It is possible that the radio in the past has been repaired. Possibly the speaker became bad and the radio man used what he had, a PM speaker. Is there a resistor where the field coil of the electrodynamic speaker would connect. Perhaps anywhere between 450 to 1200 Ohms.
Radiodoc
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:Hi. I need a diagram for a coronado model 636. I've found one on this group but it is not the same. First, my speaker is a permanent magnet while the diagram show a 450 ohm speaker field coil. Also, some parts are not connected according to the diagram. The electrolytic cap seems original but it has not the same value as indicated on the schematic. Anyone know what happen with this model and where I can find the exact diagram?
:Thanks
:Danny
You may check a few of the Coronado schematics in the resources here and see if you can find something close. Sometimes there is not a certain schematic. There is a Coronado 642 schematic under resources that seems close and uses a PM type speaker. It is a 6-tube set also. You may have to use a schematic that is close and trace out the circuit to find the value of the resistors in question. Someone else on here may be more familiar with your radio and have or know the whereabouts of a schematic for it.
Radiodoc
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::Danny,
::
::It is possible that the radio in the past has been repaired. Possibly the speaker became bad and the radio man used what he had, a PM speaker. Is there a resistor where the field coil of the electrodynamic speaker would connect. Perhaps anywhere between 450 to 1200 Ohms.
::
::Radiodoc
::*****************
::Hi and thanks for the reply. I'm sure that the speaker is original. All the resistor are original too. I've found a resistor of about 1300 ohm 2 watt soldered across two terminals of the three section electrolytic capacitor. Probably the one you mention. I think this radio is a "subject to modification without notice". I could send a photo but I don't want to bother anyone with that. I know that components values tend to change with time. This is why I need the right diagram. The values of capacitor are indicated on themself but resistors are not color coded. How could I know the original value? I hope my english is OK! Thanks
:Danny
:
::
::
:::Hi. I need a diagram for a coronado model 636. I've found one on this group but it is not the same. First, my speaker is a permanent magnet while the diagram show a 450 ohm speaker field coil. Also, some parts are not connected according to the diagram. The electrolytic cap seems original but it has not the same value as indicated on the schematic. Anyone know what happen with this model and where I can find the exact diagram?
:::Thanks
:::Danny
Hey Carl, the diagram you suggested is exactly the one I needed. After a quick look, it seem that all the components on the schematic are the same as what I see in the radio. The coronado 636 is the same as the belmont 636 serie A. My model is a serie B but is not listed on this site. Again, thanks for your help. It's greatly appreciated.
Cheers and 73's
Danny