HP 54540C Dumpster Scope - Page 1
Forum section: electronics / testgear

author: G0HZU
author_rank: Super Contributor
timestamp: December 16, 2015, 05:12:33 pm
content: I salvaged a pile of scrap test gear at work today and in amongst the scopes was one of these old DSOs from HP:http://www.keysight.com/en/pd-1000001424%3Aepsg%3Apro-pn-54540C/4-channel-500-msa-color-digitizing-oscilloscope-obsolete?cc=US&lc=engIt seems to work OK and I wondered if anyone has any experience of these old scopes. I'm guessing that it must be nearly 20 years old. It has been sat unused for many years in an old storeroom along with a load of other obsolete test gear. The display seems a bit gloomy and my initial fumblings with it have failed to find a brightness control in the menus.It's likely to have seen a lot of use so maybe the backlight is old/fading. Is there an adjuster inside for brightness or contrast? It's still perfectly useable but it does look like it needs a tweak to the brightness or contrast.I know that the 2GSa/s sample rate and 500MHz BW goes down as I enable 2 or more channels but are there any other gotchas with this old scope? I might keep it as it has 4 channels and it has a floppy for storing screenshots and (presumably) full control via GPIB. So it might come in handy from time to time.

author: free_electron
author_rank: Super Contributor
timestamp: December 16, 2015, 05:18:39 pm
content: they are not bad machines.but, BEFORE you get all worked up and excited.pull out the power supply and replace ALL capacitors. these power supplies are notorious for cat-wee smell after which the scope goes poof and you can throw it away....especially when it has sat for such a long time.and also check the schaffner power input. it may need a replacement before it goes kaboom too...

author: KJDS
author_rank: Super Contributor
timestamp: December 16, 2015, 05:28:28 pm
content: on the black and white models, the brightness adjustment was a screw round the back**this is not to be confused with young fumblings behind the bike sheds

author: G0HZU
author_rank: Super Contributor
timestamp: December 16, 2015, 05:34:29 pm
content: OK thanks for the adviceHere's an image of it. The good news is that the display seems to get brighter as it is left on. It's been on for maybe 10 minutes now. I don't get excited about scopes so I'm not sure if I'm going to keep this one or not. I'm not too keen about recapping all the caps in the PSUAre there lots of them?

author: G0HZU
author_rank: Super Contributor
timestamp: December 16, 2015, 05:36:24 pm
content: I've had a look on the back panel but I can't see an adjustment screw. I think it just needs a bit more contrast but maybe these old colour LCD displays are naturally a bit gloomy.

author: wblock
author_rank: Regular Contributor
timestamp: December 16, 2015, 06:08:46 pm
content: Don't these machines run a (very old) version of Windows? Has anyone ever replaced the monitor with an LCD?

author: G0HZU
author_rank: Super Contributor
timestamp: December 16, 2015, 06:19:47 pm
content: It doesn't run Windows but this C version does already have a colour (VGA ) LCD display as standard. The mono version uses a CRT but this one has a flat panel LCD display. I've also raised the viewing angle up a bit and this has improved the contrast a lot. So the display looks OK now. Much better than my earlier image above but it does have a fairly limited viewing angle before the screen loses contrast.

author: tggzzz
author_rank: Super Contributor
timestamp: December 16, 2015, 06:39:52 pm
content: Quote from: G0HZU on December 16, 2015, 05:34:29 pmClearly your best course of action is get someone to take it off your hands, gratis. When do you want me to come? Looks like about only an hours travel each way

author: wblock
author_rank: Regular Contributor
timestamp: December 16, 2015, 06:43:34 pm
content: Too bad we aren't in the same country, that seems like a worthwhile DSO to recap, even if it does only have 32K of sample memory.If you open it, photos would be good.

author: G0HZU
author_rank: Super Contributor
timestamp: December 16, 2015, 07:03:48 pm
content: I'll have a go at opening it some time over xmas and look for any leaking caps. If the caps look OK inside I think I'll keep itI've taken a look inside the big probe wallet on top and there were no probes there but I did find the original firmware (3.5" FDD) disk inside the original EULA envelope from HP. This was dated Jan 1996.The firmware disk only has two files on it (ROM and SYSTEM) and it covers lots of models including the 54542C. It would be nice if the 40C could be hacked to become a 42C but I'm guessing the hardware will be different inside?Also this scope boots really fast. Just a few seconds. There is a fair bit of fan noise but not as bad as I feared for an old 2GSa/s 500MHz scope.

author: free_electron
author_rank: Super Contributor
timestamp: December 16, 2015, 08:00:24 pm
content: motorola 68k . same system architecture as their logic analysers (16500)