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  #1  
Old 12-06-2013, 09:45 PM
frank55 frank55 is offline
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Default Fusivel Resistor? Sony tv repair help

Hi guys i'm a newbe here want to greet everybody:
i ordered 2 - .1Ohms 1/2 resistors from Mouser and they sent me this,has anybody seen these?see attachement pic ,it's to replace Sony .1ohms 1/2 w resistor fusivels for the H.V. and V.


Also i have repaired my Sony kv36hs500 by replacing the 2 Mcz3001D chips 13 months ago and it's doing the intermittent start up again without the fault in the service menu,but it's not frequently just sometimes,since i have previously installed a 18 pin chip socket, one week ago i removed and refitted IC8002 chip and it's not doing it for now. but already ordered 4 MCZ3001DB chips and 2 caps 1200uf 250v, and 2, .1Ohm fusil resistors these caps and resistors are recommended to be replaced with the chips.


you guys think i should replace those 2 caps they show Normal DCR in the circuit and the 2 fusivel resistor show .3ohms on my 87 fluke.

Also you guys thing that i should remove the 18 pin sockets and soder the MCZ30001DB driver chips to the board, some people suggest that the sockets give more trouble then it's worth it, i apreciate you help and input.
here some pic attachements.
Attached Images
File Type: jpg DSC01891.JPG (157.3 KB, 15 views)
File Type: jpg DSC01884.JPG (163.2 KB, 19 views)
File Type: jpg DSC01885.JPG (165.2 KB, 17 views)
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Old 12-06-2013, 10:59 PM
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What is the main problem that cause the first repair???
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Old 12-06-2013, 11:30 PM
frank55 frank55 is offline
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What is the main problem that cause the first repair???
Thanks Dr.Killjoy: 13 month ago i started having an intermittent start up problem 6-7 blinks and the fault not showing on the self- diagnosis screen, this went on for a few months till it started to get worse and then i pulled up the self-diagnosis screen test and i got H-stop 1 or V-stop 1 don't remember very well,all i know i Changed the 2 Power Drivers ICs MCZ30001D and it has been working ever since, last week it started to have the intermenitent start up,since i had made a hole in the side of the back cover to get access to the chips mcz30001d that i had put in 18 pin sockets,i took one out and refitted it and it has been good for 2 weeks now,

can you please also advise me on those .1 ohm resistors that The supplier
sent me! thanks
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Old 12-07-2013, 02:36 AM
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The fusible resistors are fine, they blow open circuit, so if the 0.1ohm resistors read 0.3ohms on your meter that is perfectly normal (the extra 0.2 ohms comes from the meter leads).

That model has problems with the electro caps being close to heatsinks, I can see in your photos two small electro caps at least that have their outer plastic jacket shrunk, that is a definite sign of high heat in the cap and they should be replaced.

Really to repair that properly you need an in-circuit ESR meter to test all the electros, I bet there are 10 or more electros there that need repacing.

Also check with a strong magnifier and bright light all the solder joints on any power components (anything large or on a heatsink).
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Old 12-07-2013, 04:09 AM
frank55 frank55 is offline
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Originally Posted by THE_RB View Post
The fusible resistors are fine, they blow open circuit, so if the 0.1ohm resistors read 0.3ohms on your meter that is perfectly normal (the extra 0.2 ohms comes from the meter leads).

That model has problems with the electro caps being close to heatsinks, I can see in your photos two small electro caps at least that have their outer plastic jacket shrunk, that is a definite sign of high heat in the cap and they should be replaced.

Really to repair that properly you need an in-circuit ESR meter to test all the electros, I bet there are 10 or more electros there that need repacing.

Also check with a strong magnifier and bright light all the solder joints on any power components (anything large or on a heatsink).
Thank you Sir for your help

i have an In- Circuit DCR ESK Cap/Analyzer884

should i also suspect these caps, Film 39000pf cap,Mylar cap 0.1uf, ceramc chip cap 0.04uf in the power supply or these do not fail that easy? thanks in advance.
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Old 12-07-2013, 11:56 AM
frank55 frank55 is offline
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Thank you Sir for your help

i have an In- Circuit DCR ESK Cap/Analyzer884

should i also suspect these caps, Film 39000pf cap,Mylar cap 0.1uf, ceramc chip cap 0.04uf in the power supply or these do not fail that easy? thanks in advance.
sorry my Cap tester is 88 A not 884 In- Circuit DCR ESK Cap/Analyzer88 A
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Old 12-07-2013, 03:46 PM
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Aluminum electrolytic capacitors have a predictable failure rate because of their internal chemistry. The others don't. Mylar, ceramic, polypropylene...all very reliable. Still, if you can check them, do it. If there is any evidence of overheating, replace them. They are very inexpensive. Just don't put them first on your list of suspects. They don't deserve that kind of suspicion.
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Old 12-07-2013, 03:59 PM
frank55 frank55 is offline
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Quote:
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Aluminum electrolytic capacitors have a predictable failure rate because of their internal chemistry. The others don't. Mylar, ceramic, polypropylene...all very reliable. Still, if you can check them, do it. If there is any evidence of overheating, replace them. They are very inexpensive. Just don't put them first on your list of suspects. They don't deserve that kind of suspicion.
Thank you Bro.
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Old 12-07-2013, 05:41 PM
ian field ian field is offline
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The single most common cause of unreliable start up is; start up resistors going high or even completely open. Generally the PSU circuit is powered by an extra winding on the chopper transformer - but a start up supply is required to get it going in the first place. Start up resistors are invariably high resistance and particularly prone to wandering off - especially with the high voltages involved.

Over the years; Sony have used all sorts of weird and wonderful chopper circuits - including a GTO thyristor design and a virtually unfathomable "flying capacitor" charge switched voltage step down circuit.

Who knows what "bear pits" they leave out for service engineers these days!!!
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Old 12-08-2013, 01:51 AM
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Quote:
Originally Posted by ian field View Post
...
Over the years; Sony have used all sorts of weird and wonderful chopper circuits - including a GTO thyristor design and a virtually unfathomable "flying capacitor" charge switched voltage step down circuit.
...
I've still got stocks of Sony thyristors from those sets.

And I remember fixing some of those resonant cap/inductor SMPS supplies, they sent a packet of energy each tiem they switched, and freq was linearly proportional to the output current (making weird noises as you probably know).
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