A bit ago a semi-retired guy came back to help with some stuff including debugging serial ports. It was very cool to see him fiddle with the knobs and be like "oh those squiggles look good" "no that doesn't look right" etc. https://i.imgur.com/R5aEXbq.jpeg
Meanwhile total mystery to everyone else how to operate/interpret the machine but a lot of fun
I just had claude walk me through refurbishing a Rohde & Schwarz signal generator from the 90s. It feels pretty cool getting a multi thousand dollar piece of equipment for 60 bucks even if you have no idea what you'll use it for.
My model is an SMIQ03E actually! I've grown quite addicted to going to my local 2nd hand electronics store in recent months scrounging for anything with an rs232 port!
Very cool! Yeah I lucked out finding mine. It was in the intake section at my 2nd hand electronics store. It had a broken power button so they were selling it "as-is". A button repair and battery swap later I have a 3.3Ghz VNA. Can't complain!
Yeah 1 GHz is nice, but that tiny 200 MHz Siglent is going to be much more useful in practice for most things.
Speaking of boat anchors, I'm trying to get my company to buy a DSA91304a (13 GHz scope with SERDES debugging). ~$44K with all the options, but still Windows-XP. The Windows-7 ones unfortunately don't have the options I want. Maybe there is a hack..
As I wrote: the TDS7104 is now sitting on a shelf in the garage, next to an Agilent 54831 and some other boat anchors. My daily drivers are a Siglent scope and a puny TDS220, which is about to be replaced by a TDS3052 that I'm bringing back to life. Hobbyists rarely need more than 100 MHz BW.
I hope you're able to thoroughly test that DSA91304a before dropping $44k on it!
Yes, it's completely separate. There is a PCI2PCI bridge between the PC motherboard and the PowerPC controller board, which has in turn an interface PCB to the acquisition board.
People have replaced the RadiSys motherboard with one from a Gateway PC. There aren't a lot of other options though: the motherboard must be an NLX type and that was a short-lived format. It's different for scopes like the Agilent 54831 (https://tomverbeure.github.io/2026/03/28/Repair-of-Two-Agile...) that I revived a couple of months ago: people do crazy things with that, making it work with higher resolution LCD panels, upgrading to completely different CPU classes, running Windows 10 etc.
It's remarkable that these scopes have both a PC and a PowerPC motherboard. I think they were a reaction to Agilent scopes: they wanted a PC front-end and reused the PowerPC infrastructure with VxWorks OS that they already had from other generations, so they just slapped an extra motherboard on it.
Love this. I knew nothing about oscilloscopes until just a few months ago, when reasearched and bought one from a science lab. It wasfor a personal side project. I gutted it out and installed a mini PC inside, and now i run AI models into it. It's like my personal AI assistance. Hooked up to OpenAI realtime voice, grok bot, claude code, etc so I can command it to do stuff even when my main computer is off.
I just mainly love the retro-moder look of it. Here's a link to how it looks, for those curious:
Nice, so I'll get even more entertainment out of it!
The equipment that's bought and sold at the electronics flea market typically isn't used as a means to an end, it is the end. There's disappointment when you buy something there and it just works. There's no fun in that.
I went through a similar process recently with an HP/Agilent 54845A scope (1.5 Ghz, 8 Gsa combined) - a great tool if you need reasonably fast rise times and a reasonably fine time base resolution - the only issue is that it has an abysmally low sample memory for today's standards, so you get to see the trigger and "just a bit more". Well the other issue is that it pushes a lot of air... Like a lot, jumbo jet a lot. The scope luckily was in great shape and had a fresh test cert from not long ago.
I was going down the same route as the blog post (MSATA->PATA adapter), but simply imaging the HDD onto flash also didn't work.
The scope had to go into storage so I never finished this, but the SSD was being detected albeit at a lower capacity and no amount of twiddling with LBA and CHS geometry made a difference. My next step is going to be zeroing the drive, booting the scope with it as secondary, and then imagining it from within DOS/Windows. My hope is that the data will just end up at some offset. Or not even imaging it - just partitioning it, formatting it and doing XCOPY + SYS.
You may want to image the drive every so often and accessing the drive is a bit of a bastard (fewer than 32 screws on the HP but it's a pain regardless) - so it might make sense to actually get an SD->PATA adapter and mount it onto a PCI blanking plate, so that you can take it out easily. You may need a longer ribbon cable. There are also some 2.5 inch HDD brackets that mount onto a PCI blanking plate. Possibly a DIY job to replace the FDD with a plate that has the SD card mounted. Mine came with a ZIP drive.
