Tektronix TDS540 Oscilloscope

[Scott Broom]

Hello,
Brand new to the Forum and would appreciate any help with my scope issue.
I recently purchased a Tektronix TDS540 Oscilloscope from EBay and I am aware of the capacitor issues. I have the capacitors in hand but have not replaced them yet. I have not powered the unit on yet because I wanted to perform a visual inspection of the boards for capacitor leakage / corrosion, etc. first. It seems to be fairly clean but will check and clean as necessary.

I found a burnt surface mount resistor on the DRAM Processor / Display board and cannot read the reference # (Rxxxx) or tell its value. I have enclosed pictures of its location on the board. It is in the front part of the board near U171, U172, C62, C1225
I do have the Service Manual but no schematic and have not performed any troubleshooting at this time.

I would like to replace this resistor, repair the burnt board and replace the capacitors, clean board before powering up the unit. I would think this is a multi layer board and hope other traces are not damaged.

Need help determining the resistor value and what may have caused this. Hopefully someone may have seen this before.

DRAM Processor / Display Board - G92-0658-02 (Label # 671-1477-01)

Thanks for the help, Scott

 

[(*steve*)]

Are you still able to read the value of that resistor?

 

[Scott Broom]

Unfortunately, no. Even if I was able to read a value with an Ohmmeter, I would imagine the value would have changed. Thanks!

 

[(*steve*)]

That's what I mean. Use a multimeter.

 

[Scott Broom]

I have with an ohmmeter - out of circuit. It is open.

 

[(*steve*)]

For future reference, it's worth trying to read the value in circuit before you remove it, just in case it disintegrates (or is further damaged) as you remove it.

Now you have removed the resistor, show us the board. It looks like it may be chatted enough to cause problems.

Also try to find out what both ends of the resistor are connected to. This will probably help us figure out what caused this resistor to burn up.

If the capacitors in this scope have any history of failing short circuit, it may be a good time to check them

 

[Scott Broom]

After a little more research, I determined the reference # of this resistor is “R1037”.

I’m curious if anyone has a schematic of the TDS540 or of another scope in this series that might be close in this area.
Not only do I need the resistor value but probably have traces damaged and will need to patch the open ones.
This is going to be a fun challenge.