A few years ago, my Owon PDS 5022S oscilloscope failed with a strange
looking display. See photo at:
<https://photos.app.goo.gl/rYGeaGygSMXHtMCb8>
From what is visible on the display, everything seems to be working
except for the strange display. Whatever is wrong is probably in
either the color LCD display or the circuitry that drives the display.
Does anyone have a clue what might have failed? Mostly, I'm trying to
save time fixing it. (I haven't torn it apart yet).

User manual (no schematic or block diagram):
<https://www.saelig.com/downloads/pds5022s.pdf>
Specs:
<https://www.batronix.com/shop/oscilloscopes/digital-oscilloscope-pds5022s.html>

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

On Wed, 14 Aug 2024 14:26:48 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:

Eeuuwww. Pure guess ....
One of the voltages on the display tube itself has gone off. Right orff.
Could be that a cap has broken down.
But in a very worst case, a weld inside the display tube has opened up.

On Wed, 14 Aug 2024 14:26:48 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>A few years ago, my Owon PDS 5022S oscilloscope failed with a strange
>looking display. See photo at:
><https://photos.app.goo.gl/rYGeaGygSMXHtMCb8>
>From what is visible on the display, everything seems to be working
>except for the strange display. Whatever is wrong is probably in
>either the color LCD display or the circuitry that drives the display.
>Does anyone have a clue what might have failed? Mostly, I'm trying to
>save time fixing it. (I haven't torn it apart yet).
>
>User manual (no schematic or block diagram):
><https://www.saelig.com/downloads/pds5022s.pdf>
>Specs:
><https://www.batronix.com/shop/oscilloscopes/digital-oscilloscope-pds5022s.html>

Don't be afraid to open it up, just be carefull.

Could be something simple. I had a TDS210 that was shipped with a
reversed and burst electrolytic. Worked fine for a while before
requiring a simple fix. Display showed first symptoms.

The bloom around the LCD display looks physical, to me.

As a battery-powered device, it'll have it's uses.

I have a few Owon SDS8202s that are eating their batteries
regularly. I've introduced balancing, internally, but the
charging circuit possibly overvolts the battery chemistry.
Simple is good, but ignoring the float upper limit is just
stupid.

RL

On Thu, 15 Aug 2024 09:16:57 +1000, Black Iccy
<Daedelus@whereamIinvalid.com> wrote:

>On Wed, 14 Aug 2024 14:26:48 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:
>
>Eeuuwww. Pure guess ....
>One of the voltages on the display tube itself has gone off. Right orff.

Ummm... it's not a CRT. It's a color LCD 640x480 panel.

>Could be that a cap has broken down.

I haven't torn the DSO apart yet. The display is not packaged to make
disassembly or inspection easy. I've seen literally hundreds of
computer LCD panels but never one that looks like the photo.

>But in a very worst case, a weld inside the display tube has opened up.

It's not a CRT.

Thanks for trying.

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

On Wed, 14 Aug 2024 20:55:27 -0400, legg <legg@nospam.magma.ca> wrote:

>On Wed, 14 Aug 2024 14:26:48 -0700, Jeff Liebermann <jeffl@cruzio.com>
>wrote:
>
>>A few years ago, my Owon PDS 5022S oscilloscope failed with a strange
>>looking display. See photo at:
>><https://photos.app.goo.gl/rYGeaGygSMXHtMCb8>
>>From what is visible on the display, everything seems to be working
>>except for the strange display. Whatever is wrong is probably in
>>either the color LCD display or the circuitry that drives the display.
>>Does anyone have a clue what might have failed? Mostly, I'm trying to
>>save time fixing it. (I haven't torn it apart yet).
>>
>>User manual (no schematic or block diagram):
>><https://www.saelig.com/downloads/pds5022s.pdf>
>>Specs:
>><https://www.batronix.com/shop/oscilloscopes/digital-oscilloscope-pds5022s.html>
>
>Don't be afraid to open it up, just be carefull.

I'm fearless and moderately careful. My problem is that I'm in the
process of purging all the old junk from my house. When I retired and
closed the office, I had to drag everything from the office to the
house. The house has been a mess since Sept 2020. I have quite a bit
of equipment that I know can be fixed if I had the time and bench
space. For this DSO, the problem is both lack of time and lack of
bench space. I can't just tear it apart and leave it. The reason I
asked for clues is to save time monopolizing the workbench and
troubleshooting the problem. In this case, I've seen literally
hundreds of failed LCD computers displays, but none have ever looked
like the photograph.

>Could be something simple. I had a TDS210 that was shipped with a
> reversed and burst electrolytic. Worked fine for a while before
>requiring a simple fix. Display showed first symptoms.

