Electronics > Repair

Broke my TDS3000B

(1/7) > >>

perdrix:
A bit ago I reported a problem with ripple on calibrator trace if my TDS3014B (up-hacked to TDS3064B): https://www.eevblog.com/forum/testgear/tds3000b-trace-ripple/msg3492464/#msg3492464

I replaced the tantalum caps on the main board and that problem is gone, but I've broken it - I got a bit of solder splatter on a few pins of what I suspect is the main CPU (the one marked EX388/ADG360C/MM9595-AUW/156-7644-01) and on two pins of one of four ICs marked ES336AC/ADG361D/MM9916-VJG/156-7645-01 which I failed to notice and powered it on in that state.  :-BROKE

I've since removed the splatter but now any horizontal sweep rate faster the 400uS breaks up into a mess, and autoset doesn't work right.  I'm thinking I've probably killed it  >:(

Of course it happily passes the self test.

Before I put on my scrap pile and weep over the loss of a nice scope has anyone any thoughts - I've carefully re-checked for any further solder bridges - none found.

David

YetAnotherTechie:
have you cleaned all the fux residue? even underneath? solder can stick in the pins up to the package, an be hard to see except at certain angles.

sicco:
The MM9595 is not the main CPU. The PowerPC XPC860 is. But this MM9595 does autonomously do the graphics, and gets the traces of the four channels plotted, even if the PowerPC is halted.

Suggest you check for shorts once again, in neighboring pins, beep it through with a multimeter and needle probes... Some pins are interconnect because they’re power supply, GND etc. But the bulk of the ~400 pins are not...

Before you scrap it, consider selling as-is for parts on eBay. Adventurists (like me) may bid more than you’’d expect!

perdrix:
I've just put it back together after yet another cleaning session, but with no change ☹

However I do have something to report which may be useful:  If I bring up the acquire menu, and select "Fast Trigger" (500 points), then the calibrator wave form is display correctly down to a sweep speed of 20us/div (400us/div in "Normal Resolution" mode). If I go down 10us/div it all breaks up into a mush again.

I'm sure this means something useful to someone who knows more about how this beastie works.

PS I beeped out the pins as suggested, and no shorts to be found ...

David

perdrix:
Here's what I see when I switch from 400us/div (normal calibrator square wave) to 200us/div - oops:



SPC fails as well

All channels fail in the same way :(

David

Navigation

[0] Message Index

[#] Next page