Author Topic: Omega RD-2010  (Read 1152 times)

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Offline FloopyTopic starter

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Omega RD-2010
« on: June 12, 2018, 04:13:52 pm »
Hello,
Yet another repair on top of all the others I have to finish.

Here's my problem. I got this nice chart recorder the other day. Unfortunately it didn't come  with the power supply or anything else. The first thing I did was oil the rails and take it apart. I traced the power supply input jack all tha way back to a diode package. I assumed that the power input must be AC at around 10-20RMS. I couldn't find any schematics of the unit online so I had to assume. To make a long story short I left it on for about 30 seconds without a problem, when I reached over to turn on the function generator it went pop, flash of light and the magic smoke came out.

What could have caused this? Bad capacitors? The other capacitors look sketchy. Also what is the name of the blown semiconductor.

Thanks!
 

Offline FloopyTopic starter

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Re: Omega RD-2010
« Reply #1 on: June 12, 2018, 04:54:56 pm »
Okay I found the manual with schematic. The input requirement is 12VAC, I was putting 13VAC. I don't think it was my fault.
Manual below.
https://www.omega.com/manuals/manualpdf/M0455.pdf
 

Offline FloopyTopic starter

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Re: Omega RD-2010
« Reply #2 on: June 12, 2018, 06:31:25 pm »
Is that a L272M ?
That fried IC is what I'm stumped on.
Someone else posted about it, but they removed it.
 

Offline FloopyTopic starter

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Re: Omega RD-2010
« Reply #3 on: June 13, 2018, 02:21:23 am »
I cleaned the op amp and it says L272M, at least the visible portion. The pins that melted are all connected to each other. The fried pins of the 272 are connected to one of the input pins of the 324 which is fried also. The rest of the caps are bulging. Could this have been caused by the cap blowing? I can't remember which came first the burst of light or the pop. I think it was the pop, but I can't confirm. If so, can I just replace the fried parts and that would work fine afterwards?
 

Offline Kleinstein

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Re: Omega RD-2010
« Reply #4 on: August 03, 2018, 07:58:10 pm »
That damage looks really bad. It usually take more than just a bad cap - more like mains current flowing through the circuit or operating a 110 V instrument at some 400 - 600 V or maybe lightning strike (a milder case), maybe a rectifier giving full AC through (which is very rare).  With those blown parts chances are other parts are bad too.  It usually takes several (maybe 10s) l amps to blow the pins of a DIP chip.
 


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