[TechAssist] Re: JVC-AV36950-dead-relay clicks at plug in &red light flashes onceFIX!

Maby this will help somebody else
 
 
 
Q912 was leaky--pc901 opto was open--q942 and q944 were shorted--q943 was 
leaky--ic101(9 volt reg) was putting out 14 volts and that was shutting down 
sweep---ic781 (5.5 volt reg) was putting out 7.5 volts and that was shutting 
down micro.---The only way I could get the smps to work is by putting a 100 
watt light bulb on the 134 volt line as a dummy load, otherwise it shuts right 
down. Then I could run through the rest of the set and check the other 
voltages-----AAGH!!!!!!!!!!!!!!!!!!!!!!!!!!
Shoreline Electronics <jstielau@xxxxxxxx> wrote:Only info we have :

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Text pasted from WinSTIPS 2.0
http://www.ServiceSoftware.com
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JVC AV36950

Dead Smps

Paul Deese CET

Nothing Was Happening In The Smps And Replaced The Str-F6626 Ic And Had A
One-Time Pulsing And Then Had To Unplug Set To Get Another Shot . Careful,
The Main Filter ( C911 ) May/Will Be Charged Very Hot Even After Unplugged
For Two Days And It Blew The Fuse On My Ohmmeter ! To Speed Up Tries, Added
A 27k Ohm 3 Watt Across The Main Filter . Thought I Had An Overload On The
13 Volt Supply Generated By D922 Off Pin 12 Of Smps Transformer ( Marked On
Board ) As I Could Not Get Any B+ Readings . After Chasing Tail For Awhile,
Disconnected The Loads After The Coil L922 And Fired It Again . Waveform On
The C926 Attached To Diode D922 By Way Of Cp901 Told Me That I Had A Bad
Filter 1,000uf At 35 Vdc . Replacing Filter Got Me The "13 Volt" And Still
Shutdown . Figured It May Be Load Sensitive And Reconnected L922 And All Was
Well Afterwards ! Removed My Temporary 27 K Ohm

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JVC AV36950

Dead. Relay Clicks Every 2 Or 3 Seconds



Notes: This Is One Of The Chassis That Have A Complicated On/Off/Shutdown
Circuit With A Number Of Smd Transistors That Lightning Takes Out
Frequently.

I Used The Jvc Troubleshooting Chart I Downloaded And It Eliminated The
Switching And Shutdown Circuit But Eventually Took Me In Circles. The
Clicking Relay Is Ry921 Which Switches The 135v B+ Into Circuit.

I Checked The 135v Rectifier D921 In Circuit And It Checked Ok.

Solution: C921, .0015 At 500v, Shunt For D921 Was Leaky.


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=================================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
(860)399-1861
(860)664-3535 FAX
jstielau@xxxxxxxx
=================================
----- Original Message ----- 
From: "Richard La Placa" 
To: 
Sent: Thursday, July 29, 2004 11:25 AM
Subject: [TechAssist] JVC-AV36950-dead-relay clicks at plug in &red light
flashes once


> Help !
>
> Smps not working. No 5 volts to micro. Changed micro(IC701) , ic901(REG
IC) , also IC421(vert ic) just in case it holds down smps due to no sweep. I
tried opening pin 40 on micro (looks like a shut-down circuit) . None of the
parts I changed seem to be shorted. Is there any way I can bypass some kind
of shut down here to get the smps to operate so I can see what this set has
wrong with it?
> TIA-- any help at all here will be greatly appreciated.
>
>
> Richard La Placa
> Continental TV
> 312 a Park Row
> Chestertown, Md, 21620
> http://www.continentaltv.homestead.com
> 410-778-1113 (voice & fax)
>
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Richard La Placa
Continental TV
312 a Park Row
Chestertown, Md, 21620
http://www.continentaltv.homestead.com
410-778-1113 (voice & fax)
                
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