The DSO is old enough that a bad electrolytic is a likely problem. I
couldn't find any information that would help establish the age. So,
I measure a few voltages. If that fails, I find where my ESR tester
is hiding and check every electrolytic.

>The bloom around the LCD display looks physical, to me.

There's no evidence of a crack in the display.

>As a battery-powered device, it'll have it's uses.

It has an AC charger and power supply built in. The battery pack is
proprietary. I plan to use the AC PS for testing and to build a
suitable battery pack when it's fixed.

Incidentally, I used it for about a year before it suddenly quit. It's
only 20MHz bandwidth, but that was good enough for audio.

>I have a few Owon SDS8202s that are eating their batteries
>regularly. I've introduced balancing, internally, but the
>charging circuit possibly overvolts the battery chemistry.
>Simple is good, but ignoring the float upper limit is just
>stupid.

That's a much later 200MHz DSO:
<https://www.saelig.com/product/PSBEB100007.htm>
The previous owner of my PDS5022s mentioned that overcharging the
battery was also a problem. If it used LiIon and there was no BMS, I
would not expect the battery to last very long. I have a few devices
have no battery protection or balancing. When possible, I add the
necessary circuitry. More commonly, I just bring out all the internal
battery connections to a balancing connector and use a radio-control
style external charger. I have one of these which will charge almost
any battery:
<https://hobbyking.com/en_us/skyrc-imax-b6-v2-60w-6a-1-6s-dc-charger-discharger.html>

Thanks for trying. I'll try to remember to post something when it's
fixed, sold as-is or recycled.
--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

On Thu, 15 Aug 2024 13:18:31 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:

>Ummm... it's not a CRT. It's a color LCD 640x480 panel.

Yeah.
The sunlight shone just after I clicked "send"
Serves me right for " living in the past" -)

On Wed, 14 Aug 2024 14:26:48 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>A few years ago, my Owon PDS 5022S oscilloscope failed with a strange
>looking display. See photo at:
><https://photos.app.goo.gl/rYGeaGygSMXHtMCb8>
>From what is visible on the display, everything seems to be working
>except for the strange display. Whatever is wrong is probably in
>either the color LCD display or the circuitry that drives the display.
>Does anyone have a clue what might have failed? Mostly, I'm trying to
>save time fixing it. (I haven't torn it apart yet).
>
>User manual (no schematic or block diagram):
><https://www.saelig.com/downloads/pds5022s.pdf>
>Specs:
><https://www.batronix.com/shop/oscilloscopes/digital-oscilloscope-pds5022s.html>

Video of a Digimess DS25 DSO, which is similar to my Owon PDS5022s:
<https://www.youtube.com/watch?v=yfjh0KDEaTY>
The plastic case, front panel, and oscilloscope section are identical.
However, the LCD panel, power supply and backlighting inverter are
very different.

More videos:
This PDS5022S video is 14 year old with upgraded firmware:
<https://www.youtube.com/watch?v=JQtvW1wpl6w>

More of the same:
<https://www.youtube.com/shorts/6OCnuXpM2mY> (same problem as mine)
<https://www.youtube.com/watch?v=M0galCMhm7U>
<https://www.youtube.com/watch?v=nydo6xsLY7g>
<https://www.youtube.com/watch?v=hzZpE9yrMKA>
<https://www.youtube.com/watch?v=UInlOkFDf24> (shows defective LCD)
<https://www.youtube.com/watch?v=X1OTPt7_1Z8>
<https://www.youtube.com/watch?v=1sUGiwaEjq8> (shows defective LCD)
<https://www.youtube.com/watch?v=xHaapgrXxYI>
<https://www.youtube.com/watch?v=escwIX0vY64> (looks similar to mine)
<https://www.youtube.com/watch?v=EQXzP6sazaA>
<https://www.youtube.com/watch?v=MNzaAPetnVw>
<https://www.youtube.com/watch?v=K3mITKGuAW4>
<https://www.youtube.com/watch?v=bjRQP8mDCV0>

Some photos of the internals:
<https://photos.app.goo.gl/ZgCRUB4SChDYRrRy6>
When I removed the cover, I was immediately hit with the distinctive
smell of burned resistor. I tried to find the source with my nose,
but failed. When I "fire" it up again, I'll do some more fault
"sniffing".

Visual inspection didn't find anything that looked like a problem. I
tested all the electrolytics with an ESR tester. I did another visual
inspection with a microscope:
<https://www.learnbydestroying.com/jeffl/pics/microscopes/Olympus%20SZ30/SZ30-01.jpg>
No problems found.

