Riddled TV Repair Forum

silv · Joined: 07 Jun 2007 Posts: 57

Hi Guys, I Have here a RCA CTC 185A7,19GT240, and everything is good exept no sound at all not even a hum nothing,i tested all voltages at U902, all voltages and components seem to be right also Pin 6 of U001= 3.7v, the speaker is good because i use same chassis exept it's a TOB tuner, the one with no sound is a stand up Tuner,any ideas?Thanks in advance.

Google

kuhurdler · Joined: 28 Dec 2006 Posts: 2571 Location: Overland Park, KS

1. Remove the center leg of Q1903 and see if sound comes back. That's transistor that controls the speaker mute.

2. check your scope out and make sure there is audio out at pins 48 and/or 50 of U1001

silv · Joined: 07 Jun 2007 Posts: 57

I don't have a scope, what are the voltages at those pins?Thanks.

kuhurdler · Joined: 28 Dec 2006 Posts: 2571 Location: Overland Park, KS

It's an audio signal, before amplification.
there is no constant AC or DC signal you can test for, hence the scope.

Did you try lifting the transistor leg already?

silv · Joined: 07 Jun 2007 Posts: 57

Thanks Khurdler, the Q1903 do not exist,i don't have this chassis service manual.there is a place for a Q902 but is not there, i think the mute Transistor is inside U1001,can someone that has this manual confirm this;I have U902 sound amp pin #1 23v, pi#2 10.50v,pin #3.45v.also i suspect that also might me in the IF stage in the stand up tuner,or the T-4 chip itself, any other suggestions Thanks in advance?

Google

kuhurdler · Joined: 28 Dec 2006 Posts: 2571 Location: Overland Park, KS

alright, I'm with you now. This must be a mono sound.
I'm sending you the manual I have.