I added the following software extras to the OS which I would recommend to anyone with an old scope like this that has an Ethernet port:
- An SNTP client so that you don't have to worry about the time and date (https://www.timesynctool.com/) - open source, win95 and up, just disable all logging to disk so as not to introduce extra writes and drive wear.
- TightVNC (1.3.10 I think) - a version that works on older Windows. Accessing it while the scope app is running slows things down significantly, so this is only for configuration changes and whatnot, also this particular scope writes directly to the VGA framebuffer, so you don't actually get to see the scope output via VNC!
- Shared some folders from the scope. This required a significant amount of fuckery to mount an SMB1 drive elsewhere without ruining one's existing Samba config, but it helps quite a bit to be able to exchange files with the scope.
Hardware extras that proved useful in a lab setting:
- One of those cheap VGA to USB frame grabber adapter things - they are detected as a video device, don't need drivers and you can watch your scope with VLC or your OS's built-in camera app.
- A remote-controlled power outlet. Speaks for itself - no need to touch the scope to shut down and restart an experiment from wherever you are.
- A GPIB to USB adapter if your scope has a GPIB/IEEE 488 port. Current Linux support is in a bit of a state, but anyway, this will allow you some degree of automation when reading the math / stats / other data, and will sometimes allow you to do more than the scope's UI will. I know for example that with GPIB I can control the signal on the AUX port on my scope, for which the GUI has no options.
- Not tried yet: this scope uses a PS/2 mouse (remember that they are not hot-pluggable) and a DIN keyboard. This bad boy: https://github.com/rasteri/HIDman - will let you plug in your wireless USB dongle and control your scope with your everyday keyboard and mouse.
The above significantly improves the "workflow" so that you hardly need to touch your scope or even swing your chair, or can use it remotely, and applies to most of the late 90s - early 2000s Windows scopes.
Not sure if you saw it, but before doing the TDS7104, I refurbished two Agilent 54831 scopes: https://tomverbeure.github.io/2026/03/28/Repair-of-Two-Agile.... For the one that still had a HD, copying the image from to an SSD worked without any issues. However, I also had a 54825A where it didn't work (I sold it, no blog post about that one.) So it's clearly hit-and-miss.
I found the 32 screws of the TDS7104 less of a pain than the dismantling the Agilents which had less screws.
> I found the 32 screws of the TDS7104 less of a pain than the dismantling the Agilents which had less screws.
Yeah sliding the whole thing out of the shell and the (curses) front panel ribbon that gets in the way, and the best part is that if it pops out on the front panel end, the tab is held in place by a metal prong that you have to bend (break away) to undo the tab to secure the ribbon. The prong is not screwed down, it's riveted. Breaking that thing away was the best thing I could do without ruining the panel. I ended up also gluing that ribbon to the chassis so that it doesn't get caught again.
Edit: I also bought mine to use it, hence all the extra bits around it.
My 54825A had a power-up problem: if you unplugged the AC cord for a few hours, pressing the front-panel button wouldn't power on the scope. But if you plugged in the AC for about 5 minutes, it would work fine again.
That sounds like an easy thing to fix, but the whole power-on architecture was a baffling Rube Goldberg device from the button on a small support PCB to the front panel PCB to the PC plug-in card to the power supply. I've never seen anything like it.
I disclosed the flaw to the buyer (the price was very low) and he was excited to have something to work on. :-)
There are exceptions to the "Winscopes" from the same era in the 1 GHz+ space (RTOS like VxWorks but with Ethernet and modern goodies) that are not HP/Tek/R&S, but I'm not listing them because I'm out on an active hunt for one ;-)
Meanwhile total mystery to everyone else how to operate/interpret the machine but a lot of fun
And yes, it's a lot of fun bringing these bargain bin pieces of kit back to life.
It can be used a vector RF signal generator with I/Q inputs. The only limitation is the reduced input bandwidth.
Speaking of boat anchors, I'm trying to get my company to buy a DSA91304a (13 GHz scope with SERDES debugging). ~$44K with all the options, but still Windows-XP. The Windows-7 ones unfortunately don't have the options I want. Maybe there is a hack..
I hope you're able to thoroughly test that DSA91304a before dropping $44k on it!
I'm just wondering how difficult it would be to use a more modern bit of kit in there instead of the Celeron.
People have replaced the RadiSys motherboard with one from a Gateway PC. There aren't a lot of other options though: the motherboard must be an NLX type and that was a short-lived format. It's different for scopes like the Agilent 54831 (https://tomverbeure.github.io/2026/03/28/Repair-of-Two-Agile...) that I revived a couple of months ago: people do crazy things with that, making it work with higher resolution LCD panels, upgrading to completely different CPU classes, running Windows 10 etc.