I think it's the LCD panel. There are replacement LCD's on Ali
Express and eBay for about $140. However, the scope is selling on
eBay for about the same price.
<https://www.ebay.com/sch/i.html?_nkw=owon+pds5022s>
This one has the same problem as mine:
<https://www.ebay.com/itm/285811299516>

If the DSO doesn't magically fix itself in the next few days, it's
going to the local recycler.

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

On Thu, 15 Aug 2024 13:42:12 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>On Wed, 14 Aug 2024 20:55:27 -0400, legg <legg@nospam.magma.ca> wrote:
>
>>On Wed, 14 Aug 2024 14:26:48 -0700, Jeff Liebermann <jeffl@cruzio.com>
>>wrote:
>>
>>>A few years ago, my Owon PDS 5022S oscilloscope failed with a strange
>>>looking display. See photo at:
>>><https://photos.app.goo.gl/rYGeaGygSMXHtMCb8>
>>>From what is visible on the display, everything seems to be working
>>>except for the strange display. Whatever is wrong is probably in
>>>either the color LCD display or the circuitry that drives the display.
>>>Does anyone have a clue what might have failed? Mostly, I'm trying to
>>>save time fixing it. (I haven't torn it apart yet).
>>>
>>>User manual (no schematic or block diagram):
>>><https://www.saelig.com/downloads/pds5022s.pdf>
>>>Specs:
>>><https://www.batronix.com/shop/oscilloscopes/digital-oscilloscope-pds5022s.html>
>>
>>Don't be afraid to open it up, just be carefull.
>
>I'm fearless and moderately careful. My problem is that I'm in the
>process of purging all the old junk from my house. When I retired and
>closed the office, I had to drag everything from the office to the
>house. The house has been a mess since Sept 2020. I have quite a bit
>of equipment that I know can be fixed if I had the time and bench
>space. For this DSO, the problem is both lack of time and lack of
>bench space. I can't just tear it apart and leave it. The reason I
>asked for clues is to save time monopolizing the workbench and
>troubleshooting the problem. In this case, I've seen literally
>hundreds of failed LCD computers displays, but none have ever looked
>like the photograph.
>
>>Could be something simple. I had a TDS210 that was shipped with a
>> reversed and burst electrolytic. Worked fine for a while before
>>requiring a simple fix. Display showed first symptoms.
>
>The DSO is old enough that a bad electrolytic is a likely problem. I
>couldn't find any information that would help establish the age. So,
>I measure a few voltages. If that fails, I find where my ESR tester
>is hiding and check every electrolytic.
>
>>The bloom around the LCD display looks physical, to me.
>
>There's no evidence of a crack in the display.

The pattern of 'bloom' looks like poisoning from an adhesive
layer.

>
>>As a battery-powered device, it'll have it's uses.
>
>It has an AC charger and power supply built in. The battery pack is
>proprietary. I plan to use the AC PS for testing and to build a
>suitable battery pack when it's fixed.

I crack mine open, replace the cells and add a balance w/test points,
then re-seal. I haven't 'adjusted' the EOC charge voltage yet.
Probably before the refurbed battery sets (always bought 2 with
each scope) are fried. Or a battery disconnect switch.

I use the mains 'off' switch when not in use and plugged in.
Never leave it quiescent and plugged in - that green light is
a fool's reassurance.

>
>Incidentally, I used it for about a year before it suddenly quit. It's
>only 20MHz bandwidth, but that was good enough for audio.
>
>>I have a few Owon SDS8202s that are eating their batteries
>>regularly. I've introduced balancing, internally, but the
>>charging circuit possibly overvolts the battery chemistry.
>>Simple is good, but ignoring the float upper limit is just
>>stupid.
>
>That's a much later 200MHz DSO:
><https://www.saelig.com/product/PSBEB100007.htm>

SDS was successor of PDS.

>The previous owner of my PDS5022s mentioned that overcharging the
>battery was also a problem. If it used LiIon and there was no BMS, I
>would not expect the battery to last very long. I have a few devices
>have no battery protection or balancing. When possible, I add the
>necessary circuitry. More commonly, I just bring out all the internal
>battery connections to a balancing connector and use a radio-control
>style external charger. I have one of these which will charge almost
>any battery:
><https://hobbyking.com/en_us/skyrc-imax-b6-v2-60w-6a-1-6s-dc-charger-discharger.html>

Battery management in the SDS is so rudimentary and ignorant of
internal ( ~third party) battery characteristics, that it can't
always manage to under-voltage reliably. One of mine corrupted
it's own firmware recycling on/off on a low battery in the
first few months and went back under warranty.

