The PHILCO Phorum

Hello Everyone!

Help is needed.  I am working on a Zenith L403 tabletop.  I have run into the following 10 Meg resistor which is not on the schematic or the parts list. 

[attachment=6771]

I have also included the schematic, showing where it is currently soldered in.

[attachment=6772]

Did I mention that the radio plays okay?  There is a 10 Meg resistor inside U-1, a couplate unit.  I could understand if the 10 meg addition were soldered in at pin 2 of the 1U5 and pin 3 of the 3V4.  It would indicate that a technician had concluded the 10M in the copulate was bad, but that isn't where it's soldered in.  My aunts had this radio for years, used it daily with no complaints. I am less complacent.  Any ideas?  Thanks,  Joe

The way you show it (not obvious) it's lower end goes to the chassis.
Why? Dunno, maybe improves on hum. Or slide switch scratch when it is slid.

Morzh,

You are absotively correct.  I have a head cold the size of Texas and am not thinking straight.   The 10 Meg connection is one line under, between C10 and R11, and pin 5 of the 3V4.  Joe

Finished!
[attachment=6945]
Selenium Power Supply Before

[attachment=6946]
Power Supply After.  I used a 1N5608, 3A 1KV rated diode, and a 200 ohm and an 82 ohm 5W resistor to compensate for the missing resistance of the selenium.  Voltage is about 1 volt higher than normal; no problem.

Cleaned and reassembled:

[attachment=6947]
[attachment=6948]

Nice!

Out of curiosity, what about the 10meg resistor?

(04-16-2015, 08:14 PM)ecstunter Wrote: [ -> ]Nice!  

Out of curiosity, what about the 10meg resistor?

Thanks!  The 10 meg resistor belonged there.  Without it it was dead.  Apparently they left it out when drawing up the schematic.