Episode: 2148
Title: HPR2148: The DSO138 Oscilloscope Kit Part 2
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2148/hpr2148.mp3
Transcribed: 2025-10-18 14:55:34

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This is HBR episode 2,148 entitled for the SO-138 Osilov Kit Part 2.
It is hosted by Enable and is about 13 minutes long.
The summary is, in this episode Enable talks about finishing the SO-138 Osilov Kit.
This episode of HBR is brought to you by Ananasthaus.com.
Get 15% discount on all shared hosting with the offer code HBR15.
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Hello, this is Enable and I thought I'd do an HBR a little follow up to an earlier HBR I did.
As I know Ken is curious if I ever got this little scope working.
This is a follow up to the, well it was the Sainsmart DSO-138 Kit, a little scope kit.
I haven't played with it like since I did that HBR it's just sometimes I get into projects
and I'm looking at like four of them on the desk right now so they just get put aside
and then whenever I get back around to it I get back around to it so it's been months
since I played with this thing.
What brought it around to me playing around with it again was I got to thinking if you listen
to the previous episode you'll see that JYE Tech says that they are the original makers
of the board and that Sainsmart had copied them or pirated them so one day I was on Amazon
I forget what I was doing and this is how some of these projects go for me.
I'm clicking around on something and before you know it I've ordered something.
I saw the JYE DSO-138 scope kit on Amazon for $22 and I said to myself you know what I'll
just get this I'll put the original JYE Tech scope together solder that up and if I get
that working I'll be able to use that as a reference and go back and forth to the
Sainsmart one and look at voltage and you know check different points on the board and
see if I can see the discrepancy between the two as to why the Sainsmart scope is sending
the trace slamming it right to the top.
So I did build the JYE the red board it's off to my left here and then I was messing around
looking at that one to the Sainsmart board and I found a bad solder joint on J4 so jump
or four what you do is you build up this board and then you go and you test little points
you know here and there and they tell you how much voltage you should have at each point
and if all of that looks good then you short out J4 and what that does is it sends power
to the main chip because if you got something going wrong in the power splayer yet you don't
want to send nine volts to this little this little brain here the CPU inside it because
you'll just try the thing.
So way back when I soldered that up I don't know if it was a dry joint or a partial joint
or but anyways I on did it and then I wanted to check voltages again when I on did when
I on solder that J4 I noticed the like the board was damaged and like the pad had lifted
so I had too much heat there for too long way back in the past I don't know if it was making
a partial connection it must have been because the screen would go to the boot screen so
it must have been sending the three volts anyways that's either here nor there I fixed
that a little bit a little piece of wire some people call it a bodge but that's the only
way I had no pad left so they just had to put a little piece of wire in there to make
the connection between J4.
The other thing that happened with this board is if you listen to the previous episode
I mixed up what was it I think our one K and a one mega resistor let me look quick.
One K and a 10K I think that's what I had I had those mixed up on the board a one tenet
one tenet yeah one K and a 10K resistor I had fixed that way back when and then I just
never really messed around this board again so here's what it kind of turns out what I think
might have happened plus I checked other solder joints I checked over this whole thing I don't
know if when I had the one K and the 10K resistors mixed up and I sent power out to this thing
it slammed that trace right up and thought that was its original calibration you know I got the
wrong resistors in the wrong spot and that was its first boot up and it thinks okay this is the
way I'm supposed to run and bam it was slammed up to the top way back when I fixed those resistors
I haven't messed around with the board again today I fixed that J4 or I did the J4 a little better
and then I was taking the the JYE tech the red board I was taking that one screen and put it into
the black sand smart see if it was a screen problem swapping those back and forth the screen looks
good the boot sequence looks good the trace still slammed to the very top of the scope
so what I did was I just started playing with the buttons and just running them to their extremes
I was just trying to bring like the trigger level as down as low as I could the trace level down
as low as I could and I must have held like the trace level for like a good minute and it just
went down down down down down down down down down never came into the screen area but you can see
the arrow on the left hand side going down down and then it looked like it went to the top again
so it's almost like I got to like the bottom of a page of memory and then it comes back up to
the top of the screen and then I go down down down down and I click on the voltage selector and then
also I see the bottom of a square wave just up at the top of the screen just the very bottom
so I just keep holding that that button down again and slowly here comes the square wave down
into the screen so it was either through error of mine playing with these buttons way back when
when I wasn't really sure how to use it you know I just turned it on starting pressing buttons
