Electronics > Repair

OCXO repair, is it possible?

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ZGoode:
So I bought two Morion MV89A, one for use in a GPSDO and the other for upgrading the timebase in my 53131A.  Turns out one of them is totally dead, of course its the one in better physical condition too, since the one that works had a completely sheared off ground pin.  I ended up making a new pin on a lathe out of brass, which seems to have repaired the one with a missing pin, so I'm at 1 for 1 so far.
The other one is a little more complicated, since it has zero signal output.  It heats up, so the oven works, but no output.  What are the odds this is salvageable?  I saw some people mentioned I might be able to open it with a blowtorch or high power heat gun, but wanted some input before I did the irreversible.
From anyone who has opened up a soldered case OXCO before what worked best for you?

Edit: I did find a post by someone using the exact same OCXO as me, but would still love some input before getting out the torch.  https://rbarrios.com/projects/mv89a/

ZGoode:
Well, managed to crack it open with the power of a heater plate, FR301, and a heat gun.  Now it's time for an autopsy and to see if we can figure out what is borked here.

smaultre:
They used acid flux that breaks the solder joints, on some series. You can try to open and clean\re-solder bad connections...

Stray Electron:

--- Quote from: smaultre on August 31, 2024, 06:29:39 am ---They used acid flux that breaks the solder joints, on some series. You can try to open and clean\re-solder bad connections...

--- End quote ---


   WTF?  I've never heard of using acid flux to unsolder anything and I don't know why acid flux would work any better for that than any non-acid flux.  Flux is intended to clean a surface before soldering to it, not as an aid for unsoldering. Furthermore, I would think that if you used acid flux on anything electrical that unless you can remove every trace of it (unlikely in the case of a soon to be sealed OCXO) that sooner or later the acid would creep into the electrical circuits and corrode and ruin them. 

   There are several threads in this forum and online where people have opened OCXOs and repaired them.   

    IMO acid flux has no place in electronics, period.

Gerhard_dk4xp:
This is what is inside:
<      https://www.flickr.com/photos/137684711@N07/49585174873/in/album-72157662535945536/       >

One of my MV-89A stopped oscillating when the tuning voltage was > 1V.
The tuning range drifts when they age, and these MV89s on ebay
already had a life on a Chinese telecom tower behind them.

I just took the 5 MHz SC cut crystal. Yes, the 10 MHz oscillator has a
frequency doubler, and it shows on the output.

Gerhard

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