ( for -5v )2 x 75L05 linear regulator (one for analog, one for digital)Something unfamiliar to me are those yellow things. They're like 3-legged tants, and are marked 106k. I thought at first they were ceramic resonators but I can't imagine they'd need 7 of them nor that the voltage regulators would have them.TIL about 3-terminal capacitors.

author: Kean
author_rank: Unknown
timestamp: July 25, 2023, 12:36:42 pm
content: Quote from: artag on July 24, 2023, 10:39:55 amThere are actually two types of 3-terminal capacitors (that I have come across).These ones are higher value tantalum (eg 1uF or more) and usually have the two outer legs internally connected to the negative side.The other type are lower value ceramic feed-through capacitors (eg 1nF or less), with the centre leg to GND and used for EMI suppression.Both types can be inserted either way, so would speed up manual assembly. They are almost certainly no longer manufactured.