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TDS3024B repair - CPU board issue. Anyone have schematics?

@Arcticgeek
 

Hi folks,


I have a TDS3024B scope that refuses to boot. The only thing that shows up on the LCD is a blank white screen. Obviously, the backlight is on but there is no video. I've ruled out an LCD issue because I can attach a TDS3GV option, and no video is present on the VGA output either. The relays should normally click during boot-up, this unit does nothing.


I've verified the AC power supply is fine, and I can also power the unit from the battery terminals using a lab supply. The unit behaves identical when powered from a lab supply on the battery terminals.


I have been probing around, and from what I can see all the voltages on the main board are there - +5V, -5V, +3.3V, and +2.5V and -2.5V for the acquisition section. The pgood/power on reset generator is working properly, reset is asserted during power on and de-asserted some ~100msec later. I can see access to the flash memory chip select for about 200usec, and then everything halts. Nothing is obviously wrong on the board, no burned components and nothing gets hot to the touch.


I thought perhaps the flash was corrupted, so I copied the flash contents from a working TDS3054B and made two copies of each flash chip. I put one set of the copied parts into the working TDS3054B, and it still works so I know my Eprom programmer worked okay. However, this had no affect on the failing TDS3024B.


At this point I'm stuck....and it would be REALLY helpful if I could find some schematics so I could know where to probe.


Does anyone have any schematics for the TDS3000 series scopes? Or know where I might find them? I already have the service manual downloaded from Tek, but it does not have any schematics and not really that helpful.


Thanks to all.

imettt
 

hi,i've had the same problem , the issue was solved with resolder with hot air the processor. take in account to don't move the processor during the operation, it's a bga!
my trick was put a weight on the processor ( few alluminium pieces) and use hot air over the 4 side.


you could test if the problem it's the same trying to press down with a finger during the power on.

amirb
 

did you fix your scope? if so, how?
I would replace the SRAM chips (one at a time) . It worked for me in a similar case

On Wed, Mar 8, 2017 at 12:18 PM, @Arcticgeek wrote:


Hi folks,


I have a TDS3024B scope that refuses to boot. The only thing that shows up
on the LCD is a blank white screen. Obviously, the backlight is on but there
is no video. I've ruled out an LCD issue because I can attach a TDS3GV
option, and no video is present on the VGA output either. The relays should
normally click during boot-up, this unit does nothing.


I've verified the AC power supply is fine, and I can also power the unit from
the battery terminals using a lab supply. The unit behaves identical when
powered from a lab supply on the battery terminals.


I have been probing around, and from what I can see all the voltages on the
main board are there - +5V, -5V, +3.3V, and +2.5V and -2.5V for the
acquisition section. The pgood/power on reset generator is working properly,
reset is asserted during power on and de-asserted some ~100msec later. I can
see access to the flash memory chip select for about 200usec, and then
everything halts. Nothing is obviously wrong on the board, no burned
components and nothing gets hot to the touch.


I thought perhaps the flash was corrupted, so I copied the flash contents
from a working TDS3054B and made two copies of each flash chip. I put one set
of the copied parts into the working TDS3054B, and it still works so I know my
Eprom programmer worked okay. However, this had no affect on the failing
TDS3024B.


At this point I'm stuck....and it would be REALLY helpful if I could find
some schematics so I could know where to probe.


Does anyone have any schematics for the TDS3000 series scopes? Or know
where I might find them? I already have the service manual downloaded from
Tek, but it does not have any schematics and not really that helpful.


Thanks to all.