[TechAssist] Re: Fw: RCA PTK195 lightbox dead at wits end-HELP!!!

Charles sound like a similar problem I had on another chassis. I would start 
to trace the signal with your scope from the button panel as you toggle it. 
In my case a button was defective and could not toggle the start up circuit 
to the micro. I kept going around in circles.
"just an idea".
I might have a trouble shooting guide for the PTK195 if you need it let me 
know will pass it on.
I agree with Gerald might also be a trace of the fluid causing it to loose 
the signal, it is deadly conductive, hard to see..
Bruce.


B&T Electronics
139 Margaret St
Sarnia Ontario
Canada
N7T 2Y3
519 344 1850


----- Original Message ----- 
From: "repair11" <repair11@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, December 08, 2005 4:28 PM
Subject: [TechAssist] Fw: RCA PTK195 lightbox dead at wits end-HELP!!!


>
>
>
>
> RCA PTK 195
>
>
> I have already spent entirely too much time on this, but I am giving it 
> one
> last shot.
>
> I pulled lightbox because of miniscule amount of fluid around micro,dead
> set.  I removed micro, eeprom, and cc connector and cleaned board, there 
> was
> no fluid however ,under any of components. Micro has Vdd and clock, but 
> pin
> 19 will not go high which I discovered is what turns U14701 dual reg on, 
> to
> among other things fire up jungle. Pin 23 and 24 which are supposed to be
> high (5v) are low until you lift micro pins, but can find no short, have
> checked all other scan lines, also KD1 pin of micro is supposed to be
> 2.5v,but is 0 at pin and pad with micro pin lifted or in place. pin4 which
> is I squared C run data line  remained low until I lift R137 which feeds a
> multitude of data lines, after some isolating, I found an outgoing data 
> line
> marked DATAra is lifted 5v comes back, I cannot however find where this
> goes.I have replaced  EEPROM, REG U14701,and MICRO, I have no ideas left,
> any help would be greatly appreciated.
>
>
>
> Charles Betzler
> Best Electronics
> repair11@xxxxxxx
>
>
>
> -----------------------------------------------------------------------------
> This Email List is accessible to the general public through search 
> engines. Remove: http://www.tech-assist.org/remove.htm
> Set Vacation 
> mailto:ecartis@xxxxxxxxxxxxx?subject=set%20techassist%20vacation
> Lost Password: http://www.tech-assist.org  and select "Login Problems?".
> Email Archives: http://www.freelists.org/archives/techassist/
> 


-----------------------------------------------------------------------------
This Email List is accessible to the general public through search engines. 
Remove: http://www.tech-assist.org/remove.htm
Set Vacation mailto:ecartis@xxxxxxxxxxxxx?subject=set%20techassist%20vacation
Lost Password: http://www.tech-assist.org  and select "Login Problems?".
Email Archives: http://www.freelists.org/archives/techassist/

Other related posts: