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Post by part15engineer on Sept 25, 2019 22:20:43 GMT
Need top and bottom detailing components and traces. I'm trying to restore some rev. D and F rangemasters to stock. the ones i have someone modded the dump out of them and they are throwing harmonics and spurs all over the place.
I need high res pictures of top and bottom of Rev. D & F units, specifically detailing stuff like resister color coding, etc.
Thanks.
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Post by Boomer on Sept 26, 2019 0:12:10 GMT
I had some, I'll have to take a look. The bottom side is really hard to find, but I had a few, though I think those came from you a couple of years ago, if they're the ones with the large cement wirewound resistors soldered to them.
I can see why you've had trouble getting your multiple transmitter system on the air!
Boomer
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Post by part15engineer on Sept 26, 2019 0:42:32 GMT
i need them from stock unmodded transmitters. i'm trying to restore those transmitters to stock. they light up my spec an like a Christmas tree out to 16mhz
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Post by Boomer on Sept 26, 2019 7:34:51 GMT
Clifford, the big red toroid
I'll look, I save everything like that, any low power radio info or pictures. I'll check on the downstairs computer, though I don't have much hope, especially on the board bottom. Maybe you could use a schematic and find parts values from that?
I hear you about putting them back to stock, it's a good idea in any case. Also consider where you're checking with your analyzer's probe. If you're picking up inside of the case or near the board, likely you'll see lots of trash, like harmonics, spurs, grass.
That's because these transmitters use PLLs with divider chains, and logic gates that drive square waves into the final stages, so it's normal for the circuit to be noisy by itself, because it uses a lot of frequencies to do what it does. I'd set a transmitter up in a test setting and tune it up if you can, like going on the air, close the case then read the spectrum from 5 feet away, any preamps off.
The antenna coils in these things are narrow band, tens of kilohertz, and can take the square waves from the output stage and filter it all out to acceptable limits.
From what I remember looking at board photos, there are 3 final transistors in parallel, probably MOSFETs that are driven by a logic gate with square waves for high efficiency. The output feeds a loop with 4-5 turns around the big red toroid. The secondary is a tapped coil with lots of wire, in an L network with the output capacitance split between the antenna's capacitance and a piston variable trimmer cap on the board for tuning. That's the high-Q part that does all of the filtering.
That's my understanding of what's going on in the circuit.. I was thinking, maybe you could get some photos from the designers or the company that produces it.
Boomer
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Post by part15engineer on Sept 26, 2019 11:04:55 GMT
well Keith released schematics to me, had to sign an NDA so no i won't give them out to anyone (so don't ask) and i have an email into him about high res pics of boards but yet to hear back from him on that.
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Post by part15engineer on Sept 26, 2019 11:23:34 GMT
there is still something wrong with my unit though. i have 5v on one TP and 1.xx on another and this is at the lowest setting so those mosfets are still being saturated by excessive input energy.
hi res pics of the board would help me figure this out really quickly. especially if they are of the Same vintage as the units i have Rev. F and D.
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Post by Boomer on Sept 26, 2019 18:27:54 GMT
NDAstardlyI can see the company holding you at NDApoint, can't let the plans get out to schematic reseller sites. Maybe the finals are in oscillation, have you tried to set it up and modulate it? You could get clues from that, on the scope or even just listening and tuning around the carrier. Looking at your modded board pictures from April 2018, I see an added 5 watt wirewound resistor, and where the final's B+ comes in, that area, some traces were cut and jumpered. I put a Rangemaster Rev. F topside picture on this post that I saved in 2015, I believe it's was from Ebay. Not really hi-res, but I can see the bands on the resistors well. Boomer
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Post by part15engineer on Sept 27, 2019 2:57:06 GMT
thanks that is a good one and a big help.any chance you can pop it out of there and take one of the bottom as well?
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Post by Boomer on Sept 27, 2019 5:40:08 GMT
Oh, if that Rangemaster were mine, I'd already have photos of both sides and diagrams done of it, and it would be my pleasure to send them. I just saved the picture from the auction, it was probably one I was watching, but I never got a Rangemaster, no. Later I got a Procaster there. The way it's going, you might have to buy a Rangemaster just to have a reference unit.. Can you still find a way to contact the seller at this point to see what they were trying to do? That might give some clues. Worse comes to worst, you could draw a partial schematic of the modifications and where they connect, and compare it with the schematics, to see what needs to be where. Boomer
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Post by station8 on Sept 28, 2019 12:36:01 GMT
Howdy y'all:
Let's talk about getting proper documents!.
First off,working in industrial electronic for 14 years there a procedure!,
1) First contact company for any pictures or schematic or both And any modification changes!. ( NOT YOUR BUDDY'S FIRST!!!! ).
2) Depending If company has or does not have what your looking for then you can ask friends if they can help out what you need.
3) By following this will keep you out of trouble with company Because company can't fill the custom needs unless laws change!.
4) Also keep in mind a customer from our tx company could buy From there competitors and do a reverse engineering drawing of there product and they can't do anything about it I seen this first hand in the company I worked for and they got away with it!.
Now as to rangemaser 1000 company ( Keith Hamilton ).
This is what he should do for his records!.
1) Should make high quality scans of pcb boards only top and bottom Of all rev boards he has!.
2) Make high quality pictures of top and bottom boards of complete Rangemaster units!. ( Components on boards,all rev ).
3) Pcb parts layout pictures of top and bottom boards with components Values on all various rev boards!.
4) Complete rev and modification change list on what was done to each transmitter!.
I hope this helps out
Have fun with the hobby
Station 8
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Post by station8 on Oct 1, 2019 3:30:49 GMT
Howdy y'all: I own the rangemaster 1000 Rev F transmitter I have pictures of this transmitter in my records!,
I put and seal up my equipment in case if I have to bug
Out fast do to hurricane seasons.
If you need pictures still you have to give me time.
Have fun with the hobby
Station 8
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Post by part15engineer on Oct 1, 2019 9:25:41 GMT
yes please get me pics when you can Station8. the dotard that had these before me really messed them up with his golden screwdriver.
Thanks.
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Post by Boomer on Oct 2, 2019 6:18:44 GMT
That sounds bad, do you know what they were trying to modify, like to increase power or things people usually tweak.
At the same time, you also had GPS frequency standards, maybe they were trying to connect those to the units?
Looking at your pictures, I don't see an extreme amount of destruction, a few cut traces and the power resistor added, but the top side of yours, compared to my reference picture doesn't look much different. Some part styles are different, like the 10 ohm resistor, but still the same function.
That's just what I can see though, I wish I was there to take a look.
Just trying to get to the bottom of things, I know it can be frustrating.
Boomer
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Post by part15engineer on Oct 2, 2019 12:17:05 GMT
they were attempting multiple things, increased audio frequency response, increased power, and interface a GPS standard.
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Post by Boomer on Nov 30, 2019 2:07:23 GMT
Variety 1560 AM did you ever get this issue resolved? I'd be interested to know how it went.
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