Zenith L403 Radio - Printable Version
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Zenith L403 Radio - Joe Rossi - 03-29-2015
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
RE: Zenith L403 Radio - morzh - 03-29-2015
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.
RE: Zenith L403 Radio - Joe Rossi - 03-29-2015
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
RE: Zenith L403 Radio - Joe Rossi - 04-16-2015
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:
RE: Zenith L403 Radio - Crist Rigotti - 04-16-2015
Nice!
Out of curiosity, what about the 10meg resistor?
RE: Zenith L403 Radio - Joe Rossi - 04-17-2015
(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.