Identifying R-F coil

6/17/2009 1:14:11 AMDave Skidmore

I have a Crosley 556 chasis I am considering rebuilding. On the schematic several major parts have very little said about them, namely the RF coil off the antenna input. It is identified as Item 6,par No, G53 -32001 and described simply as R-F Coil. There is no identifying marks on the can and nothing in any of the diagrams. How can I go about determining what it is so that I might get a replacement or rebuild it?

thanks, Dave

6/17/2009 12:21:27 PMEdd

Sir Dave:

Find the tip of the tail and then follow it to its very end. . . .there you will find the dog.

In your situation find the 34 RF amplifier tube and its top 1st grid cap and its gripping connector plugged in on its top, track that connector's attached wire down and it is wired into the RF assembly which ye seek.

Wouldn't expect any problem from the unit, use an ohmmeter to confirm continuity of its two windings.

73's de Edd

6/17/2009 7:29:08 PMDave Skidmore

I guess I didnt make myself clear. I can look on the schematic and point to the RF coil, or oscillator coil, that's no problem. But if I want to yank out the unit and replace it I need to know what to order, the specifications, tolerances, etc.

The problem is that info is not on the parts list or specified on the schematic. The parts list only carries it as and RR coil, no brand, type, size or anything. I cant replace something if I cant tell what it is.

In situations like this how does one go about the detective work to find the secret?

Dave

6/17/2009 7:30:07 PMDave Skidmore

:I guess I didnt make myself clear. I can look on the schematic and point to the RF coil, or oscillator coil, that's no problem. But if I want to yank out the unit and replace it I need to know what to order, the specifications, tolerances, etc.
:
:The problem is that info is not on the parts list or specified on the schematic. The parts list only carries it as and RF coil, no brand, type, size or anything. I cant replace something if I cant tell what it is.
:
:In situations like this how does one go about the detective work to find the secret?
:
:Dave

6/19/2009 10:12:47 PMRadiodoc

Dave,

If the coil can't be repaired, then your best bet probably would be to try to find a junker that has a good coil.

Radiodoc
***************

::I guess I didnt make myself clear. I can look on the schematic and point to the RF coil, or oscillator coil, that's no problem. But if I want to yank out the unit and replace it I need to know what to order, the specifications, tolerances, etc.
::
::The problem is that info is not on the parts list or specified on the schematic. The parts list only carries it as and RF coil, no brand, type, size or anything. I cant replace something if I cant tell what it is.
::
::In situations like this how does one go about the detective work to find the secret?
::
::Dave

6/20/2009 7:15:15 AMEdd

Sir Dave:

I guess I didnt make myself clear. I can look on the schematic and point to the RF coil, or oscillator coil, that's no problem. But if I want to yank out the unit and replace it I need to know what to order, the specifications, tolerances, etc.

You have probably ALREADY found more info in that part number, than one would ordinarily expect to find , but it certainly doesn't fill you in on the fact as to whether that is an in house part that Crosley made or if acquired by them from some inductor manufacturer.

As far as part acquisition, that would assuredly depend upon obtaining it from a Crosley donor parts set that one might. . . and heavy on that MIGHT. . . happen to be able to locate.

Checking chasis numbers designs before and after that 556 series possibly might find other CROSLEY chassis' to be using that same identical part in them also. and then you would at least be increasing the possible number of donor chassis candidates.

Also, as far as identificatoin, I would expect the norm in identification to be a generic request in the order of:

"I need the RF transformer / coil that is used on the first grid circitry of the Model(s)XXX sets RF amplifier stage."

Versus, I need the RF amp plate coil/transformer to mixer grid coil/transformer of a xxx set.
Those of which, would be the only two RF coils/transformers that are used in the set, the others being the osc coil and the two IF transformers.

Adjunct thoughts:

It looks like the making operational of this set will reqire your acquiring or custom building up a power pack for it, with its
original need of the set initially needing three 45 "B" batteries in series to give 135 VDC for the Main B+ supply and an adjunct
-22 1/2 bias battery with its micro-miniscule power demands. AND THEN, there is the real current hog of the set, in the form of its "A" supply battery, it performing the supplying the filaments power for the set.

If someone else reads this, possibly they can chip in on the aspect of the "air" battery option denoted on the schematic.
One would expect the individual cells being incorporated in forming up the required battery voltage for the "A" battery to be in multiples of 1.5 V if using zinc carbon cells, or multiples of 2V if using lead acid storage cells. This "air" cell which is referrred to, must be putting out a bit in excess of that figure, in the respect of its needing that dropper resistor which is shown in series with the "A" supply line.

The onlytwo "air" cell categories I know of now-a-days, are the small ones used in hearing aids, with their storage life by the advantage of the pull off of the sealing tab to initiate their FULL cell action. BUT, those units only have about the POWER capacity, of powering a gnats golf cart.

The other "air" cells are industrial behemoths that remain inert until the adding of their electrolyte to activate action. They then having limited operational time, until their service cessation and their being taken out of service, with the then draining of the electrolyte and replacemnt of the active electrode elements that were depleted, in order to be ready for the next uses demands.

Lastly , was your selection of the RF Transformer just merely a random selection of a part for an example ?
Now, unless you have some physical evidence of damage or electrically detecting an open winding, THAT part is among the very last items that I would expect to find fault with on a/ that set ?

Once the set is working enough where you might want to confirm its even being at fault, a testing manner would be to use an ~ 15 ft loose wire antenna and clip it onto the 1st grid of the MIXER and see if stations can be picked up, then, if the connection is then moved to the 1st grid of the RF amplifier and if the reception is not better, or at least the same, then one would question the RF stage , but not even then, the sole exclusivity of that RF input transformer.

My suspicions instead, on questionable / deteriorated parts more directed towards a worn volume controls wiper and its companion resistive element by past owners repetetive up and down adjustments or power switch cyclings on and off with time. Or the speaker cone fraying and rotting. Or internal damage from old batteries left in the set and decomposing.

73's de Edd