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Palomar 300A refresh. Assume nothing.

Not bad thanks for the info i sent my to a amp builder in the NE he is going to re-do the 40 and 20-meter band with the correct setting and fix the low side input trimmer with a pot in the back of amp so every time the band is switched simple to adjust
 
NOMAD: If you pay any attention to your Ebay Sales dept. you will note and order from me.
Story begins. I took a 300A in trade years ago for ??
Couple years ago decide it was time to move it forward. Tested tubes / cleaned her up / fired up ...Works all bands 40 thru 10...300 to 400 watts carrier on high drive w/(6 watts drive)...Good to go. Took to XENIA, priced her at $275 as a start...by time to leave was asking $225...took it home placed on shelf...Now 2+ years later, time to move...cleaned the dust and realized this thing had antique caps! :cool: OK had some in-house...swap out the 2/450v and 2/25v...caps. Lace up some very ugly wiring.(that old wire is brittle)and closed her up.
Flip the switch...dark...nothing... WTF ...Check fuses ...both blown...OK Dumass!!! :LOL: :LOL: what did you F'up swapping out those few HV parts...Looked things over, even to a point of removing the board to check for a solder bridge or stay splatter...nada...OK Dumass wtf is up!
Pictures and more in Part 2
All the Best
Gary/W9FNB

PS: I have surmised this is a VERY late production 300A/White face/Chrome top...
This has 4/6KD6's finals...2/ 6lf6's drivers
 
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Check fuses ...both blown
Ah, "both"? It came with one fusholder on the rear of the RF deck. We adopted the habit of putting a 15 Amp fuse in a holder on the power transformer to protect the low-voltage winding. Found that a short on the 12 Volts alone might not trip the AC fuse in time to protect the 12-Volt winding, especially if someone had used a 30-Amp fuse.

I would start by pulling the tubes and trace for a short to ground on the 12 Volts AC.

73
 
A Few pics. This is after removing the board and went ahead and replaced the old 5406 Diodes w/5408 Diodes...(600v vs 1000v 3 amps) still need to redo some busted connections...report thr later...Last two pics...might serve as part of blown fuses issues...Orange wire...(cold solder joint) lifted itself from pad an was moving or toughing the green wire...First issue to resolve is this NASTY power plug...More Later
 

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It came with one fuse holder on the rear of the RF deck?
Yes: See pic #I ... Couples to fan motor and power switch. Not sure how many "people" been in this amp...but there is some real "crummy" wiring done. I know that wire is 60 years old, but it was some cheap SH*T back then...now brittle and insulation is thin. Have found B+ wire going to final Plate choke has copper showing through right at the edge of the board...Still finding "stuff"...Beginning to wonder how this worked 2-3 yrs ago :-)
 

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  • @ heartbreaker3473:
    Hello gentlemen and Ladies. I have the dreaded RCI-2990 receive issue where my radio gets distorted when people get close to my location. I found the C90 Capacitor, but I can not for the life of me find the C89 capacitor. Can or does anyone have a picture of the exact location of C89 ? Thank you in advance, Wes
  • @ AudioShockwav:
    Wes, it's better if you start a thread on the main forum, more people are going to see your question.
  • @ heartbreaker3473:
    Okay, sorry, will put in a forum
  • @ heartbreaker3473:
    I put it in the general disscution help area and started a new thread. Thank you for letting me know.