Hp 54501a worth grabbing?

[matt.zepess@gmail.com]

Brand new to scopes and keep seeing I need one for repairing a few laserdisc players, I also figure I can branch out with more projects and repairs. Is this a competent model? I know Dave says it’s pretty simple but this is the only one nearby that seems somewhat fair in pricing being only $45 plus shipping which I would pickup locally around a hour away. Otherwise I’m eyeing the brand new dho804 but that may take some time as I don’t wanna shell out $400+ from savings so quick. What can yall say to ease my decision? Seems like the used market is hard since most will keep it till they pass or want you to pay for their brand new model.

[colorburst]

It's fine for repetitive or slow signals, think power supplies and audio circuits. However, for anything more demanding, it has neither the sample rate (10MS/s) nor the memory depth (500 points) to be useful. It's a bit like an analog scope, except the display is not intensity-graded, so forget about XY mode or amplitude-modulated signals. It's an extremely limited instrument but a lot of times you don't need sophistication.

These are old, so expect to have to replace the Dallas block and recap the power supply. I had to do both on my 54502 years ago. The single-knob user interface is widely criticized, but I think it's quite good.

[adam4521]

The oldie to look out for, that you might be able to get for only a little bit more, is the 5462x family. Deeper memory, hi-res screen, responsive, nice feeling UI. Dave has done a video on this one, too.

[Stray Electron]

Brand new to scopes and keep seeing I need one for repairing a few laserdisc players, I also figure I can branch out with more projects and repairs. Is this a competent model? I know Dave says it’s pretty simple but this is the only one nearby that seems somewhat fair in pricing being only $45 plus shipping which I would pickup locally around a hour away. Otherwise I’m eyeing the brand new dho804 but that may take some time as I don’t wanna shell out $400+ from savings so quick. What can yall say to ease my decision? Seems like the used market is hard since most will keep it till they pass or want you to pay for their brand new model.

  I hope they don't want much for it!  Those used to sell for about $25 to $30 plus shipping on E-Greed. Make sure all of the channels work before you buy! I've had three 501s and all had at least one dead channel. Also those scopes are old enough that many of them are starting to have bad caps in the power supplies and their are no replacement PSUs or schematics available so buyer beware.  That said, I have much better scopes but I still have a 54510 sitting on my work bench and it still works great.  I never really used a 501s except for turning them on and seeing if they worked however I really like the large screen and the readouts in the 510.

   But the 54501 should be worth $45 if it works, especially if it has usable probes. If it doesn't then use that as a bargaining point.  I already had the 54510 when I bought several 54501s with the idea to use them to make curve tracers out of one of them but I never got around to it.

[dxl]

Brand new to scopes and keep seeing I need one for repairing a few laserdisc players, I also figure I can branch out with more projects and repairs. Is this a competent model? I know Dave says it’s pretty simple but this is the only one nearby that seems somewhat fair in pricing being only $45 plus shipping which I would pickup locally around a hour away. Otherwise I’m eyeing the brand new dho804 but that may take some time as I don’t wanna shell out $400+ from savings so quick. What can yall say to ease my decision? Seems like the used market is hard since most will keep it till they pass or want you to pay for their brand new model.

I had this scope about 20 years ago, and even at that point it was unusable for anything above a few KHz due to its very limited sample rate. I would look for something else.

[J-R]

Considering the hour drive, maybe just expand your budget to closer to $100 and check out something newer.  Maybe an Owon or similar USB scope?

[vk6zgo]

Brand new to scopes and keep seeing I need one for repairing a few laserdisc players, I also figure I can branch out with more projects and repairs. Is this a competent model? I know Dave says it’s pretty simple but this is the only one nearby that seems somewhat fair in pricing being only $45 plus shipping which I would pickup locally around a hour away. Otherwise I’m eyeing the brand new dho804 but that may take some time as I don’t wanna shell out $400+ from savings so quick. What can yall say to ease my decision? Seems like the used market is hard since most will keep it till they pass or want you to pay for their brand new model.

I had this scope about 20 years ago, and even at that point it was unusable for anything above a few KHz due to its very limited sample rate. I would look for something else.

That sounds like the generation of 'scopes that put a generation of Techs off DSOs.

