[TechAssist] Re: RCA PTK195B, mostly dead.

I already unplugged the keyboard and it is still dead most of the time.
I did some more testing this morning and found that the eeprom (U13102)
has only 3 volts on pins 8 (Vcc) and 5 (clock).  Pin 6 (data) has 0
volts on it, instead of the normal 5 volts.  That certainly is not
normal.  

Kevin Wilks
Kevin's TV & Video Repair
Penticton BC Canada
kevintv@xxxxxxx 
 

-----Original Message-----
From: techassist-bounce@xxxxxxxxxxxxx
[mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of tvservice
Sent: Friday, July 30, 2004 6:34 AM
To: techassist@xxxxxxxxxxxxx
Subject: [TechAssist] Re: RCA PTK195B, mostly dead.

Unplug the front panel keyboard see if operates OK with remote.
lift the 1K ohm resistor off micro to U14701 then plug in AC power you
should now always have +5 and +12 out of U14701
Set will not be on until press power,
I have seen this IC intermittent
also remove bottom tuner cover and carefully resolder every ground point
and
sm cap at ground points
Remove glue from micro crystal and resolder
If this set has dual tuners unplug cables to second tuner I have seen
problems on the second tuner assembly cause intermittent dead set.
hth
Robert
tvservice@xxxxxxxxxxxxx
H & H Electronics Inc

----- Original Message ----- 
From: "Kevin" <kevintv@xxxxxxx>
To: "TECH-ASSIST" <techassist@xxxxxxxxxxxxx>
Sent: Friday, July 30, 2004 4:08 AM
Subject: [TechAssist] RCA PTK195B, mostly dead.


> This set works sometimes, but most times not.  When the set does work,
> it will work for a minute and then just shuts off by itself and will
not
> come on.  I have the SM on CD rom and I am following the trouble
> shooting procedure.  I found that when I monitor pin 19 of U13101
> (microprocessor) and press the power button, pin 19 does not go high
as
> it is supposed to.  The micro has 5 volts going to pins 16, 29, 32 and
> 51.  Pins 3 and 20 of U16201 are missing the required 7.5 volts.
After
> that the troubleshooting flowchart tells me to repair the defective
P/S
> source.  So I traced the missing voltage back to U14701, a dual
voltage
> regulator.  Pin 6 is missing 12 volts and pin 7 is missing 5 volts.
Pin
> 1 and 2 both have 18-20 volts which is good.  Pins 3 and 5 are
supposed
> to have the 5 volts from pin 19 of the micro when the set is on.  But
of
> course there is no 5 volts coming from the micro.  The set must be
going
> into shutdown.  What can I check next?  Thanks.
>
> Kevin Wilks
> Kevin's TV & Video Repair
> Penticton BC Canada
> kevintv@xxxxxxx
>
>
>
>
>
------------------------------------------------------------------------
--
---
> Lost Password:
> http://www.tech-assist.org  and select "Login Problems?".
> Email Archives:
> http://www.freelists.org/archives/techassist/



------------------------------------------------------------------------
-----
Lost Password:
http://www.tech-assist.org  and select "Login Problems?".
Email Archives:
http://www.freelists.org/archives/techassist/


-----------------------------------------------------------------------------
Lost Password:
http://www.tech-assist.org  and select "Login Problems?".
Email Archives:
http://www.freelists.org/archives/techassist/

Other related posts: