2n5818 transistor replacement

[cowboy303]

OK I have a BK Precision 1730 that has a little 2n5818 transistor that is bad.  And I need a replacement for it but the cheepest I can find it is $1 each and that's on eBay which I don't want to do.  So I was wondering if there is a replacement for it that's a bit cheaper.
 

[rsjsouza]

Hi,

When searching at Jameco, the result is a very common BC337 (its characteristics seem very similar)

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_254810_-1

Some repair sites also list this (and others) as equivalents:

http://www.lcdtvrepair.us/transistor/2N5818_Driver_de_audio_--13440

However, always keep in mind that, if the equipment requires precision or depends on a very specific characteristic of the device, an equivalent is not identical...

[vk6zgo]

One trick if the transistor characteristics are very critical to the circuit,is to examine the schematic to see if they also use the same type in a non-critical application,such as turning on an LED,or whatever.
Very carefully remove that transistor,use it to replace the critical one,& fit a substitute part in the non-critical position.

Manufacturers frequently use one type of transistor both in circuits that need its special characteristics,& in other positions that don't,as a method of reducing inventory.

Of course,If the original transistor is in a non-critical position,just replace it with a substitute.

[Codemonkey]

FWIW, towers international transistor selector book also lists the BC337 as an equivalent.

[cowboy303]

One trick if the transistor characteristics are very critical to the circuit,is to examine the schematic to see if they also use the same type in a non-critical application,such as turning on an LED,or whatever.
Very carefully remove that transistor,use it to replace the critical one,& fit a substitute part in the non-critical position.

Manufacturers frequently use one type of transistor both in circuits that need its special characteristics,& in other positions that don't,as a method of reducing inventory.

Of course,If the original transistor is in a non-critical position,just replace it with a substitute.

Good idea I will switch it out with the transistor that runs the constant current led.