It's remarkable that these scopes have both a PC and a PowerPC motherboard. I think they were a reaction to Agilent scopes: they wanted a PC front-end and reused the PowerPC infrastructure with VxWorks OS that they already had from other generations, so they just slapped an extra motherboard on it.
I just mainly love the retro-moder look of it. Here's a link to how it looks, for those curious:
https://x.com/slhomme/status/1965131874734584291
I had now idea there was such a huge second-hand market for those. It was such a great opportunity to learn about this tech.
Still, entering an easy to generate license key is less intrusive than removing a resistor.
The equipment that's bought and sold at the electronics flea market typically isn't used as a means to an end, it is the end. There's disappointment when you buy something there and it just works. There's no fun in that.
I don't really have a use for a R&S AMIQ, but replacing all the PC motherboard caps taught me a lot about good desoldering practices. https://tomverbeure.github.io/2026/06/28/Rohde-Schwarz-AMIQ-...
These are just exceptionally bad.
I was going down the same route as the blog post (MSATA->PATA adapter), but simply imaging the HDD onto flash also didn't work.
The scope had to go into storage so I never finished this, but the SSD was being detected albeit at a lower capacity and no amount of twiddling with LBA and CHS geometry made a difference. My next step is going to be zeroing the drive, booting the scope with it as secondary, and then imagining it from within DOS/Windows. My hope is that the data will just end up at some offset. Or not even imaging it - just partitioning it, formatting it and doing XCOPY + SYS.
You may want to image the drive every so often and accessing the drive is a bit of a bastard (fewer than 32 screws on the HP but it's a pain regardless) - so it might make sense to actually get an SD->PATA adapter and mount it onto a PCI blanking plate, so that you can take it out easily. You may need a longer ribbon cable. There are also some 2.5 inch HDD brackets that mount onto a PCI blanking plate. Possibly a DIY job to replace the FDD with a plate that has the SD card mounted. Mine came with a ZIP drive.
I added the following software extras to the OS which I would recommend to anyone with an old scope like this that has an Ethernet port:
- An SNTP client so that you don't have to worry about the time and date (https://www.timesynctool.com/) - open source, win95 and up, just disable all logging to disk so as not to introduce extra writes and drive wear.
- TightVNC (1.3.10 I think) - a version that works on older Windows. Accessing it while the scope app is running slows things down significantly, so this is only for configuration changes and whatnot, also this particular scope writes directly to the VGA framebuffer, so you don't actually get to see the scope output via VNC!
- Shared some folders from the scope. This required a significant amount of fuckery to mount an SMB1 drive elsewhere without ruining one's existing Samba config, but it helps quite a bit to be able to exchange files with the scope.
Hardware extras that proved useful in a lab setting:
- One of those cheap VGA to USB frame grabber adapter things - they are detected as a video device, don't need drivers and you can watch your scope with VLC or your OS's built-in camera app.
- A remote-controlled power outlet. Speaks for itself - no need to touch the scope to shut down and restart an experiment from wherever you are.
- A GPIB to USB adapter if your scope has a GPIB/IEEE 488 port. Current Linux support is in a bit of a state, but anyway, this will allow you some degree of automation when reading the math / stats / other data, and will sometimes allow you to do more than the scope's UI will. I know for example that with GPIB I can control the signal on the AUX port on my scope, for which the GUI has no options.
- Not tried yet: this scope uses a PS/2 mouse (remember that they are not hot-pluggable) and a DIN keyboard. This bad boy: https://github.com/rasteri/HIDman - will let you plug in your wireless USB dongle and control your scope with your everyday keyboard and mouse.
The above significantly improves the "workflow" so that you hardly need to touch your scope or even swing your chair, or can use it remotely, and applies to most of the late 90s - early 2000s Windows scopes.
I found the 32 screws of the TDS7104 less of a pain than the dismantling the Agilents which had less screws.
Yeah sliding the whole thing out of the shell and the (curses) front panel ribbon that gets in the way, and the best part is that if it pops out on the front panel end, the tab is held in place by a metal prong that you have to bend (break away) to undo the tab to secure the ribbon. The prong is not screwed down, it's riveted. Breaking that thing away was the best thing I could do without ruining the panel. I ended up also gluing that ribbon to the chassis so that it doesn't get caught again.
Edit: I also bought mine to use it, hence all the extra bits around it.
That sounds like an easy thing to fix, but the whole power-on architecture was a baffling Rube Goldberg device from the button on a small support PCB to the front panel PCB to the PC plug-in card to the power supply. I've never seen anything like it.
I disclosed the flaw to the buyer (the price was very low) and he was excited to have something to work on. :-)