Toshiba TV 26AV502U

[tonydix]

The big problem power led flashes but otherwise set is dead.
Smaller problems I cannot open the service manual I downloaded from elektrotanya I also dwonloaded the viewer but I get
this error message.

The ZEUS ENGINE cannot be located.
This Service Manual requires ZEUS ENGINE.



Any help much appreciated. Tony

[R_J]

Re: Toshiba TV 26AV502U

I never liked that Dr. Zeus software, I found a 32av500 manual, not sure how close it is to what you need

[budm]

Re: Toshiba TV 26AV502U

I run XP and I.E.8 to use ZEUS, I download and install:
ZEUS http://elektrotanya.com/toshiba_zeus.../download.html
And then I install AKAMAI NETSESSION INTERFACE DEMONSTARTION 10MB (INSTALLER.EXE):http://client.akamai.com/misc/demos/...cDownload.html due to Visual Studio Error when I was trying to install the AUTODESK DWF VIEWER. Then install AUTODESK 2013 DWF VIEWER.
After that I am able to open the service manual.

https://www.badcaps.net/forum/showth...t=12027&page=6 POST 104

[tonydix]

Re: Toshiba TV 26AV502U

Thanks guys the 32AV500U has a very similar power board to mine.
AND following Budn's advice and 1 day of downloading I can now view the zeus service manual. Many thanks to both of you.

I disconnected the board from the other boards, set up car light bulbs as loads and powered the power on with 5 volts via a 100 ohm resistor. All the voltages from the power board are correct.
When the power board is connected to the main board the 5 volt supply cannot even manage 3.2 volts so i suspect a short ! But where !
Any further ideas about troubleshooting this would be appreciated.
Thank you guys

[tonydix]

Re: Toshiba TV 26AV502U

Somewhere the constant 5 volts must be changed to 3.3 volts to run the control unit but for the life of me I cannot find it ! The pages on the cicuit diagrames are named as follows and I dont know what all the abbreviations mean. So where should I be looking ?

Precaution
MAIN [2] DDR II SDRAM I_F
MAIN [3] SIO I_F
MAIN [4] HDMI I_F
MAIN [5] Tuner & Demodulator
MAIN [6] Audio In
MAIN [7] SD Video Input
MAIN [8] HD Analog Inputs
MAIN [9] LVDS & Video Out
MAIN [10] GPIO & Guest Bus
MAIN [11] Test Block_NC
MAIN [12] MISC & Connectors
MAIN [13] HD770 Power
MAIN [14] HD770 Ground
MAIN [15] Class-D AMP
MAIN [16] Power & Ground 1
MAIN [17] Power & Ground 2
MAIN [18] DDR II Power & GND
MAIN [19] Reserved
MAIN [20] MCU
POWER [1] POWER
KEY [2] KEY&IO
IR [2] IR

Many thanks

Tony

[budm]

Re: Toshiba TV 26AV502U

100 Ohms load on 5V only draws about 50mA, you need to use 10 oHms 5W to simulate 500mA current draw.

[tonydix]

Re: Toshiba TV 26AV502U

OK so here is the latest. Power board supplies all correct voltages when it is powered up with a resistor between 5 volt standby and pson and when no other boards are connected.
Connect up the main board ( and nothing else) and 5 volt standby drops to 3.3 volts.
All the caps on the mainboard test ok with esr meter.
So is the problem with the mainboard or the power board not being capable of supplying the mainboard needs ?

I need to put on some dummy loads on the power supply, particularly the 5 volt supply. Any idea what sort of load i should apply ?

Thanks

Tony

[budm]

Re: Toshiba TV 26AV502U

Start with 10 Ohms 5W to simulate 0.50A current draw first, the power supply should be able to do 1A.

[tonydix]

Re: Toshiba TV 26AV502U

You are correct. The power supply copes with 1 amp fine and remains steady at 5.09 volts. So now I rig up a voltmeter across the 5 volt supply and an ammeter in the 5 volt supply to the main board .
The meters then go through a cycle every 10 secs or so volts go down from 5.09 to about 3.1 at the same time amps jump from 3 milliamps to well over 1 amp, then a second or two later amps back down to 3 milliamps and volts backup to 5.09. This cycle repeats continuously.
So I presume something on the main board is starting up leading to big current requirements and then safety in the power supply is shutting the supply down.
I am unsure about how to further progress this issue.
Many thanks for all the help
Tony