Software battery gauge is a joke.

Not all LiIon chemistries have the same EOC voltage - I think
the chemistry was changed after they shot the design engineer.
(Ship it!)

RL

On Thu, 15 Aug 2024 20:34:51 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>On Wed, 14 Aug 2024 14:26:48 -0700, Jeff Liebermann <jeffl@cruzio.com>
>wrote:
>
>>A few years ago, my Owon PDS 5022S oscilloscope failed with a strange
>>looking display. See photo at:
>><https://photos.app.goo.gl/rYGeaGygSMXHtMCb8>
>>From what is visible on the display, everything seems to be working
>>except for the strange display. Whatever is wrong is probably in
>>either the color LCD display or the circuitry that drives the display.
>>Does anyone have a clue what might have failed? Mostly, I'm trying to
>>save time fixing it. (I haven't torn it apart yet).
>>
>>User manual (no schematic or block diagram):
>><https://www.saelig.com/downloads/pds5022s.pdf>
>>Specs:
>><https://www.batronix.com/shop/oscilloscopes/digital-oscilloscope-pds5022s.html>
>
>Video of a Digimess DS25 DSO, which is similar to my Owon PDS5022s:
><https://www.youtube.com/watch?v=yfjh0KDEaTY>
>The plastic case, front panel, and oscilloscope section are identical.
>However, the LCD panel, power supply and backlighting inverter are
>very different.
>
>More videos:
>This PDS5022S video is 14 year old with upgraded firmware:
><https://www.youtube.com/watch?v=JQtvW1wpl6w>
>
>More of the same:
><https://www.youtube.com/shorts/6OCnuXpM2mY> (same problem as mine)
><https://www.youtube.com/watch?v=M0galCMhm7U>
><https://www.youtube.com/watch?v=nydo6xsLY7g>
><https://www.youtube.com/watch?v=hzZpE9yrMKA>
><https://www.youtube.com/watch?v=UInlOkFDf24> (shows defective LCD)
><https://www.youtube.com/watch?v=X1OTPt7_1Z8>
><https://www.youtube.com/watch?v=1sUGiwaEjq8> (shows defective LCD)
><https://www.youtube.com/watch?v=xHaapgrXxYI>
><https://www.youtube.com/watch?v=escwIX0vY64> (looks similar to mine)
><https://www.youtube.com/watch?v=EQXzP6sazaA>
><https://www.youtube.com/watch?v=MNzaAPetnVw>
><https://www.youtube.com/watch?v=K3mITKGuAW4>
><https://www.youtube.com/watch?v=bjRQP8mDCV0>
>
>Some photos of the internals:
><https://photos.app.goo.gl/ZgCRUB4SChDYRrRy6>
>When I removed the cover, I was immediately hit with the distinctive
>smell of burned resistor. I tried to find the source with my nose,
>but failed. When I "fire" it up again, I'll do some more fault
>"sniffing".
>
>Visual inspection didn't find anything that looked like a problem. I
>tested all the electrolytics with an ESR tester. I did another visual
>inspection with a microscope:
><https://www.learnbydestroying.com/jeffl/pics/microscopes/Olympus%20SZ30/SZ30-01.jpg>
>No problems found.
>
>I think it's the LCD panel. There are replacement LCD's on Ali
>Express and eBay for about $140. However, the scope is selling on
>eBay for about the same price.
><https://www.ebay.com/sch/i.html?_nkw=owon+pds5022s>
>This one has the same problem as mine:
><https://www.ebay.com/itm/285811299516>
>
>If the DSO doesn't magically fix itself in the next few days, it's
>going to the local recycler.

They're doing no-one any favors by making service info and replacement
parts unavailable.

Even so, stocking lcd displays for ten year gone product is
probably asking a bit much. Imagine if they did?

There's nothing particularly special about their circuitry, that
needs protection. It's all in the firmware. What needs protection
is the end user.

RL

+ User FidoNet address: 1:396/45
Hello All.

<On 15Aug2024 23:42 legg wrote a message to All regarding Re: Owon PDS 5022S >

l> On Thu, 15 Aug 2024 20:34:51 -0700, Jeff Liebermann
l> <jeffl@cruzio.com> wrote:

