[time-nuts] Reverse-engineering LPRO

Bob Camp lists at rtty.us
Mon Feb 18 08:20:10 EST 2013


Hi

I think the truth of the matter is that these gizmos have been cheap enough (and complicated enough) that they don't get repaired a lot. Certainly the VCXO gets tweaked, and there are a couple of caps that explode / get replaced. Past that either they don't break, or they get replaced.

Bob

On Feb 18, 2013, at 1:52 AM, Magnus Danielson <magnus at rubidium.dyndns.org> wrote:

> On 02/18/2013 04:34 AM, Bob Camp wrote:
>> Hi
>> 
>> There *must* be an alignment procedure that sets these things up. They didn't put all those test points in there just for the fun of it. I'm sure that these units would work a bit better if we knew how to tweak them back to the original alignment specs.
> 
> There is a document which gives some of it, but doing a reverse-engineering project is primarily so it can be properly understood for trimming and repair purposes in my mind.
> 
> There is a 2x4 connectors which can connect in a test-rig while the 2x5 connector is hooked up. There is two different connectors inside that also should be relevant, and then is at least one jumper field which would be good to know how it "works".
> 
> Considering how common these are, I was surprised that more effort had not gone into them, compared to how the group (and hams) tend to deal with all this.
> 
> Cheers,
> Magnus
> 
>> Bob
>> 
>> On Feb 16, 2013, at 6:10 PM, Magnus Danielson<magnus at rubidium.dyndns.org>  wrote:
>> 
>>> Fellow time-nuts,
>>> 
>>> Considering that LPROs is pretty popular, I am a bit surprised that I have not seen any major reverse-engineering effort on the LPROs. I have the self-compiled LPRO service document, which collects parts of schematics from patents, but still.
>>> 
>>> My main reasons for asking is that I want to get a little better overview of how they work, how I can tune them up and what signals is available where. Naturally, always figuring if there is some interesting tweaks to be done.
>>> 
>>> LRPO is just a traditional analogue rubidium, in compact format, sure, but never the less.
>>> 
>>> I have noticed that different FPGAs have been used over time. Curious about the various jumpers and connectors in it.
>>> 
>>> Cheers,
>>> Magnus
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