Author Topic: Resistors for 33120A  (Read 1995 times)

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Offline Justincase1979

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Resistors for 33120A
« on: November 18, 2014, 08:23:42 pm »
Hello everyone, first post...

I am trying to fix a burnt out output attenuator in an Agilent 33120A. The resistors I need to replace are 69 ohm, 0.1%, 1206's, and these seem almost impossible to get a hold of in small quantities. Anyone have any good ideas as to where I could get hold of just a couple of these??
 

Offline KJDS

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Re: Resistors for 33120A
« Reply #1 on: November 18, 2014, 08:35:54 pm »
Have you tried some calculations of the affect of using a readily available resistor?

Offline Justincase1979

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Re: Resistors for 33120A
« Reply #2 on: November 18, 2014, 08:53:03 pm »
As far as I understand it would directly affect the accuracy of the output amplitude from the function generator, 1Vpp on the display would no longer equal 1Vpp output. But I haven't done any calculations as to the degree of change with other values, just wanted to see if it is at all possible to get a hold of the correct values first...
 

Online tautech

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Re: Resistors for 33120A
« Reply #3 on: November 18, 2014, 09:09:20 pm »
Why not stack 3 x 210 Ohm 1206 ?
Get say 10 x and select for value to get a spot on combination.
Avid Rabid Hobbyist
 

Offline brillopad

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Offline lowimpedance

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Re: Resistors for 33120A
« Reply #5 on: November 18, 2014, 10:16:34 pm »
Stacking is the best way to get what value you need, but be mindful of the temp co. as well.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline Justincase1979

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Re: Resistors for 33120A
« Reply #6 on: November 19, 2014, 10:48:47 am »
Ok, so I have decided to stack one 69.8 and one 6.04k, should give 69.003 total and both of these values are pretty easy to get hold of. My plan was getting .1%, 25ppm resistors, those specs should match the manufactureres parts acording to the manual.

One thing, is thin film the best option since we are dealing with freq up to 15MHz??
 

Offline Justincase1979

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Re: Resistors for 33120A
« Reply #7 on: November 28, 2014, 07:17:41 pm »
OK, new resistor in place and it works great, didn't even have to recalibrate it.

I also replaced the U205 SRAM to fix a 604 error, and that kind of worked. The 604 error disappeared, but now I get a 606 and 607 error. (They were probably there all along, just the self test that stopped at the 604 error.) Anyone have any idea where to start troubleshooting this??
 


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