Basic transistor question from a newb

[jehuie]

Hi all, I hope I'm posting this in an ok place. I'm repairing a monitor and have located a bad transistor which cross references to part# NTE290A. Our local Fry's Electronics tells me this is no longer available. I have found it online but was hoping to get it working tomorrow and have exhausted my options of local places to find this. So my question is....is there a way to easily determine if there is another compatible transistor that would slide into that spot? Or is it likely that I must find this EXACT replacement? If so I can order one....just was reeeeally hoping to get the project moving!

Thanks for your help!

Actually the original part# listed in the schematics is 2SA673(C).

 

[33by47]

Radio shacks

PNP Bipolar Silcon Transistor
Model: MPS2907 | Catalog #: 276-2023
Should work for $0.99.
These small signal transistors don't uually go bad.
Can you say what your symptons are?
Make are model too?

 

[KeepItSimpleStupid]

These look close. http://www.datasheetcatalog.org/datasheet/siemens/Q60702-S111.pdf This is the PNP version of the NPN 2n2222 or a nice GP transistor.

The problem is there is an A suffix on your part abd there are various Hfe value sortings: http://www.datasheetcatalog.org/datasheet/HitachiSemiconductor/mXwvqrw.pdf The (C) says the Hfe should be between 100 and 200.

Vce also is different.

The 2n2907 seems resonable. Check Vce of the original circuit. Where it's used would also help. Watch lead differences.

The NTE book has pages where they list the basic characteristics and applications of each part.
A Japanease Transistor manual can also be helpful.

I just guessed.

 

[jehuie]

Really? Radio Shack? If that will work that would be awesome. It's actually an old 80's arcade monitor made by Electrohome. Model G07-CB0. I used a troubleshooting guide to trace it down to that transistor. The monitor is basically way too bright and won't dim down with the controls. I pulled the transistor and checked it with the diode reading on my meter and it reads open in both directions from base to emitter so I think it's a goner. Right?

 

[KeepItSimpleStupid]

Measure the voltage between C and E points on the circuit board with the transistor pulled. I don't know where Radio Shack came from? NTE books come from NTE-Electronic Components Supplier-Catalog-Cross Reference-NTE Electronics. I have something like one of these books somewhere: Japanese Semiconductor SPEC MANUALS

I had your symptom once with a CRT terminal and the retrace lines were visible. It had an internal picture tube short.