Author Topic: Obtaining Resistor Values from Printed Hybrid Modules?  (Read 442 times)

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Offline Chris56000

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Obtaining Resistor Values from Printed Hybrid Modules?
« on: August 15, 2018, 12:21:29 pm »
Hi!

Just a quickie one!

Can anyone point me in the direction of techniques that will help me measure the printed resistor values on ceramic hybrid modules?

I come across great numbers of these in the Industrial Electronics Repair I'm employed in – I know chaps on here & elsewhere have reverse–engineered some of these to rebuild them in more conventional form!

Chris Williams
It's an enigma that's what it is!! This thing's not fixed because it doesn't want to be fixed!!
 

Offline CJay

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Re: Obtaining Resistor Values from Printed Hybrid Modules?
« Reply #1 on: August 15, 2018, 12:38:48 pm »
Hi!

Just a quickie one!

Can anyone point me in the direction of techniques that will help me measure the printed resistor values on ceramic hybrid modules?

I come across great numbers of these in the Industrial Electronics Repair I'm employed in – I know chaps on here & elsewhere have reverse–engineered some of these to rebuild them in more conventional form!

Chris Williams

I've reversed a few, I've only ever used a multimeter, it's handy if you have a hybrid you can remove all the other parts from of course.

They're not always (rarely?) standard values so don't panic if you see 'odd' values but you of course need to take into consideration the surrounding components, the resistors are often laser trimmed on test as well  (you can see the laser marks which is rather cool)
 

Offline schmitt trigger

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Re: Obtaining Resistor Values from Printed Hybrid Modules?
« Reply #2 on: August 15, 2018, 12:48:00 pm »
As a matter of fact, one of the big pros with hybrid circuits is the resistance-value trimming capabilities. So you will find all sorts of nonstandard values.
 

Offline CJay

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Re: Obtaining Resistor Values from Printed Hybrid Modules?
« Reply #3 on: August 15, 2018, 01:20:03 pm »
As a matter of fact, one of the big pros with hybrid circuits is the resistance-value trimming capabilities. So you will find all sorts of nonstandard values.

It is indeed, I've seen plenty with trimmed or really 'odd' values however on a good number of the ones I've reversed the designers had just transcribed a design with standard values so they were all close enough to off the shelf parts to make it trivial to replicate
 


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