I made them an offer they shouldn't have refused, namely to tell them how to fix a bunch of their broken sampling gear in exchange for a decent price break. They didn't go for it.
Fine; that leaves more broken gear on the market that I can buy cheap and fix.
John
Many used test equipment vendors don't have the means or abilities to repair anything even if they wanted to. I'm frankly surprised just how low-tech a lot of these operations are; many just know the description of the item and wouldn't have the foggiest notion as to how to use it.
You're right about equipment being cheap right now... I picked up a Tek 8561E
6GHz spectrum analyzer for a song; down to under 1/10th the original price for a 10-year-old instrument. :-)---Joel
Question: You've mentioned dead EEPROMs a few times here. How do you determine what data has to go into the new one?
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
One thing that you might find relevant is that faults sometimes just go away. I bought a 54112 scope on Ebay for 40 ukp last year, which had memory and module post test failures. The first thing was to remove all the boards, clean the edge connectors etc and reseat, but the module post still failed. I left the thing on for a week solid, then repowered up and while the post test passed, one of the 4 channels was quite noisy. Left it running for a few more days and the noise went away and it's been good since. Even ran the calibration procedure fine as well.
Thinking about it, the failure mode seems to be one of damp getting into the ic packages and causing leakage. A lot of the older test gear may have been left in unheated stores for many years prior to disposal and a thorough baking seems to be quite good for them. Have recovered a couple of other instruments this way as well...
Regards,
Chris
Agreed. I bought a nice TLA704 logic analyser with acq. module and probes for 300 US$. Thats at least 1/50th of the original price. Maybe the seller would have knocked off another 100 US$ the next round but I didn't want to risk that. All it needed to get going was a new hard drive (=the hard drive from my old laptop). Being able to fix this sort of stuff really pays off.
It did make me think about the depreciation of measurement equipment. Its worse than cars!
--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
"If it doesn\'t fit, use a bigger hammer!"
--------------------------------------------------------------
Clone the chip in a working unit.
-- The movie \'Deliverance\' isn\'t a documentary!
Works fine here but I am only 100 miles from John so latencies are much smaller than the usual 200msec between here and Europe.
Check whether your router has a setting called "fragmentation". If disabled this could cause the problem.
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Yup. Then recalibrate.
John
It took me a while, but I finally convinced the cal lab at Microdyne to read and archive every EPROM in everything they serviced, for future use.
-- The movie \'Deliverance\' isn\'t a documentary!
Hi,
I had a similar problem. Using a proxy for FTP solved the problem for me.
Best regards, Herbert
These Tek 11801-type scopes sometimes throw an error on powerup and while running. Many of them just go away.
John
In all fairness I already suspected the 93c46 clone and replace might work, but they didn't even *ask* me. I'm the mushroom that works in the basement. (Keep me in the dark and feed me shit)
We've only got 1 sampling head in the "graveyard" right now. It's a 50GHz SD-32. It's not a potential for EEPROM replacement as it causes the 11801 to fail with a TXXXX timing error on power up. Perhaps it's bus related; even a pinout on these things might be helpful.
If they have microprocessor control, another thing to watch out for is the static ram chips in some early micro controlled test gear. I had some hard fail on a Fluke calibrator which was confirmed by swapping the
2 ram chips round between sockets. The micro was locking up on startup, so a ram failure in a different area resulted in a different set of leds left lit on the front panel.Processor chips fail as well, as does cd4xxx cmos, but ttl seems remarkably resilient...
Regards,
Chris
Right. Just got the CSA803 today and tested the SD24 head.
Both channels are working in sampling mode, but only one has the step pulse generator working.
Anyway TRDing the dead channel with the good one show some impedance modification when toggling the (dead channel) input on/off and ditto for the dead step generator, so I'll open it up and have a look. With a bit of luck it might be a broken bonding wire (I don't believe someone could actually kill the step pulse generator without killing the sampler...)
-- Thanks, Fred.
Unless you need to do true differential TDR, that head will be useful.
I like to use the step generator as a signal source. You can TDT passive networks like that, or even use the TDR step as the input to amplifiers and such.
Oh, one famous SD24 bug: the blinking "TDR" led causes some small time shifts in the sampling circuitry as it winks on and off.
John
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