>On Wed, 14 Aug 2024 14:26:48 -0700, Jeff Liebermann <jeffl@cruzio.com>
>wrote:
>
>>A few years ago, my Owon PDS 5022S oscilloscope failed with a strange
>>looking display. See photo at:
>><https://photos.app.goo.gl/rYGeaGygSMXHtMCb8>
>>From what is visible on the display, everything seems to be working
>>except for the strange display. Whatever is wrong is probably in
>>either the color LCD display or the circuitry that drives the display.
>>Does anyone have a clue what might have failed? Mostly, I'm trying to
>>save time fixing it. (I haven't torn it apart yet).
>>
>>User manual (no schematic or block diagram):
>><https://www.saelig.com/downloads/pds5022s.pdf>
>>Specs:
>><https://www.batronix.com/shop/oscilloscopes/digital-oscilloscope-pd
>>s5022s.htm
l> l>
>
>Video of a Digimess DS25 DSO, which is similar to my Owon PDS5022s:
><https://www.youtube.com/watch?v=yfjh0KDEaTY>
>The plastic case, front panel, and oscilloscope section are identical.
>However, the LCD panel, power supply and backlighting inverter are
>very different.
>
>More videos:
>This PDS5022S video is 14 year old with upgraded firmware:
><https://www.youtube.com/watch?v=JQtvW1wpl6w>
>
>More of the same:
><https://www.youtube.com/shorts/6OCnuXpM2mY> (same problem as mine)
><https://www.youtube.com/watch?v=M0galCMhm7U>
><https://www.youtube.com/watch?v=nydo6xsLY7g>
><https://www.youtube.com/watch?v=hzZpE9yrMKA>
><https://www.youtube.com/watch?v=UInlOkFDf24> (shows defective LCD)
><https://www.youtube.com/watch?v=X1OTPt7_1Z8>
><https://www.youtube.com/watch?v=1sUGiwaEjq8> (shows defective LCD)
><https://www.youtube.com/watch?v=xHaapgrXxYI>
><https://www.youtube.com/watch?v=escwIX0vY64> (looks similar to mine)
><https://www.youtube.com/watch?v=EQXzP6sazaA>
><https://www.youtube.com/watch?v=MNzaAPetnVw>
><https://www.youtube.com/watch?v=K3mITKGuAW4>
><https://www.youtube.com/watch?v=bjRQP8mDCV0>
>
>Some photos of the internals:
><https://photos.app.goo.gl/ZgCRUB4SChDYRrRy6>
>When I removed the cover, I was immediately hit with the distinctive
>smell of burned resistor. I tried to find the source with my nose,
>but failed. When I "fire" it up again, I'll do some more fault
>"sniffing".
>
>Visual inspection didn't find anything that looked like a problem. I
>tested all the electrolytics with an ESR tester. I did another visual
>inspection with a microscope:
><https://www.learnbydestroying.com/jeffl/pics/microscopes/Olympus%20S
>Z30/SZ30-0
l> 1.jpg>
>No problems found.
>
>I think it's the LCD panel. There are replacement LCD's on Ali
>Express and eBay for about $140. However, the scope is selling on
>eBay for about the same price.
><https://www.ebay.com/sch/i.html?_nkw=owon+pds5022s>
>This one has the same problem as mine:
><https://www.ebay.com/itm/285811299516>
>
>If the DSO doesn't magically fix itself in the next few days, it's
>going to the local recycler.

l> They're doing no-one any favors by making service info and
l> replacement parts unavailable.

l> Even so, stocking lcd displays for ten year gone product is
l> probably asking a bit much. Imagine if they did?

l> There's nothing particularly special about their circuitry, that
l> needs protection. It's all in the firmware. What needs protection
l> is the end user.

Regrettably, the lack of service data prevades the system. I do professional
audio repair work... Been doing it for 56 years now. In the past, many if not
most manufacturers provided full-blown schematics/service manuals.That number
has dwindled down a LOT. Some of the so-called schematics re just partial with
blocks that show nothing, just lines connected to them. Useless. Same goes for
a few industrial units I work on. A complete non sequitur. You pay thousands
for a unit -- you expect it to be repairable. <frown>

Then there are the units that may be servicable, but one finds many of the
components slathered with silicone rubber se
alant... Again, unservicable. Frustrating, not only to me but to the client.

Best regards,
Marc Lewis, CET
Service Manager QTI Service Centre
Huntsville, AL USA
--
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ The FidoNet News Gate (Huntsville, AL - USA) +
+ The views of this user are strictly his or her own. +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++

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On Thu, 15 Aug 2024 20:34:51 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>If the DSO doesn't magically fix itself in the next few days, it's
>going to the local recycler.

I give up. I poked around for about 3 hours and determined that
everything seemed to be working except the LCD panel. Since a
replacement panel was not easily available and a used planel was
likely to have the same problem, I decided to recycle the DSO. I will
probably offer it as burnt offerings to the proper diety on the
barbeque or just pass it to the local recycler. Or, I might use it
for target practice.

My thanks to those who tried to help me fix it.

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558