Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x

Thread Closed

HP 400EL ac voltmeter
#1

 I'm trying to troubleshoot this tester due to erratic readings. I found the (Q7) voltage reading not right.
This transistor has a heat sink that pushes down on top of it. So it runs at least fairly warm. It is in a TO-18 package.
  It is staying cold to touch, any how the voltages called for on schematic are on the left. Mine on right.

Emitter   _-6.7v                                      Emitter -6.7v

Base    -7.4v                  My readings are: Base -7.4 v

Collector    -21.5v                                   Collector  -12v

above  readings were taken to ground with fluke DVM

 The collector voltage seems way low.

 The transistor has the # 3-009 on it. I'm trying to figure out what transistor equivalent to purchase.
It shows it being a PNP on the schematic, but the Mouser site has a 2n3009 as NPN.
http://www.mouser.com/ds/2/68/lssgp056-12668.pdf

 I'm confused Icon_crazy  Here is what mouser shows available.

http://www.mouser.com/Semiconductors/Dis...kaZ1z0y4cn

 Can someone advise me on which transistor I could use as a replacement? Thanks
 Here is the manual with schematic on page 45 and voltage chart on page 32.  all transistors on the tested within +/- 5% except the collector of Q7

file:///C:/Users/Mike/Downloads/400e_service%20(2).pdf
Sorry I see the download of schematic did not work will try to get it up


 
 








 
#2

Whooppppssss. Was looking at the wrong diagram! Your xsistor is HP p/n 1853-009. Couldn't find a crossover but are available here:     http://www.sphere.bc.ca/test/hp-parts/hpparts4.html  
For $7.
http://www.gellerlabs.com/HP%20400E%20EL.pdf

GL

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!

Terry
#3

Thanks Terry. I won't be on here for awhile. While looking for a schematic to download I clicked on a download that turned out to be some kind of virus/trojin hourse it took over the computer and know I'm trying to get rid of it.

By the way its called safefinder and I never seen one you could not uninstall till this one.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
HiFi (Chifi) tube amp build - but my own design.
It's the other forum. I'm also in DIY, but mostly read there. Honestly, I kinda jumped into this without much thought to...TV MAN — 10:43 AM
Philco 71 Code 125
Hello,  I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated.dconant — 07:57 AM
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM
54C Complete Teardown/Rebuild
The main problem with adding a Bluetooth input is that this set lacks a traditional power transformer to isolate it from...radiorich — 11:19 PM
54C Cabinet Refinish
I started stripping this cabinet before it got super chilly out because I knew I wasn't going to be able to work on ...glyphmon — 11:18 PM

[-]
Who's Online
There are currently 4475 online users. [Complete List]
» 1 Member(s) | 4474 Guest(s)
Avatar

>