[TechAssist] Re: RCA PROJ. Micro or Memory IC???


Larry i doubt think there is any easy way out on this one. It does look 
like you have something pulling down your data line. I'd go straight to 
the tuner and disconnect the data line there first just to see if that's 
it. But if it's not, you'll have to trace it manually until you can 
isolate the area. That is you'll have to disconnect each connection 
going to that pin on the micro until you found one that brings it back 
up. Then you can go into that area and find the problem. Probably a 
leaking disk cap or elecrrlytic.You could unplug the pip modules and any 
extra audio/video processor modules one at a time and see if the voltage 
rises just to eliminate them quickly.  I've only had one bad eprom in 
the hundreds of these, i've repaired and never had a bad Micro yet.  I 
suppose they could be though (one or the other bad that is).

Ralph Dorsey
Atlas TV Inc.
3945 s 76th St.
Milwaukee.Wi 53220
414-545-2303



Larry E. wrote:

>Fellow Techs, RCA P46731AT, chassis PTK169PGA, I can`t figure which IC 
>is giving me this problem, Using
> front control panel, power& vol up/down work, all other buttons don`t 
>work, OSD is good, channel up/down
>momentarily blanks the set but channel does not change, buttons on 
>remote are exactly the same, If I enter the
>channel numbers, ie, 08,09, etc on the remote the tv changes channels, 
>only goes to 13 then snow so obviously it`s
>defaulted to AIR instead of CABLE, but of course I can`t get set-up menu 
>to come up. Have 5volts to  u3200 the memory ic and  5v to Vdd of Micro, 
> scoped pin 6 of micro while pushing menu button and signal is there, 
>data and
>clock are at memory IC, the only voltage I found low/bad was pin 5 on 
>u3200 which is data pin, it reads 3.95 volts,
>appears it should be a volt higher?? I have the service manual but am 
>stumped at the moment, any help would be
>greatly appreciated, Larry E.
>American TV & Electronics
>Sunny FL.
>
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