SOLID-STATE VIBRATOR RETROFIT & ALIGNMENT - 1953 VACUUM TUBE CAR RADIO Pt4 - CHEVY MODEL 986668 [4K]

[@hestheMaster]

Excellent work so far on this fine tube radio. Great signal puller ( DXer) after alignment. There are a lot of weird errors found on schematics over the years. Some are just plain copying errors from hand written notes to a line drawing like the one you found. I have seen plenty where a Selenium rectifier symbol was drawn backwards on the schematic. That is a proofreading error ( maybe they didn't have proofreaders with an electronics background at Howard Sams ) but is easy to spot right away.

[@PracticallyFixed]

Thank you! That error was an interesting discovery; all part of the 'fun'. Thanks again for watching and the comment.

[@jimnewman5596]

I think the decimal point was incorrect on the cathode voltage of the RF stage. That was wise to go to the tube data sheet to calculate a typical cathode current draw.

[@PracticallyFixed]

Doug and I have both been having a time with schematics lately. Thanks

[@tateamatertheoriganal8677]

I got a 1955 vacuum car radio that’s buzzing but no sound is there something wrong or am I not picking up a station

[@DERB_Seymour_Indiana]

On your schematics discrepencies, perhaps some were measured with signal? Again, just goes to show the schematic is not always spot on. I found it somewhat comical that you left the old filter cap for looks and yet the solid state vibrator is plainly in view. :) Nice job getting the signal through the radio peaked.

[@PracticallyFixed]

Hi Doug, thanks. Some discrepancies were the resistors that were installed on the AVC line had different values so there were some Run changes. All the schematics noted No Signal, but the values varied. I did also check some things with a VTVM, which were close to the DMM measurements. I did not use an old VOM to see what it would read. It did mention using meter with a 1000 ohm per volt loading. I can what you mean about the SS vibrator, but my thinking was to make changes such as the vibrator retrofit reversible. The vintage vibrator can be put back in and it will buzz happily away and the "looks" will be right - from the tube side: original. Thanks again!

[@DERB_Seymour_Indiana]

@@PracticallyFixed I understand about the vibrator. I've just always found it amusing how far some people go to make 50-80 year old radios look like they've never been touched. LOL

[@PracticallyFixed]

Yes, that is the thing about hobbies, right?

[@DERB_Seymour_Indiana]

@@PracticallyFixed Right indeed. To each his own. :)