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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Sun 24, 2017 3:20 pm 
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spsquires wrote:
Thanks for all the help guys but one question , is it possible for those cap blocks to have a point of connection just for a node and not a capacitor.

I think you are referring to what is commonly called a "tie point". Terminals going to unused tube pins are often used for this purpose, as are terminals on Philco "Bakelite blocks"
On the early--30s capacitor modules, I have never seen this.

BUT-- you have the evidence right in front of you. As you trace everything out, and compare to the schematic, you will know what's what.

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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Sun 24, 2017 4:45 pm 
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So if I take a can apart and it has four components then it means it has four caps.


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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Sun 24, 2017 4:45 pm 
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So if I take a can apart and it has four components then it means it has four caps.


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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Sun 24, 2017 6:07 pm 
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sometimes those modules also have small chokes, but---based on various things posted here--I think not yours.
Once you identify all the parts on the schematic, you'll know for sure

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-Mark http://pixellany.com

"It's always something". --Gilda Radner (1946 - 1989)


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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Mon 25, 2017 12:25 am 
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What may help here is to step by step expand on your layout diagram before you dare to dismantle anything. As I have said before, paint markers can be your friend, take that on board.

Where there are cans with IF transformers, they may have four terminals (a pair for each coil) so you put a colour in a place where it cannot be wiped; Then mark the drawing the same way.

I normally, in a situation like this ( which is ususally a reverse engineering job: No data) Draw the layout of the tubes cans tubes etc. With an AutoCad and number the pin outs of the tubes. You can even go so far as drawing in the plate screen etc. or just use the normal A, G1, G2, K, etc next to the number, and the coils and their resistance.

You can print that: A3 is good. And following some sort of colour code, say green for heater wires, purple for filament wires like #80: Draw a layout diagram, labeling the components as you go. If it is in a can draw dotted lines around it.

This may seem tedious and may require several passes, but will invariably present a learning path & help to identify wrong parts & placements and some times parts missing (seen it) or too many parts (Lyric 70). Once you have that layout diagram you refurbish the set in accordance to it. It also presents the opportunity, to have that layout independently checked to see if it is wrong: I have done that.

Whoever did that to the Lyric 70 (suspect Navy), was not an idiot. It has resonant filters & he re-resonated it for 50Hz.

This is a link to a schematic that was derived this way & it was wired wrongly http://www.kevinchant.com/uploads/7/1/0 ... co_ac5.pdf

Marc


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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Mon 25, 2017 1:46 am 
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Thanks for the advice and information.


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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Mon 25, 2017 2:30 pm 
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Not a really good image, and not complete as I cannot see where some things are, but this to give you an idea of how you can go about reverse engineering the set.

Marc


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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Mon 25, 2017 9:15 pm 
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Thanks Marc I will put that to use and work on this with what time my patience will allow.


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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Tue 26, 2017 12:51 am 
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If you print it A4 then you can add the rest of the coil cans the block caps (cans) & correct & label the 5 pin sockets, they can be redrawn. If you draw resistors & caps as rectangles you can write p/n & value in the rectangle. I suspect the true 5 pin in that may be 5 pin small shell & Pin 3 is away from the other 4? Per Photo

Often doing things the hard way, is the most effective way. You are going to have to replace a lot of wire, most of that rubber coated stuff is finished. Make doubly sure that you have good photos preferably before dismantling. Even if things are wrong, it tells you where they were, before the senior moment. I will often put a dob of paint (marker pen) on the node / terminal that I removed something from, bearing in mind that circuit board cleaner will remove it (& what paint marker you don't want it to remove).

Marc


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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Tue 26, 2017 1:58 am 
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I have photos taken and some wire replaced and one cap block done also.


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 Post subject: Re: rogers majestic r-841
PostPosted: Dec Tue 26, 2017 4:18 am 
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All of us have different ways of doing things. With a set especially where it has proven impossible to find a circuit and there is the highest probability one never will. Nothing is dismantled until such time as it is identified and recorded. Recording includes taking photos of such quality as you can identify, what is going where. As said I do not care at this point, if it is wired wrongly, many are. No damage will be done by me in such circumstances, as it will never have been powered by me at this point.E
It will only be powered (as written several times) when I consider that it is safe to power, or have undertaken remedial works, where I have considered the thing repairable. Many decades experience fixing, notes that powering an unknown set with exuberance and without checking, can render it irreparable, or a very expensive repair.

I have had two sets this year alone, where the only schematic is the one I made by reverse engineering what I had. That always costs a lot of time: But what price success.

Personally I would desist from dismantling anything else until you have an accurate layout diagram. Note that I do have issues with modern "Non outside foil" caps placed in proximity of one another. I normally add grounded shielding if I put them in a can (re-stuff).

At least with this one there is a schematic, so you have a head start in creating a layout diagram.

Marc


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