Our "acid test" was to look at an analog video signal at field rate, which was a common test in analog days.
At around 5ms/div timebase setting the early HP & Tektronix DSOs dropped the sample rate down so far that the signal components above about 15kHz were totally lost in a blur of aliasing.

[Stray Electron]

That sounds like the generation of 'scopes that put a generation of Techs off DSOs.

Our "acid test" was to look at an analog video signal at field rate, which was a common test in analog days.
At around 5ms/div timebase setting the early HP & Tektronix DSOs dropped the sample rate down so far that the signal components above about 15kHz were totally lost in a blur of aliasing.

   The question here is whether your statement applies to the HP 54501 or not, and also what the OP intends to do with the scope. 15 MHz kHz  may be more than enough for his purposes.  I KNOW that I have used my HP 54510A up to 15 MHz and I've gotten a clean signal at that frequency.  HP says that the HP54510 is rated for 250 Mhz and they say that the HP 54501a is rated for 100 MHz so YMMV. 

   Edit: one correction, otherwise my statement stands as written.

[TomKatt]

BIG difference between 15KHz and 15MHz…

[vk6zgo]

BIG difference between 15KHz and 15MHz…

It was basically a problem with the massive reduction in sample rate at long time/div settings that made field rate video signals unwatchable with early generation DSOs.
Analog video has components out to 5MHz.
If you are only using shorter time/div settings, you can see much higher frequencies, but analog TV was a large user of 'scopes, & that was how we tested them.

[Uup]

Just to add to what others have said, if you're primarily going to work on laserdisc players then consider that you'll be needing XY mode using 1:1 probes when making adjustments to the optical block. Many DSOs don't work well in XY mode, even more recent models.

The best of the DSOs that I currently have is an MSOX4024A and, as good as the XY mode is, I find the XY mode on my old Tek CRO far better for this application. Using a DSO will require a lot of fiddling with the intensity as well as persistence settings. Although, I'm currently in the market for a 12-bit DSO, which potentially could be an improvement in regards to XY mode among other things.

Conversely, DSOs have far better triggering, making easy work out of other adjustments that you would be making. So a CRO in that respect would need to have a decent delayed sweep.
 
Also, the service manual reference images will likely line up more precisely when using a CRO, since they often are taken from one.

So if you're unsure about using an oscilloscope for anything more than working on laserdisc players, then consider picking up a cheap CRO as a starting point. You probably wouldn't lose any money if reselling it either.

[2N3055]

The best of the DSOs that I currently have is an MSOX4024A and, as good as the XY mode is, I find the XY mode on my old Tek CRO far better for this application. Using a DSO will require a lot of fiddling with the intensity as well as persistence settings. Although, I'm currently in the market for a 12-bit DSO, which potentially could be an improvement in regards to XY mode among other things.

I have MSOX3104T that is basically same scope with smaller screen. X-Y mode works but not really well.
Some new 12 bit scopes work much better. There is a topic here on EEVBLOG about this..

[tautech]

The best of the DSOs that I currently have is an MSOX4024A and, as good as the XY mode is, I find the XY mode on my old Tek CRO far better for this application. Using a DSO will require a lot of fiddling with the intensity as well as persistence settings. Although, I'm currently in the market for a 12-bit DSO, which potentially could be an improvement in regards to XY mode among other things.

I have MSOX3104T that is basically same scope with smaller screen. X-Y mode works but not really well.
Some new 12 bit scopes work much better. There is a topic here on EEVBLOG about this..

Yup.

Uup really needs to get up to speed:
https://www.eevblog.com/forum/testgear/oscilloscope-music-on-dsos-post-your-results/

[Uup]

...

Uup really needs to get up to speed:
https://www.eevblog.com/forum/testgear/oscilloscope-music-on-dsos-post-your-results/

No, I am aware of that and it's not something new either.

It seems that there is more to XY mode than what you're apparently aware of. Perhaps it is due to your lack of experience in using it in a functional way, on both a CRO and a DSO, in order to be aware of said differences.

XY mode on a DSO is akin to a viewing a colour broadcast on a black & white TV, when compared to XY mode on CRO. This has nothing to do with the processing power of a DSO or if a DSO has an LCD or a CRT.