or I had that the 1k and the 10k mixed up and it got a false calibration way back when
in any case here I have it in front of me or well I'll tell you how I have it in front of me in a
minute I had it in front of me 20 minutes ago sitting there on the bench working I was like shocked
and happy at the same time then I start thinking oh man where the heck was Ace fears he 3D printed me
a case and buttons and it's been so long I don't even know where that Ziploc bag was so I look
all over the computer room and then finally I remember I put it in a shoebox I found the shoebox
underneath the desk here got out all the parts and if you look at the pictures for this episode
you will see me slowly putting this kit into Ace fears 3D printed case
if it's quite nicely actually the screen is slightly crooked but that might just be
that could have been like how I soldered that or something but it looks pretty cool
yeah you can look at the pictures of me putting it together if you ever get this kit and then
you do this 3d print the only tricky part was getting the up down the left switch buttons
and then on the right the up down and then select I couldn't get them all in at one time because
some of them want to be on the board and some of them want to be in the case the fix I found for
that was to put some electric tape over on the sliders the selectors and then just stick them
into the case so then I could hold the case in any direction I want those buttons would stick
I put the selector buttons selector switch knobs on the switches and then I lowered the case
if that makes any sense at all lowered the case onto the board flip it over and then I noticed
on the left hand side which I wasn't aware of this when he 3d printed this there was a big space
on the left hand side well looking from the back on the left hand side and I start thinking hey that
looks big enough for a 9 volt so I went to the closet I got a 9 volt and sure enough a 9 volt fits
in there and then I start looking up at the top so what's all this business here with like a hole
and then another hole and then there's just like a little ring printed in the top and it dawns on
me this must be for a switch for it out of switch so there's a way to get this kit stick it into
this 3d print and make a fully portable unit you don't have to carry around a wall wart 9 volt
transformer with you throw a 9 volt battery in there mount the switch and that's exactly what I've
done here I'm holding in front of me you can see pictures of this you can see pictures of me putting the
the 9 volt connection on and going up to the switch which is actually a really old
switch from a Kramer focus 3000 so anybody remember Kramer focus like from the 80s the
Stratocaster knockoff this was a switch I went down on the basement and found it it was on the
pickguard and it would select I think it was uh yeah I'm trying to remember this guitar it was
ages ago back when like the original Floyd roses I'm getting a little off topic but this switch
was a selector switch so when you're down in the humbucker at the bridge position you could
coil tap it you could run it just like a regular strat you're just using one coil on the pickup
or you flip this switch and then you get the full humbucker like a Les Paul anyways I remember
this switch was down there from like 30 years ago and I go down and it's the exact switch that
fits in this little hole and I solder it all up put the 9 volt in there run the wires they even
have a little slit from where the battery compartment is over into the main board so you can run
your 9 volt leads through that little slit I put a little hot glue there to hold those down
and actually there's another related guitar thing the back went on to this thing to hold it all
together and there was no screws so I went downstairs and I got four pickguard screws so this has a
few guitar parts in it but anyways you can take a look at the pictures if you'd like it's running
I'm holding it in my hand right now I go up to the calibration the calibration loop actually hangs
out of the top of it the there's two capacitor like trim pots and you do have access to them through
the front of the case and that helps with correction if you've got a square wave and you're
overshooting or undershooting the square wave on the front of the back there's your trim pots to
calibrate your probe so to speak and the trigger light shines through the front the LED to show
if you're triggered and when you're triggering and then you have an opening in the front of the
case for reset so it's been a long project not that it took a long time but it was a long time in the
making but here it is Ken will be happy that I've brought this to a conclusion because I know he's
been wondering if this ever ever worked it did Ken and it wasn't as bad as you think get one
okay that was just a quick hpr and I just wanted to add some closure to this and show a picture of
the thing running and if you get the inspiration to try one of these kits yourself or any other
electronics kits do an episode on it and let us know how it went if anybody wants to shoot me
an email I'm in my bill at gunmonkeynet.net still kicking around on GNU social even though it seems
like it's scattered these days because some instances have stopped talking to others and some
update broke this and that and it's getting a little weird hopefully they'll resolve all that
yeah I just did it again I'm saying hopefully they I should get involved in it as well instead of
just complaining however I am and my bill at sn. gunmonkeynet.net and you can always add a comment
in the comment section of hpr if you'd like I will talk to you guys next time I break a kit
and fix it again see you later
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