[Ron Ramirez]

Not so easy, as it turns out...

I hooked it up to a pair of speakers last night and had my signal tracer ready.

This morning, I turned it on and let it play.

After an hour or so, the static began, so I started the signal tracing process.

Unfortunately, I could not find the source of the static. It goes back before the volume control...all the way back to the function switch. I traced as far back as the W15-081 push switch board which is located in between the function switch and the volume control. Static all the way.

I am now wondering if the problem could be in the power supply...something which is in common with all functions (AM, FM, phono, tape, aux). I replaced the electrolytics and the semiconductors on the power supply board...but I didn't touch any of the resistors. Maybe I should have?

This is obviously a thermal problem in that it does not manifest itself until the unit has thoroughly warmed up.

?????

If any of you want to follow along, you can find road maps here:

http://www.philcoradio.com/images/SX1500TD_manual.pdf (WARNING - LARGE FILE - 3.6 MB)
http://www.philcoradio.com/images/SX1500TD_schem.pdf (WARNING - LARGE FILE - 4.7 MB)

Looking at the three B+ outputs from the power supply...

B1 - 65V - measures 78V
B2 - 40V - measures 38V
B3 - 25V - measures 22.5V

Odd that B2 and B3 are a bit low, while B1 is high.