[TechAssist] Re: RCA P60921 PTK195MT No start-up, have secondary supplies
- From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Tue, 11 Nov 2003 15:55:33 -0500
See if any of these help:
Dead set, will not try to turn on. Checking micro, u13101, found it would
read the eeprom at plug in. After that pin 5 would pulse from 2.5 to 5
volts. Pin 19 stays at 0 volts. Found pin 31, filter cpu at .6 volts, should
be 1.7 volts. Ohms check read 2.5k. Lifted c13312 and set came up and ran.
Replace c13312 off pin 31 of u13101.
--------------------------------
Dead. Had only 2.4 volts on pin 36 of u13101.
Removed flux from circuit board and pin 36 came up to 4.7 volts.
--------------------------------
Dead Set U13101 pins 6,7 & 8 at 5 VDC But the voltage at pin 5 was 0 VDC. We
checked all the supplies and they were all right. Q13501-c was 3VDC and
Q13503-B was at .6 VDC. We found C13504 leaky. Replaced c13504 and t he
reset worked. U13101-5 was back to 2VDC.
Replaced c13504.
------------------------------
Dead, No Attempt To Start; VCC at U13101 Normal, But Standby Clock & Data
Pulsating, As Well As 150V(110V-140V) & 16V(12V-16V) Sources. Checking
Around U14101, Pin 6 Was Pulsating From 8-12V And Pin 2 Was At 7V. We Found
That The Run Diode CR14111, Which Is A Surface-Mount Device, Was Missing
From The Chassis. Replaced The Diode & Restored Normal Operation.
Installed missing cr14111.
---------------------------------
Dead set, error code was 3 showing low on 12vdc line. Servicer lifted pins 3
and 5 of U14701 and pin 6 was only 2.1vdc. Pin 7 was normal The servicer
read 25 ohms to ground on pin 6 of U14701. Lifting CR14705 restored 12vdc
line.
Replacement of shorted cr14705 restored operation.
-------------------------------
Dead set, would not pulse at turn on. Found pin 4 of u13101 (run data) low
at turn on. By lifting jumper jc12106 the set would come up in the service
mode. Found the trace from jc12106 ran under jumper jc12114. By lifting this
jumper the set came up and ran. Cleaned glue under this jumper to repair the
set. Jc12114 is in the audio circuit, off pins 2 and 6 of u11401.
Clean glue from jumper jc12114.
----------------------------------
Set dead. No pulsing. No start. Main power supply up and running checking
the dual voltage reg. ic u14701 we had voltage at pins 1 & 2 (b+) but only
half of the voltages needed at the output pins 7 and 6. Also they would not
drop to 0 vdc when the power button was pushed.
Replacing u14701 repaired the set.
---------------------------------
Bob Waterman, CET® #RI-28
Master Technician License #9109
Service Manager / Parts Manager
Gemini Computer, TV, & Security Alarms
(508)695-7302
(508)695-7769 FAX
geminitv@xxxxxxxxxxxxxxxx
geminitv@xxxxxxx
www.geminicomputertvsecurityalarms.com
----- Original Message -----
From: "Larry Eastman" <videotech@xxxxxxxxxxxx>
To: "techassist" <techassist@xxxxxxxxxxxxx>
Sent: Tuesday, November 11, 2003 3:13 PM
Subject: [TechAssist] RCA P60921 PTK195MT No start-up, have secondary
supplies
> Hi Guys, This 195 chassis is dead, replaced fly (with oem), have all
> voltages around U14101, HOT is not
> shorted, have all secondary voltages, 155, 16, 33, -12, pin 19 of
> micro U3101 has 5v only when I press
> power button then it decays immediately, I can`t tell from this print if
> it`s supposed to be a standby voltage or not
> The following have already been checked
> re-soldered driver transformer
> removed L14401 scraped, re-installed
> R12709 is not cracked
> pin 6 of U14401 to ground is infinite
> CR14107 has 16v Any ideas ???? tia, Larry E
>
> Larry Eastman
> American TV & Electronics
> Crystal River, Fl. 34428
>
>
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