I recently bougt a HP 4276A LCZ meter for myself and it has the option for Internal DC Bias that isn't fitted to my unit.
The service manual has full schematics, BOM and PCB layout, so recreating the PCB will be trivial, however, sourcing obsolete silicon isn't....
I have found most of the substitutes, but I am having a bit of trouble with a few parts, I'm hoping someone here might be able to give me a nudge in the right direction.
Here's the parts I am looking for:
- HP part number: 1854-0523
Apparently this is a Motorola/Freescale part, with alternative part number SS3091
It's a silicon NPN transistor, 1Watt, 150MHz in a TO-39 case (But case type doesn't matter to me)
It might have a collector to emitter voltage rating of 40V and 500mA source cutoff voltage, but I'm not 100% sure about that.
I can source these from ebay, but I'm looking at over $100 for a pack of 11 delivered.
I need only one...
[EDIT]
I managed to track down some more reliable parameters:
P
d = 1W
F
t = 150MHz
V
ce = 160V
I
c = 0.5A
If I could only get a hfe value, I could work out a substitute....
- AD7530LN
An 0.05% tolerance 10-Bit Multiplying D/A converter by Intersil.
- LF13331N or LF13331D (LF13331N preferred)
A JFET 4pole SPST-NO analogue switch by National Semi.
If anyone can shed some light on sourcing or substituting these, please let me know!