HP 54121 part wanted

They were available from Agilent about 2 years ago on an exchange bassis. The part number for the exchange (they need the bad unit back) was 5086-6471 and cost around $ 800 US. Usually when the TDR got wacked so did the sampler that follows the TDR block, sampler costs about $ 500 and is exchanged too. Static damage in the dry winter climate was a common problem. We used to put big Static warnings labels on the 54121 cover. I've changed hundreds (samplers & tdr's) since 1987. We recommended people not to use Channel 1 unless they were doing TDR work because they would damage both TDR & sampler blocks. Channels 2,3 & 4 don't have TDR's, as you know. Good Luck.......

-- change .combo to .com for correct email

***************************************************

Thanks Kevin. The sampler is ok 'cause I'd already repaired the TDR (we do that down here where we're far from civilisation !!) - a Schottky diode gate/bias network inside was zapped but new ones glued in using a microscope and silver paint got it going again. Trouble is the step is now a bit slower (80 odd ps vs < 50) and a bit more lumpy. Now that I have more critical work to do, I again want the good spec, but I guess Agilent will not want the doctored unit so I either purchase new, get one from a trashed scope, or use an external step generator ??

Wow, what finese in repairing the TDR ! I don't know what to tell you. Maybe pick up a 54121 test set and use it for parts and hoping the TDR is good.

-- change .combo to .com for correct email

***************************************************

bassis.

I've

not

damage

know.