DSO138 Firmware and Hardware upgrade

Thread Starter

blackwolfman

Joined Dec 11, 2022
3
Hello

Just got myself one of these, and a 10/1 probe.
My aim is to see an eye pattern in order to repair an old Technics CD Player.
Do I need 2 channels to do this? Digital or analogue?

If I do, I found this mod to get two analogue and two digital channels going:
https://github.com/ardyesp/DLO-138/blob/master/pics/HardwareMod.png

Just needed some guidance in understanding the mod. My current understanding is:

ON SEN2 section
From C8 120pF (-)ve leg hook up a wire to
-> the leg of
MCU TP11 / #11/ / PA4

next
Cut the trace between the R15 1K and R14
hook up a wire before the cut to the Trigger
after the cut trace, hook up a wire to the source

There is a blue line between the trigger and source
then there is another line to SWDIO before the R24 that eventually runs to the #2 pin of the SWD port for Digital 1 and 2 channels

My question is, is all this necessary or will the new firmware work automatically without these hardware mods? I cannot seem to find an easy to understand guide begin noob at oscilloscopes. Thanks for your patience
 

JohnInTX

Joined Jun 26, 2012
4,787
Welcome to AAC!
I don't know if what you are proposing will work but I've attached the full schematic of at least one version of the DSO138. Your scheme replicates the analog channel and buggers up the trigger to support both. Do you anticipate that the firmware will work with 2 channels?
Good luck!
 

Attachments

Thread Starter

blackwolfman

Joined Dec 11, 2022
3
Thanks everyone for your input and advice on the DSO138 el cheapie. Others have verified the firmware and mod will work with 2 channels albeit with further restrictions. As I was waiting for the unit to arrive, I began the bedtime reading:) above I spontaneously found an older analogue oscilloscope on FBMarketplace. It is a BWD-539 with two channels and probes. Starting to put things together, and understand how CD players work and how to troubleshoot for beginners. Thanks all.

Update: the el cheapie arrived in mail in a padded bag and upon boot found the screen to be broken. Not a good start! I wont be wasting more time with this and looking at putting the return funds towards another proper unit. Back to CD player repair research :)
 

Attachments

tautech

Joined Oct 8, 2019
377
above I spontaneously found an older analogue oscilloscope on FBMarketplace. It is a BWD-539 with two channels and probes.
Old outdated CRO, Aussie made. Parts no longer available however they did use a lot of common and still available components and if you want to enter a hobby of fixing aging CRO's, BWD is a good choice as any as the manual is available from Kevin Chant's website:
https://www.kevinchant.com/uploads/7/1/0/8/7108231/bwd539d_oscilloscope.pdf

TBH you'd be better served by a modern DSO that didn't require maintenance/fixing to pursue your hobby like I discovered some 2 decades ago.
YMMV
 

Thread Starter

blackwolfman

Joined Dec 11, 2022
3
Thanks everyone for your input and advice on the DSO138 el cheapie. Others have verified the firmware and mod will work with 2 channels albeit with further restrictions. As I was waiting for the unit to arrive, I began the bedtime reading :) above and spontaneously found an older analogue oscilloscope on FB MArketplace. It is a BWD-539 with two channels and probes. Starting to put things together, and understand how CD players work and how to troubleshoot for beginners. Thanks all.

Update: the el cheapie arrived in mail in a padded bag and upon boot found the screen to be broken. Not a good start! I wont be wasting mor etime with this and looking at putting the return funds towards another proper unit. Back to CD player repair research :)

Old outdated CRO, Aussie made. Parts no longer available however they did use a lot of common and still available components and if you want to enter a hobby of fixing aging CRO's, BWD is a good choice as any as the manual is available from Kevin Chant's website:
https://www.kevinchant.com/uploads/7/1/0/8/7108231/bwd539d_oscilloscope.pdf

TBH you'd be better served by a modern DSO that didn't require maintenance/fixing to pursue your hobby like I discovered some 2 decades ago.
YMMV
Thanks for the advice. Yes an older item but in pritstine condition and despite its age (c.1970s) well looked after by an ex Telstar engineer - and I received a refund on the trash Chinese DSO138, so money redirected.

Its the 539A so there is another manual more specific to it if it helps others:
https://www.kevinchant.com/uploads/7/1/0/8/7108231/539a_cro.pdf
http://www.harvey.edwards.net/HowtouseaBWD539Oscilloscope.pdf

Im getting some lovely trace lines for the time being so Im learning a lot as long as it lasts.

Cheers
 
Top