05-21-2024, 08:09 PM
You have a power harness... I cannot be sure it is correct for battery operation. Usually, the harness is backed by a long phenolic strip that holds all the spade lugs in the correct places.
Do not remove the harness, there is information there. Compare the harness with any of the schematics to find out what the terminals are. Look up and under the edge of the cat there should be numbers molded into the composite socket array next to each wire (whisker). There are no markings on the long terminal strip but between the harness, and whiskers it should be possible to find your way around. Refer to the socket numbers and pins.
Then, do the continuity test using a VOM 1000/ohms/volt is best. A DVM will not show correct continuity reads especially when working around the transformers.
No need to record actual reading in ohms, it is irrelevant it either has continuity or not. Record any error to a list. Expect good audio transformer windings to be no more than 10k often lower.
You have the resistor strip. I will have to see if I have plain jumper strip that I can spare.
It may be possible to make one from perf board, wire and terminal pins. Or, with the correct data, strip off the windings and solder jumper wires. Hate to spoil a good resistor strip though.
Look at page 12 of the PDF this is the correct drawing for the DC battery version. Note the darker wires across the center, that is the jumper connections...
As you become familiar do not remove any connections unless they are confirmed with the schematic. It is VERY EASY to get lost in the 28.
Do confirm that the harness can be used. I suspect that there may be different connections for the "A" supply and possibly bias because of the resistor strip series filaments. Some temp relabeling of the wires with masking tape flags may help.
I'll check in a few days.
Remember, motorcycle mechanics fixed these radios 100 years ago, using the data we see now... Electronic Technicians had not been invented yet...
A good thought. The '99 tube as well as the 120, have thoriated filaments. When the emission gets low, they can be rejuvenated. That, makes it possible to get a better price on low emission tubes and chance that they can be restored to work...
Se here for rejuvenation:
http://www.nostalgiaair.org/References/A...lash08.htm
Have you confirmed the loop?
The top of the cat is cadmium plated and often has green cad. oxide. This can be removed chemically with sodium bi-sulfate, pool acid, then lightly buff. Seal with a wash of white shellac and it will retard turning green again. Solution is 2 oz dry measure to 1qt warm water. Acid works when there is no oil or greasy grime so dish wash soap first then acid dip, only 5 minutes, all in plastic tub, use plastic tools. Rinse with water. excess acid can go in pool or down drain... Store any acid solution in a plastic bottle...
If the acid is used to clean other parts, do not place parts made with mixed metals, the acid will electroplate metals but poorly and blacken them.
The large round RCA 100 cone will sound good, but this radio often had the UZ-1325 hard rubber horn.
Chas
Do not remove the harness, there is information there. Compare the harness with any of the schematics to find out what the terminals are. Look up and under the edge of the cat there should be numbers molded into the composite socket array next to each wire (whisker). There are no markings on the long terminal strip but between the harness, and whiskers it should be possible to find your way around. Refer to the socket numbers and pins.
Then, do the continuity test using a VOM 1000/ohms/volt is best. A DVM will not show correct continuity reads especially when working around the transformers.
No need to record actual reading in ohms, it is irrelevant it either has continuity or not. Record any error to a list. Expect good audio transformer windings to be no more than 10k often lower.
You have the resistor strip. I will have to see if I have plain jumper strip that I can spare.
It may be possible to make one from perf board, wire and terminal pins. Or, with the correct data, strip off the windings and solder jumper wires. Hate to spoil a good resistor strip though.
Look at page 12 of the PDF this is the correct drawing for the DC battery version. Note the darker wires across the center, that is the jumper connections...
As you become familiar do not remove any connections unless they are confirmed with the schematic. It is VERY EASY to get lost in the 28.
Do confirm that the harness can be used. I suspect that there may be different connections for the "A" supply and possibly bias because of the resistor strip series filaments. Some temp relabeling of the wires with masking tape flags may help.
I'll check in a few days.
Remember, motorcycle mechanics fixed these radios 100 years ago, using the data we see now... Electronic Technicians had not been invented yet...
A good thought. The '99 tube as well as the 120, have thoriated filaments. When the emission gets low, they can be rejuvenated. That, makes it possible to get a better price on low emission tubes and chance that they can be restored to work...
Se here for rejuvenation:
http://www.nostalgiaair.org/References/A...lash08.htm
Have you confirmed the loop?
The top of the cat is cadmium plated and often has green cad. oxide. This can be removed chemically with sodium bi-sulfate, pool acid, then lightly buff. Seal with a wash of white shellac and it will retard turning green again. Solution is 2 oz dry measure to 1qt warm water. Acid works when there is no oil or greasy grime so dish wash soap first then acid dip, only 5 minutes, all in plastic tub, use plastic tools. Rinse with water. excess acid can go in pool or down drain... Store any acid solution in a plastic bottle...
If the acid is used to clean other parts, do not place parts made with mixed metals, the acid will electroplate metals but poorly and blacken them.
The large round RCA 100 cone will sound good, but this radio often had the UZ-1325 hard rubber horn.
Chas
Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”
