250 watt mod iron

[W4TWA]

I obtained a 250 watt mod transformer mfg by Collins. The part num is 677n104. The data plate says sec 1 turns ratio 1:15871, sec 2  1:6.2471. Primary imp to sec 1 is 12,500/5000. Working voltage 7500v.
I am wondering if anyone knows what equip and what tubes were used for the mod and final?

[w4bfs]

sounds like a good piece ... the application seems to be for plate modulating a tetrode with the tertiary winding to the screen ... first thing coming to mind is similar to a 4-400 in a globe king (1700V @ 330ma)

[W4TWA]

Ok. I figure there are probably multiple combos that could be applied, just curious how it was originally employed.
Lots of nice stuff at the flea market at Orlando ham fest. More so than the last several years.

[W4RFM]

That may be a broadcast tx piece.  Collins used tetrodes a lot. The 300G, 500 and 20V come to mind. Good find. Wish I was there.

[K0ARA]

 

 From the description I might have a similar transformer.
Its from a Collins 16E, single 813 modulated by 805s.
When I can get out to the garage I will compare part numbers. 

[W2PFY]

Looks to be a moderately high impedance primary that would work well with a pair of 100TH tubes or triode connected 4-125A or triode connected 813's. The use of the types suggested may be not exact per the tube specifications but toss that aside and build it up. With the use of a heising reactor and with the right combinations of plates voltages, it could modulate a one KW dc input to the PA  on voice. I would mount the transformer above dc ground so as not to short it out due to insulation breakdown.


Just mt 32 cents worth based on the inflation index, from my 1941 birth year..