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AM not working after recapping power supply

S

sabalennon

New Member
I recapped the power supply of my MCS 3223 and it was somewhat successful, I made the hum go and it's sounding a lot better now. However, I believe that in the process I might've moved or fried something that stopped the AM signal from working. What should I look for and where should I look if I want to approach troubleshooting? I'm not terribly worried about it, I never used it and probably never will even if it was fixed, but I would like to at least know what's wrong with it. Thank you!
 

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Did you remove the power board to recap it ? I would start checking rail voltages first. If ok move on to voltages to A. M. board. Are they present and correct ?
Some times moving these old wires and boards can cause connections to come loose. Been down that rabbit hole.
 
there should be a separate power supply form the rails for the tuner in the 12-15v range (generally). sometimes it is activated by having the selector on am or fm, other times its always hot.

Rick has the SM for about $9 plus shipping - I would go git it. you want to find a section in the PS where there is a to220 creating the needed voltage and holding steady. am and fm dont draw much current. GENERALLY. you could get lucky and spot it...the mcs might use a chip for am decoding...you could always check Vcc on the chip for power....
 
IMG_20201202_173759903.jpg

Is this wire pinched or broken ? Clean off all of the excess solder flux on this board with alcohol or acetone. Closely inspect your solder connections for solder bridging or cold solder connections.;)
 
another 3223 thread just cropped up and a copy of ther scm is in there...you can clearly see the PS that spits out 13v
 
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