Geller Labs
Geller Labs


The LeCroy LT344L

(work in progress, be sure to hit refresh to pick up our latest changes and entries)


Just a few rambling notes:

We were lucky to acquire a lightly used LeCroy LT344L Waverunner oscilloscope back around 2003. Now, 10 years from date of manufacture and with its 1.44 MB floppy drive showing like a long white beard, I am sad to say that it is close to antique status. (Perhaps not as bad as still using a tube Tek 545 though. What a wonderful old beast that one was!). Since many of these wonderful scopes are starting to show up on the surplus market, I will post some of my maintenance / repair notes / experiences here, perhaps to be helpful to other small (e.g. tiny) companies and amateur scientists looking to do minor repairs. Feel free to share your LeCroy LT series experiences with us (joegeller - at - gellerlabs dot com). (We will not post any codes or hacks that would violate LeCroy's hardware or software protected options).

While I mostly use it with GPIB and the LeCroy Scope Explorer software (the remote screen capture is very handy!), occassionally I still save panel setups and other data to floppy. Recently the floppy drive failed, so this first note is about hunting down a replacement. A little searching on the full part number printed on the drive itself brought out any number of options from new and used drives selling from $4.95 to well over $100 (used!). Some of the eBay sales noted what laptops use the same drive. Using that list, I recently ordered two brand new packaged plug in drives for the Compaq Armada laptop 7400. Soon, I will see if the "guts" yield the needed part! The part number of the exact drive hardware is: Citizen W1D FIL LR102061. It uses one of those very thin plastic coated 26 pin ribbon cables that slides into a very narrow connector on both the drive and the IWATSU CPU603e motherboard (perhaps an early "power pc"?), the top most board in the scope. An older DELL Latitude plug-in floppy module revealed that type of connection running to the DELL proprietory plug on the plug-in, so I am hoping to find a similar arrangement inside of the Compaq module. Also, I will likely be recycling the front panel bezel from the LT344L onto the new drive (it just snaps on). I suspect drives of that era (circa 2000) used a similar communication scheme, so probably(?) other drives with that standard(?) 26 pin ribbon connection would work fine too? I decided to go with the original exact part number to be safe. One eBay seller says that the floppies were made special for LeCroy. Of course that might be the same way Ford makes each pickup special for each and every driver :)

So, what happened?: Okay, the excellent news is that the $10 new old stock Compaq Armada laptop 7400 Citizen 5V, 700mA drive is almost identical to the LeCroy Citizen floppy drive, and it powered up fine in the LT344L and formated, saved, and recalled files fine!

The mounting holes were all the same. I does appear, however that there are small differences between otherwise nearly identically numbered Citizen floppy drives. The LeCroy Citizen plastic bezel locking arms did not perfectly fit the seeming slimilar slots and holes in the "new" Compaq Citizen drive. I broke one off trying to fit it, and eventually snapped the second one off to glue the bezel into the front panel. I used a thin layer of clear silicon adhesive to affix the bezel in the relatively thick metal front panel and all appeared to go well (will let it cure for 24 hours). The excess silicon wiped off cleanly and I don't think you can see it as different from before, plus now I have a little bit of a rubberized shock mount. Also, the new Citizen drive did not have the floppy drive activity LED installed. So, I took it from the old one and soldered it into the new one (pads were there) with no joy. The light is really not needed since there are front panel floppy text notices during all floppy operations and the floppy noises are also a good indication of floppy drive activity. I suspect for perfectionists, there is a "correct" very similar bezel for the Citizen drive from the Campaq production run ($10 new old stock from 1999). Also, I very much suspect that other laptop drives from era laptops (~2000), perhaps some with activity lights, with the 26 pin thin ribbon connection would work fine. There must have been some sort of standard for these types of drives. Okay, so the floppy drive is back, Yeah!

So, while I had the cover off, I couldn't help but notice that the mother board had two memory stick slots with one empty. The owners guide says that the mother board comes with 32 MB, but can support 64 MB. Thinking there might be some gain in calculation speed (e.g. math functions), especially for longer records (the "L" has up to 1 M points per acquisition), I am looking at adding the second 32 MB stick. Again, time will tell, will report back on the "experiment". The sticks appear to be 32 MB, EDO, 72 pin, 2k refresh (not 4k!), 16 chips (8 on either side), 60 ns RAM. I ordered two "matched" memory sticks from a memory company in PA, time will tell ... Fortunately, it does not run Windows!, so it is not clear what more RAM will accomplish. (I love Win 7 on my PC, but please no Windows on my scopes!!!)

While I'm poking around (this is the first time I opened the box and broke the LeCroy calibration seal) I started wondering about this rectangular connector with a removable metal cover on the back panel labeled WindRiver, VxWorks on the inside. Yikes!, then I realized it is a PC Bus (PCMCIA) laptop like port! The manual says it is for a removable hard drive, or SRAM card. LeCroy kindly answered my questions about this one. Apparently it is setup for a 512 MB memory (on my LT series anyway) and the current recommendation is to use a PCMCIA Sandisk adapter to compact flash (CF) with a Sandisk CF card. However, it requires a soft key to enable the hardware port (apparently this option then shows as HDS or HD01 in the installed hardware options). Of course virtually no one still uses card bus, pc bus, or PCMCIA cards (all newer laptops come with Express bus). So, needless to say all things (CF cards, CF adapters, etc) PC Card and PCMCIA are available for next to nothing on eBay, including the original Sandisk models.

So, what are these LT series units worth? They sold initially for $16k plus. Back around 2003, the price seemed to range from about $3,000 to $11,000. During several minor financial crisis, I've offered this one for sale, very fortunately without success! I turned down a $5,000 offer back around 2006. In 2011, it seems (albeit often well worn), this LT series can be had on eBay for between about $1,500 and $5,000. Although it has a 500 MHz analog bandwidth, in the RIS mode, the effective sample rates are well into the Gs range. They come in 2 channel and 4 channel models and the "L" models have a longer acquisition memory, 1 MB per channel. The math and measurement functions are outstanding for a general purpose scope. Also, there is a standard set of cursors if you want to fall back to an older fashion "simple" use style. For some recent jobs, I love my relatively "new" $200 repaired and calibrated hp 54645A (100 MHz, with long memory for "MegaZoom"). It is so simple to use and has solid measurment functions that work well with the long memory. However, there are a lot of other projects, where the LT344L was invaluable and needless to say far more powerful than the little hp. In fact, shortly after each time it was for sale, I ended up with a job where only the LT344L could make the needed measurement! It remains center stage on my bench.

I have since learned there is a relevant Yahoo Group (Thanks Sam!):






Tech Notes
About Geller Labs