If I had a 2245 with your problem I'd be looking for... Hmm. Your parts are running naked, right - no heat sink? That's maybe 1W.
An eBay seller has TO-92 VP0116 $15 for 10, glue on a copper fin. But nobody is selling VN1316 AFAICT.
Look at Mouser.com . They don't have any 160V P-channel RF MOSFETs so how about the regular ones? In 150V-300V select the lowest Ciss proxied as gate charge, that's Diodes Inc ZVP2545 in the SOT26-6 package. Put a copper fin on the drain pins and you should be okay.
For N-channel try Vishay SI3440 in TSOP-6. Second lowest gate charge and lowest Ciss.
HTH,
Dave Wise
________________________________
From:
[email protected] <
[email protected]> on behalf of Chris Elmquist via groups.io <chrise@...>
Sent: Wednesday, April 2, 2025 9:28 AM
To:
[email protected] <
[email protected]>
Subject: [TekScopes] horz output FETs in 2245?
I was given a 2245 recently which of course doesn't work too well.
Investigation reveals that Q805 and Q806, in the horizontal right plate
output stage, are cold to the touch.
The service manual, section 6.2 (page 6-19) says,
The MOSFET output transistors (Q801 and Q802 left plate-- Q805 and
Q806 right plate) run hot. If either side is cold, it is defective.
So, that's me and now I need to find a couple of these VDMOS FETs, which
seem to have become quite rare.
They are Tek P/N,
151-1211 VN1316N2 N-Channel VDMOS FET, 160V, 250mA, 40 ohm
151-1212 VP0116N2 P-Channel VDMOS FET, 160V, 250mA, 25 ohm
Has anyone solved this problem with a modern replacement pair? and have
suggested substitutes? These are in TO-39 package which adds additional
challenge but I suppose TO-220 or equiv could be made to fit. Of course,
the real thing would be great too if there is a source.
Thanks for any leads!
Chris
--
Chris Elmquist
