DOD Digitech Two Second Digital Sampler PDS2000

[opacheco]

Hi,

Do you know where I can find the DOD Digitech Two Second Digital Sampler PDS2000 Schematic???...I have a unit of this and the IC U21 with the number MT 1257-20 print on is very hot all the time.....Do someone know what is this IC???.....Do you have seen this problem before???

Any comments will be appreciated.
Opacheco.

[doctor]

Hi,

Do you know where I can find the DOD Digitech Two Second Digital Sampler PDS2000 Schematic???...I have a unit of this and the IC U21 with the number MT 1257-20 print on is very hot all the time.....Do someone know what is this IC???.....Do you have seen this problem before???

Any comments will be appreciated.
Opacheco.

IC21 MT1257-20 is 256Kx1 DRAM manufactured by Micron Technology Inc.
As a rule DRAM is hot when CAS and/or RAS control signal is absent.

I have this schematic and I will scan and upload it in the next few days.

[opacheco]

IC21 MT1257-20 is 256Kx1 DRAM manufactured by Micron Technology Inc.
As a rule DRAM is hot when CAS and/or RAS control signal is absent.

I have this schematic and I will scan and upload it in the next few days.

Thanks Doctor for your response and help!!...I will be wait for it....But what "CAS and/or RAS control signal is absent" mean????......

Thanks a lot again.
Opacheco.

[doctor]

Thanks Doctor for your response and help!!...I will be wait for it....But what "CAS and/or RAS control signal is absent" mean????......

Thanks a lot again.
Opacheco.

DRAM chip contains the dual dimension matrix of memory cells.
Signals CAS (Column Address Select) and RAS (Row Address
Select) are basic for DRAM and used for selecting a specific cell.

If your knowledge will be insufficient to fix PDS-2000,
I would recommend to you to address to professional
technician specializing on digital devices repair.

Attached schematics will be useful.

[opacheco]

Doctor, Thanks a lot for your help and advises!!

Do someone have had similar trouble with this unit???

Thanks a lot again,
Opacheco.

[Skeletor69]

Hello...
Doctor i need help.. i found out that My PDS 2000 has a busted capacitor (16v 10uf) series w/ PN100 transistor.. how can i fix this and how to troubleshoot it?? (^^,)

[g1]

repost of schematic