Protecting a horizontal output transistor

[angelos]

Howdy. I get in these CW62C chassis 29 inch LG crt tvs with blown line output transistors and normally all one does to repair them is to replace the 20nf 2kv cap but unfortunately all i can source cheap is fake spares that blow 2 seconds after switch on. The original is a 2SC6090LS but thats become obsolete so now we get supplied with a ST1510FX but these are fake too. I am now being forced to buy the original transistor from the agents at a very high cost. Is there a way i can protect the transistor on switch on? I have my handy 100x probe and would like to view the collector pulse on the transistor.

Your help on this will be greatly appreciated

[budm]

Re: Protecting a horizontal output transistor

The problem is that the fake device may have low breakdown Voltage that is not high enough to be used in the circuit as required. It is like trying to use 100V rating diode in place of the 1000V rating diode, nothing you can do to solve that.

[dick_barton]

Re: Protecting a horizontal output transistor

I don't know if this would help you but it does give details on some high voltage LOP transistor.
https://cdn.badcaps-static.com/pdfs/...68d3c338c3.pdf

[jetadm123]

Re: Protecting a horizontal output transistor

My guess would be the fake devices are using a smaller die than the originals and cannot handle the higher current. Is the genuine transistor slightly heavier than the fake? You could also open them up and compare the two. Regardless, there's nothing you can do if the fake transistors don't measure up electrically to the original. Why don't you contact a reputable parts supplier and find out if they have a genuine in stock substitute for the original?

[petehall347]

Re: Protecting a horizontal output transistor

https://uk.farnell.com/stmicroelectr...ngdom%2Fsearch

[angelos]

Re: Protecting a horizontal output transistor

I send an email to ST Microelectronics asking who is their distributor in south africa but i got no response.

[jetadm123]

Re: Protecting a horizontal output transistor

Maybe: Avnet South Africa. 202 Chelmsford, 2nd Floor, Essex Gardens Nelson Road, Westville Durban, South Africa Phone:+27 (0)31 266 8104.

Also try contacting Fairchild or International Rectifier.