[Joe Rossi]

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. 

   

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

   

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

[morzh]

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.

[Joe Rossi]

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

[Joe Rossi]

Finished!
   
Selenium Power Supply Before

   
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:

   
   

[Crist Rigotti]

Nice!

Out of curiosity, what about the 10meg resistor?

[Joe Rossi]

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.