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An Introduction and a Philco 90 issue.
#5

Hi Bob...pleasure to speak to you!  Yes, it looks pretty messy.  I'll try to explain what I did and what you're looking at starting from jump.  Yes I did replace some of the wiring.

I replaced the AC line caps by restuffing the box with the safety caps you recommended.  I tied a lead from both to the ground pin and the other lead from each capacitor to the individual remaining tabs and reinstalled the block in the chassis.  I then created a terminal strip to make wiring to the safety cap block a little more accessible for me.  I soldered it to the center tab on the safety cap giving me 3 point access to the center tab.  The AC line coming in was split.  The hot line went to the center tab terminal strip and the neutral line to the remaining, non ground tab on the safety cap block, the tab to the left side of the center tab.  This neutral tab has a line off it that runs up into the transformer.  Now here is where the funky mess I created begins.

I drew a line off the center tab of the safety cap thereby replacing an original wire that ran from the center tab to the on/off switch.  That's the new wire in the picture coming off the safety cap center terminal strip that runs up to the left, out of sight to the switch.  The other side of the switched wire was replaced as well and spliced to the line that goes into the transformer. 

Now, the resistor on the bottom.  Again, I created 3 point access to the tab all the way to the left end of the resistor coil, tab 1 according to the schematic.  There are 2 wires coming from the transformer connected to this tab...what I am assuming according to the schematic are center tap line 12 and the center tap line from the A circuit, line 4.  The negative side of the first electrolytic is tied to this first terminal as well as is the 250K ohm resistor that runs up to the the Bakelite block above.  If I ground one side of my volt meter to the chassis and measure voltage on this first coil resistor tab when I turn the power on, it bounces all over the place, oscillating between 300V AC, 0V AC, 35V AC etc.  After a minute or two...burning smell and smoke.

Thank you Bob for offering you insights into my difficulties.  I can post pictures of any of my dirty work on this radio you need for diagnostics and possible solutions.  I'm probably doing something extraordinary stupid!!!!

Chris


Messages In This Thread
An Introduction and a Philco 90 issue. - by cknob - 11-23-2021, 09:20 PM
RE: An Introduction and a Philco 90 issue. - by cknob - 11-24-2021, 08:55 AM



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