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!
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.
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!
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 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.
Was that by any chance the R&S AMIQ that I refurbished in an earlier blog post?
And yes, it's a lot of fun bringing these bargain bin pieces of kit back to life.
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!
I looked for a SMIQ for quite a while to go along with the AMIQ, but eventually settled for the R&S SFQ TV test transmitter that you can see here: https://tomverbeure.github.io/2026/06/28/Rohde-Schwarz-AMIQ-....
It can be used a vector RF signal generator with I/Q inputs. The only limitation is the reduced input bandwidth.
Is the PC mainboard separate from all the tek ASIC etc stuff? If so, what's the interface? PCMCIA? PCI?
I'm just wondering how difficult it would be to use a more modern bit of kit in there instead of the Celeron.
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.
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!
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:
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.
The TDS500, 600 and 700 series can expand memory by removing zero ohm resistors.
My TDS754D is waiting for the resistor and capacitor mod that converts it from a 500MHz/2Gsps scope into a TDS784D with 1 GHz/4Gsps.
Still, entering an easy to generate license key is less intrusive than removing a resistor.
Give it a month and the acquisition ASICs will blow up and the caps will eat through the board traces. Can’t stand these scopes.
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 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-...
Yeah agreed. I’ve fixed more Tek equipment than most people out there. In the order of hundreds of units.
These are just exceptionally bad.
Flebay has some used ones around $1.5k. I wonder how much this model MSRP brand new? Either way, $300 is a steal!
I think they sold for $60k back in the early 2000s.
I remember seeing the Logic Analyzer from that same series in a lab I worked in in the early 2010s, was told it cost as much as a house at the time.