12-21-2018, 11:15 AM
this whole thread bothers me because it happens to me all the time. i go in on a working set and end up with a problem after simply doing some preventative maintenance work. typically in all cases i have ended up dealing with a problem i did not cause, the problem just simply decided to show up!
so.... i want you to pay attention to something that happened to me out of the blue.
go to your middle knob.
observe the conductors that are "passing through that chassis welded / soldered shield.
***there must be no continuity from that shield to the wire inside it.
de-solder the far end "wires" up near the tube socket or at the what appears to be your volume knob.
set your meter to check to see if this wire has any resistance to the outer shield.
~~this happened out of the blue in my minerva tripic master set.
if you have continuity, disconnect the conductor on both ends and add another wire bypassing it un-shielded for the time being.
another thing.. you must try
flip the radio back around with the tubes facing up.
grasp each end of the chassis while playing and twist the chassis itself slightly ,, your checking to see if there is an intermittent cold solder joint somewhere.
you are going to have to get your hands on a schematic that shows the voltages you are to have with the set playing , these voltages would be for each and every pin usually while you are in AM mode.
sams photo fact info can be had for online purchase and downloadable pdf's.
next..
while the set is on... use a plastic tool to wiggle test all your connections while the set is dialed in to a station you would expect reception on. i would focus heavily on that push button section myself, just by it being upside down, gravity might be playing a role in your making good contact ,, wiggle test your push buttons fairly aggressively.
pick up the powered *OFF* radio and shake it to listen to see if you hear things rattling around in one of the IF's.
rig yourself up a dim light bulb tester which is nothing more than a light bulb in series with the radio sets HOT leg of power.
light should be going bright as the set powers up and then goes almost out when the tubes come on line.
if anything other than this happens, report back.
i would imagine you could rig up a dim light bulb tester on the output leg of your onboard transformer as well., this would give you a way to help isolate which circuit is being affected, yet it would be up to you to figure out what size bulb would apply to which lead,, since some of the secondary may be high voltage and others being very low. your secondary high voltage output might have a center tap you can manipulate to utilize only one of the hv legs at a time to find the right bulb.
if ive given bad advice i expect to hear about it,,
so.... i want you to pay attention to something that happened to me out of the blue.
go to your middle knob.
observe the conductors that are "passing through that chassis welded / soldered shield.
***there must be no continuity from that shield to the wire inside it.
de-solder the far end "wires" up near the tube socket or at the what appears to be your volume knob.
set your meter to check to see if this wire has any resistance to the outer shield.
~~this happened out of the blue in my minerva tripic master set.
if you have continuity, disconnect the conductor on both ends and add another wire bypassing it un-shielded for the time being.
another thing.. you must try
flip the radio back around with the tubes facing up.
grasp each end of the chassis while playing and twist the chassis itself slightly ,, your checking to see if there is an intermittent cold solder joint somewhere.
you are going to have to get your hands on a schematic that shows the voltages you are to have with the set playing , these voltages would be for each and every pin usually while you are in AM mode.
sams photo fact info can be had for online purchase and downloadable pdf's.
next..
while the set is on... use a plastic tool to wiggle test all your connections while the set is dialed in to a station you would expect reception on. i would focus heavily on that push button section myself, just by it being upside down, gravity might be playing a role in your making good contact ,, wiggle test your push buttons fairly aggressively.
pick up the powered *OFF* radio and shake it to listen to see if you hear things rattling around in one of the IF's.
rig yourself up a dim light bulb tester which is nothing more than a light bulb in series with the radio sets HOT leg of power.
light should be going bright as the set powers up and then goes almost out when the tubes come on line.
if anything other than this happens, report back.
i would imagine you could rig up a dim light bulb tester on the output leg of your onboard transformer as well., this would give you a way to help isolate which circuit is being affected, yet it would be up to you to figure out what size bulb would apply to which lead,, since some of the secondary may be high voltage and others being very low. your secondary high voltage output might have a center tap you can manipulate to utilize only one of the hv legs at a time to find the right bulb.
if ive given bad advice i expect to hear about it,,
