[Test-Equipment] Repair of HP 8640B

[ron wicker]

The NEC part number is 128.  The 2n3053 in the 8640b is larger and not the 
standard tabbed power transistor.  It is just a larger 3 pronged device.  I 
will do some more checking to see what I can find.  I also seem to have a 
board that is not the same as the schematic I downloaded.
Thanks for the comments.
Ron.......

--------------------------------------------------
From: <GandalfG8 at aol.com>
Sent: Thursday, April 15, 2010 5:47 PM
To: <test-equipment at mailman.qth.net>
Subject: Re: [Test-Equipment] Repair of HP 8640B

>
> In a message dated 15/04/2010 23:34:19 GMT Daylight Time,
> rwicker1 at verizon.net writes:
>
> I used a  replacement 723 reg. and an nec sub for the 2n3053.  The sub for
> the 3053  is smaller, telling me that it may overheat.  Ate there sources
> for the  HP parts.
>
>
> --------------------
> The 723 and 2N3053 are standard parts, just for once those aren't HP
> specific part numbers, but all 2N3053s should be the same physical size, 
> ie  in a
> TO39 case.
>
> What was the part number of the NEC replacement?
>
> The 3053 is still available, a quick Ebay search for example showed 
> several
> there, and other similar devices might do, BFY50/51 etc,
>
> I would strongly recommend sourcing the correct part but another option
> would be to use a separate 5 volt supply for now and meter the current. 
> That
> way you could calculate whether your replacement transistor would be fit
> for purpose.
>
> regards
>
> Nigel
> GM8PZR
>
>
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